The calling thread cannot access this object because a different thread owns it

281

My code is as below

public CountryStandards()

{

    InitializeComponent();

    try

    {

        FillPageControls();

    }

    catch (Exception ex)

    {

        MessageBox.Show(ex.Message, "Country Standards", MessageBoxButton.OK, MessageBoxImage.Error);

    }

}



/// <summary>

/// Fills the page controls.

/// </summary>

private void FillPageControls()

{

    popUpProgressBar.IsOpen = true;

    lblProgress.Content = "Loading. Please wait...";

    progress.IsIndeterminate = true;

    worker = new BackgroundWorker();

    worker.DoWork += new System.ComponentModel.DoWorkEventHandler(worker_DoWork);

    worker.ProgressChanged += new System.ComponentModel.ProgressChangedEventHandler(worker_ProgressChanged);

    worker.WorkerReportsProgress = true;

    worker.WorkerSupportsCancellation = true;

    worker.RunWorkerCompleted += new System.ComponentModel.RunWorkerCompletedEventHandler(worker_RunWorkerCompleted);

    worker.RunWorkerAsync();                    

}



private void worker_DoWork(object sender, System.ComponentModel.DoWorkEventArgs e)

{

    GetGridData(null, 0); // filling grid

}



private void worker_ProgressChanged(object sender, System.ComponentModel.ProgressChangedEventArgs e)

{

    progress.Value = e.ProgressPercentage;

}



private void worker_RunWorkerCompleted(object sender, System.ComponentModel.RunWorkerCompletedEventArgs e)

{

    worker = null;

    popUpProgressBar.IsOpen = false;

    //filling Region dropdown

    Standards.UDMCountryStandards objUDMCountryStandards = new Standards.UDMCountryStandards();

    objUDMCountryStandards.Operation = "SELECT_REGION";

    DataSet dsRegionStandards = objStandardsBusinessLayer.GetCountryStandards(objUDMCountryStandards);

    if (!StandardsDefault.IsNullOrEmptyDataTable(dsRegionStandards, 0))

        StandardsDefault.FillComboBox(cmbRegion, dsRegionStandards.Tables[0], "Region", "RegionId");



    //filling Currency dropdown

    objUDMCountryStandards = new Standards.UDMCountryStandards();

    objUDMCountryStandards.Operation = "SELECT_CURRENCY";

    DataSet dsCurrencyStandards = objStandardsBusinessLayer.GetCountryStandards(objUDMCountryStandards);

    if (!StandardsDefault.IsNullOrEmptyDataTable(dsCurrencyStandards, 0))

        StandardsDefault.FillComboBox(cmbCurrency, dsCurrencyStandards.Tables[0], "CurrencyName", "CurrencyId");



    if (Users.UserRole != "Admin")

        btnSave.IsEnabled = false;



}



/// <summary>

/// Gets the grid data.

/// </summary>

/// <param name="sender">The sender.</param>

/// <param name="pageIndex">Index of the page.( used in case of paging)   </pamam>

private void GetGridData(object sender, int pageIndex)

{

    Standards.UDMCountryStandards objUDMCountryStandards = new Standards.UDMCountryStandards();

    objUDMCountryStandards.Operation = "SELECT";

    objUDMCountryStandards.Country = txtSearchCountry.Text.Trim() != string.Empty ? txtSearchCountry.Text : null;

    DataSet dsCountryStandards = objStandardsBusinessLayer.GetCountryStandards(objUDMCountryStandards);

    if (!StandardsDefault.IsNullOrEmptyDataTable(dsCountryStandards, 0) && (chkbxMarketsSearch.IsChecked == true || chkbxBudgetsSearch.IsChecked == true || chkbxProgramsSearch.IsChecked == true))

    {

        DataTable objDataTable = StandardsDefault.FilterDatatableForModules(dsCountryStandards.Tables[0], "Country", chkbxMarketsSearch, chkbxBudgetsSearch, chkbxProgramsSearch);

        dgCountryList.ItemsSource = objDataTable.DefaultView;

    }

    else

    {

        MessageBox.Show("No Records Found", "Country Standards", MessageBoxButton.OK, MessageBoxImage.Information);

        btnClear_Click(null, null);

    }

}

The step objUDMCountryStandards.Country = txtSearchCountry.Text.Trim() != string.Empty ? txtSearchCountry.Text : null; in get grid data throws exception

The calling thread cannot access this object because a different
thread owns it.

What's wrong here?

edited Dec 1 '15 at 21:27

Christos

44.4k84678

asked Mar 16 '12 at 6:07

Kuntady Nithesh

4,403124982

4

possible duplicate of stackoverflow.com/questions/2728896/… , stackoverflow.com/questions/3146942/… , stackoverflow.com/questions/7684206/… , stackoverflow.com/questions/8950347/…

– user166390
Mar 16 '12 at 6:21

add a comment |

281

My code is as below

public CountryStandards()

{

    InitializeComponent();

    try

    {

        FillPageControls();

    }

    catch (Exception ex)

    {

        MessageBox.Show(ex.Message, "Country Standards", MessageBoxButton.OK, MessageBoxImage.Error);

    }

}



/// <summary>

/// Fills the page controls.

/// </summary>

private void FillPageControls()

{

    popUpProgressBar.IsOpen = true;

    lblProgress.Content = "Loading. Please wait...";

    progress.IsIndeterminate = true;

    worker = new BackgroundWorker();

    worker.DoWork += new System.ComponentModel.DoWorkEventHandler(worker_DoWork);

    worker.ProgressChanged += new System.ComponentModel.ProgressChangedEventHandler(worker_ProgressChanged);

    worker.WorkerReportsProgress = true;

    worker.WorkerSupportsCancellation = true;

    worker.RunWorkerCompleted += new System.ComponentModel.RunWorkerCompletedEventHandler(worker_RunWorkerCompleted);

    worker.RunWorkerAsync();                    

}



private void worker_DoWork(object sender, System.ComponentModel.DoWorkEventArgs e)

{

    GetGridData(null, 0); // filling grid

}



private void worker_ProgressChanged(object sender, System.ComponentModel.ProgressChangedEventArgs e)

{

    progress.Value = e.ProgressPercentage;

}



private void worker_RunWorkerCompleted(object sender, System.ComponentModel.RunWorkerCompletedEventArgs e)

{

    worker = null;

    popUpProgressBar.IsOpen = false;

    //filling Region dropdown

    Standards.UDMCountryStandards objUDMCountryStandards = new Standards.UDMCountryStandards();

    objUDMCountryStandards.Operation = "SELECT_REGION";

    DataSet dsRegionStandards = objStandardsBusinessLayer.GetCountryStandards(objUDMCountryStandards);

    if (!StandardsDefault.IsNullOrEmptyDataTable(dsRegionStandards, 0))

        StandardsDefault.FillComboBox(cmbRegion, dsRegionStandards.Tables[0], "Region", "RegionId");



    //filling Currency dropdown

    objUDMCountryStandards = new Standards.UDMCountryStandards();

    objUDMCountryStandards.Operation = "SELECT_CURRENCY";

    DataSet dsCurrencyStandards = objStandardsBusinessLayer.GetCountryStandards(objUDMCountryStandards);

    if (!StandardsDefault.IsNullOrEmptyDataTable(dsCurrencyStandards, 0))

        StandardsDefault.FillComboBox(cmbCurrency, dsCurrencyStandards.Tables[0], "CurrencyName", "CurrencyId");



    if (Users.UserRole != "Admin")

        btnSave.IsEnabled = false;



}



/// <summary>

/// Gets the grid data.

/// </summary>

/// <param name="sender">The sender.</param>

/// <param name="pageIndex">Index of the page.( used in case of paging)   </pamam>

private void GetGridData(object sender, int pageIndex)

{

    Standards.UDMCountryStandards objUDMCountryStandards = new Standards.UDMCountryStandards();

    objUDMCountryStandards.Operation = "SELECT";

    objUDMCountryStandards.Country = txtSearchCountry.Text.Trim() != string.Empty ? txtSearchCountry.Text : null;

    DataSet dsCountryStandards = objStandardsBusinessLayer.GetCountryStandards(objUDMCountryStandards);

    if (!StandardsDefault.IsNullOrEmptyDataTable(dsCountryStandards, 0) && (chkbxMarketsSearch.IsChecked == true || chkbxBudgetsSearch.IsChecked == true || chkbxProgramsSearch.IsChecked == true))

    {

        DataTable objDataTable = StandardsDefault.FilterDatatableForModules(dsCountryStandards.Tables[0], "Country", chkbxMarketsSearch, chkbxBudgetsSearch, chkbxProgramsSearch);

        dgCountryList.ItemsSource = objDataTable.DefaultView;

    }

    else

    {

        MessageBox.Show("No Records Found", "Country Standards", MessageBoxButton.OK, MessageBoxImage.Information);

        btnClear_Click(null, null);

    }

}

The step objUDMCountryStandards.Country = txtSearchCountry.Text.Trim() != string.Empty ? txtSearchCountry.Text : null; in get grid data throws exception

The calling thread cannot access this object because a different
thread owns it.

What's wrong here?

edited Dec 1 '15 at 21:27

Christos

44.4k84678

asked Mar 16 '12 at 6:07

Kuntady Nithesh

4,403124982

4

possible duplicate of stackoverflow.com/questions/2728896/… , stackoverflow.com/questions/3146942/… , stackoverflow.com/questions/7684206/… , stackoverflow.com/questions/8950347/…

– user166390
Mar 16 '12 at 6:21

add a comment |

281

My code is as below

public CountryStandards()

{

    InitializeComponent();

    try

    {

        FillPageControls();

    }

    catch (Exception ex)

    {

        MessageBox.Show(ex.Message, "Country Standards", MessageBoxButton.OK, MessageBoxImage.Error);

    }

}



/// <summary>

/// Fills the page controls.

/// </summary>

private void FillPageControls()

{

    popUpProgressBar.IsOpen = true;

    lblProgress.Content = "Loading. Please wait...";

    progress.IsIndeterminate = true;

    worker = new BackgroundWorker();

    worker.DoWork += new System.ComponentModel.DoWorkEventHandler(worker_DoWork);

    worker.ProgressChanged += new System.ComponentModel.ProgressChangedEventHandler(worker_ProgressChanged);

    worker.WorkerReportsProgress = true;

    worker.WorkerSupportsCancellation = true;

    worker.RunWorkerCompleted += new System.ComponentModel.RunWorkerCompletedEventHandler(worker_RunWorkerCompleted);

    worker.RunWorkerAsync();                    

}



private void worker_DoWork(object sender, System.ComponentModel.DoWorkEventArgs e)

{

    GetGridData(null, 0); // filling grid

}



private void worker_ProgressChanged(object sender, System.ComponentModel.ProgressChangedEventArgs e)

{

    progress.Value = e.ProgressPercentage;

}



private void worker_RunWorkerCompleted(object sender, System.ComponentModel.RunWorkerCompletedEventArgs e)

{

    worker = null;

    popUpProgressBar.IsOpen = false;

    //filling Region dropdown

    Standards.UDMCountryStandards objUDMCountryStandards = new Standards.UDMCountryStandards();

    objUDMCountryStandards.Operation = "SELECT_REGION";

    DataSet dsRegionStandards = objStandardsBusinessLayer.GetCountryStandards(objUDMCountryStandards);

    if (!StandardsDefault.IsNullOrEmptyDataTable(dsRegionStandards, 0))

        StandardsDefault.FillComboBox(cmbRegion, dsRegionStandards.Tables[0], "Region", "RegionId");



    //filling Currency dropdown

    objUDMCountryStandards = new Standards.UDMCountryStandards();

    objUDMCountryStandards.Operation = "SELECT_CURRENCY";

    DataSet dsCurrencyStandards = objStandardsBusinessLayer.GetCountryStandards(objUDMCountryStandards);

    if (!StandardsDefault.IsNullOrEmptyDataTable(dsCurrencyStandards, 0))

        StandardsDefault.FillComboBox(cmbCurrency, dsCurrencyStandards.Tables[0], "CurrencyName", "CurrencyId");



    if (Users.UserRole != "Admin")

        btnSave.IsEnabled = false;



}



/// <summary>

/// Gets the grid data.

/// </summary>

/// <param name="sender">The sender.</param>

/// <param name="pageIndex">Index of the page.( used in case of paging)   </pamam>

private void GetGridData(object sender, int pageIndex)

{

    Standards.UDMCountryStandards objUDMCountryStandards = new Standards.UDMCountryStandards();

    objUDMCountryStandards.Operation = "SELECT";

    objUDMCountryStandards.Country = txtSearchCountry.Text.Trim() != string.Empty ? txtSearchCountry.Text : null;

    DataSet dsCountryStandards = objStandardsBusinessLayer.GetCountryStandards(objUDMCountryStandards);

    if (!StandardsDefault.IsNullOrEmptyDataTable(dsCountryStandards, 0) && (chkbxMarketsSearch.IsChecked == true || chkbxBudgetsSearch.IsChecked == true || chkbxProgramsSearch.IsChecked == true))

    {

        DataTable objDataTable = StandardsDefault.FilterDatatableForModules(dsCountryStandards.Tables[0], "Country", chkbxMarketsSearch, chkbxBudgetsSearch, chkbxProgramsSearch);

        dgCountryList.ItemsSource = objDataTable.DefaultView;

    }

    else

    {

        MessageBox.Show("No Records Found", "Country Standards", MessageBoxButton.OK, MessageBoxImage.Information);

        btnClear_Click(null, null);

    }

}

The step objUDMCountryStandards.Country = txtSearchCountry.Text.Trim() != string.Empty ? txtSearchCountry.Text : null; in get grid data throws exception

The calling thread cannot access this object because a different
thread owns it.

What's wrong here?

edited Dec 1 '15 at 21:27

Christos

44.4k84678

asked Mar 16 '12 at 6:07

Kuntady Nithesh

4,403124982

My code is as below

public CountryStandards()

{

    InitializeComponent();

    try

    {

        FillPageControls();

    }

    catch (Exception ex)

    {

        MessageBox.Show(ex.Message, "Country Standards", MessageBoxButton.OK, MessageBoxImage.Error);

    }

}



/// <summary>

/// Fills the page controls.

/// </summary>

private void FillPageControls()

{

    popUpProgressBar.IsOpen = true;

    lblProgress.Content = "Loading. Please wait...";

    progress.IsIndeterminate = true;

    worker = new BackgroundWorker();

    worker.DoWork += new System.ComponentModel.DoWorkEventHandler(worker_DoWork);

    worker.ProgressChanged += new System.ComponentModel.ProgressChangedEventHandler(worker_ProgressChanged);

    worker.WorkerReportsProgress = true;

    worker.WorkerSupportsCancellation = true;

    worker.RunWorkerCompleted += new System.ComponentModel.RunWorkerCompletedEventHandler(worker_RunWorkerCompleted);

    worker.RunWorkerAsync();                    

}



private void worker_DoWork(object sender, System.ComponentModel.DoWorkEventArgs e)

{

    GetGridData(null, 0); // filling grid

}



private void worker_ProgressChanged(object sender, System.ComponentModel.ProgressChangedEventArgs e)

{

    progress.Value = e.ProgressPercentage;

}



private void worker_RunWorkerCompleted(object sender, System.ComponentModel.RunWorkerCompletedEventArgs e)

{

    worker = null;

    popUpProgressBar.IsOpen = false;

    //filling Region dropdown

    Standards.UDMCountryStandards objUDMCountryStandards = new Standards.UDMCountryStandards();

    objUDMCountryStandards.Operation = "SELECT_REGION";

    DataSet dsRegionStandards = objStandardsBusinessLayer.GetCountryStandards(objUDMCountryStandards);

    if (!StandardsDefault.IsNullOrEmptyDataTable(dsRegionStandards, 0))

        StandardsDefault.FillComboBox(cmbRegion, dsRegionStandards.Tables[0], "Region", "RegionId");



    //filling Currency dropdown

    objUDMCountryStandards = new Standards.UDMCountryStandards();

    objUDMCountryStandards.Operation = "SELECT_CURRENCY";

    DataSet dsCurrencyStandards = objStandardsBusinessLayer.GetCountryStandards(objUDMCountryStandards);

    if (!StandardsDefault.IsNullOrEmptyDataTable(dsCurrencyStandards, 0))

        StandardsDefault.FillComboBox(cmbCurrency, dsCurrencyStandards.Tables[0], "CurrencyName", "CurrencyId");



    if (Users.UserRole != "Admin")

        btnSave.IsEnabled = false;



}



/// <summary>

/// Gets the grid data.

/// </summary>

/// <param name="sender">The sender.</param>

/// <param name="pageIndex">Index of the page.( used in case of paging)   </pamam>

private void GetGridData(object sender, int pageIndex)

{

    Standards.UDMCountryStandards objUDMCountryStandards = new Standards.UDMCountryStandards();

    objUDMCountryStandards.Operation = "SELECT";

    objUDMCountryStandards.Country = txtSearchCountry.Text.Trim() != string.Empty ? txtSearchCountry.Text : null;

    DataSet dsCountryStandards = objStandardsBusinessLayer.GetCountryStandards(objUDMCountryStandards);

    if (!StandardsDefault.IsNullOrEmptyDataTable(dsCountryStandards, 0) && (chkbxMarketsSearch.IsChecked == true || chkbxBudgetsSearch.IsChecked == true || chkbxProgramsSearch.IsChecked == true))

    {

        DataTable objDataTable = StandardsDefault.FilterDatatableForModules(dsCountryStandards.Tables[0], "Country", chkbxMarketsSearch, chkbxBudgetsSearch, chkbxProgramsSearch);

        dgCountryList.ItemsSource = objDataTable.DefaultView;

    }

    else

    {

        MessageBox.Show("No Records Found", "Country Standards", MessageBoxButton.OK, MessageBoxImage.Information);

        btnClear_Click(null, null);

    }

}

The step objUDMCountryStandards.Country = txtSearchCountry.Text.Trim() != string.Empty ? txtSearchCountry.Text : null; in get grid data throws exception

The calling thread cannot access this object because a different
thread owns it.

What's wrong here?

c# wpf multithreading backgroundworker

edited Dec 1 '15 at 21:27

Christos

44.4k84678

asked Mar 16 '12 at 6:07

Kuntady Nithesh

4,403124982

edited Dec 1 '15 at 21:27

Christos

44.4k84678

asked Mar 16 '12 at 6:07

Kuntady Nithesh

4,403124982

edited Dec 1 '15 at 21:27

Christos

44.4k84678

edited Dec 1 '15 at 21:27

Christos

44.4k84678

edited Dec 1 '15 at 21:27

Christos

44.4k84678

asked Mar 16 '12 at 6:07

Kuntady Nithesh

4,403124982

asked Mar 16 '12 at 6:07

Kuntady Nithesh

4,403124982

asked Mar 16 '12 at 6:07

Kuntady Nithesh

4,403124982

4

possible duplicate of stackoverflow.com/questions/2728896/… , stackoverflow.com/questions/3146942/… , stackoverflow.com/questions/7684206/… , stackoverflow.com/questions/8950347/…

– user166390
Mar 16 '12 at 6:21

add a comment |

4

possible duplicate of stackoverflow.com/questions/2728896/… , stackoverflow.com/questions/3146942/… , stackoverflow.com/questions/7684206/… , stackoverflow.com/questions/8950347/…

– user166390
Mar 16 '12 at 6:21

possible duplicate of stackoverflow.com/questions/2728896/… , stackoverflow.com/questions/3146942/… , stackoverflow.com/questions/7684206/… , stackoverflow.com/questions/8950347/…

– user166390
Mar 16 '12 at 6:21

add a comment |

13 Answers
13

active

oldest

votes

569

This is a common problem with people getting started. Whenever you update your UI elements from a thread other than the main thread, you need to use:

this.Dispatcher.Invoke(() =>

{

    ...// your code here.

});

You can also use control.Dispatcher.CheckAccess() to check whether the current thread owns the control. If it does own it, your code looks as normal. Otherwise, use above pattern.

edited Feb 12 '17 at 0:18

oddRaven

345417

answered Mar 16 '12 at 6:22

Candide

24k64651

3

I have the same problem as OP; My problem now is that the event causes now a stack overflow. :

– Malavos
Jan 22 '14 at 12:14

1

Went back to my old project and solved this. Also, I had forgotten to +1 this. This method works quite well! It improve my application loading time on 10seconds or even more, just by using threads to load our localized resources. Cheers!

– Malavos
May 7 '14 at 13:21

3

If I'm not wrong you can't even read a UI object from a non-owner thread; surprised me a bit.

– Elliot
Mar 2 '15 at 9:25

22

Application.Current.Dispatcher.Invoke(MyMethod, DispatcherPriority.ContextIdle); to get the dispatcher if not on the UI thread as per this answer

– JumpingJezza
Aug 21 '15 at 2:59

2

@Candide am still getting this error

– Meer
May 7 '16 at 6:13

|
show 3 more comments

Another good use for Dispatcher.Invoke is for immediately updating the UI in a function that performs other tasks:

// Force WPF to render UI changes immediately with this magic line of code...

Dispatcher.Invoke(new Action(() => { }), DispatcherPriority.ContextIdle);

I use this to update button text to "Processing..." and disable it while making WebClient requests.

edited Jan 12 '18 at 4:37

Lauraducky

539823

answered Jun 17 '14 at 19:03

computerGuyCJ

63058

4

This answer is being discussed on Meta. meta.stackoverflow.com/questions/361844/…

– JDB
Jan 12 '18 at 15:56

This stopped my control from getting data from internet?

– user4350912
Mar 6 '18 at 16:50

add a comment |

To add my 2 cents, the exception can occur even if you call your code through System.Windows.Threading.Dispatcher.CurrentDispatcher.Invoke().
The point is that you have to call Invoke() of the Dispatcher of the control that you're trying to access, which in some cases may not be the same as System.Windows.Threading.Dispatcher.CurrentDispatcher. So instead you should use YourControl.Dispatcher.Invoke() to be safe. I was banging my head for a couple of hours before I realized this.

Update

For future readers, it looks like this has changed in the newer versions of .NET (4.0 and above). Now you no longer have to worry about the correct dispatcher when updating UI-backing properties in your VM. WPF engine will marshal cross-thread calls on the correct UI thread. See more details here. Thanks to @aaronburro for the info and link. You may also want to read our conversation below in comments.

edited Mar 26 at 18:15

answered Oct 21 '15 at 4:31

dotNET

18.3k1387148

4

@l33t: WPF supports multiple UI threads in one application, each of which will have its own Dispatcher. In those cases (which are admittedly rare), calling Control.Dispatcher is the safe approach. For reference you can see this article as well as this SO post (particularly Squidward's answer).

– dotNET
Sep 27 '16 at 10:13

1

Interestingly, I was facing this very exception when I googled and landed on this page and like most of us do, tried the highest voted answer, which didn't solve my issue then. I then found out this reason and posted it here for peer developers.

– dotNET
Sep 27 '16 at 10:15

1

@l33t, if you are using MVVM correctly, then it shouldn't be a problem. The view necessarily know what Dispatcher it is using, whilehe ViewModels and Models know nothing of controls and have no need to know of controls.

– aaronburro
Feb 23 '18 at 14:54

1

@aaronburro: Problem is that VM may want to launch actions on alternate threads (e.g. Tasks, Timer-based actions, Parallel queries), and as the operation progresses, may like to update UI (through RaisePropertyChanged etc), which will in turn try to access a UI control from non-UI thread and thus result in this exception. I don't know of a correct MVVM approach that would solve this problem.

– dotNET
Feb 24 '18 at 8:39

1

The WPF binding engine automatically marshals property change events to the correct Dispatcher. This is why VM has no need to know of the Dispatcher; all it has to do is just raise property changed events. WinForms binding is a different story.

– aaronburro
Aug 17 '18 at 20:31

|
show 15 more comments

If anyone tries to work with BitmapSource in WPF and threads and has this same message: just call Freeze() method first before passing a BitmapSource as a thread parameter.

edited Apr 23 '18 at 8:59

Hakam Fostok

5,72284470

answered Nov 25 '15 at 12:59

juFo

10.9k761110

15

Ah, nothing like a good old vague and mysterious trick to solve something nobody understands.

– Edwin
Mar 4 '17 at 10:43

1

I'd love more information about why this works and how I could have figured it out myself.

– Xavier Shay
Feb 28 '18 at 17:45

@XavierShay docs.microsoft.com/en-us/dotnet/framework/wpf/advanced/…

– juFo
Mar 1 '18 at 10:36

add a comment |

this happened with me because I tried to access UI component in another thread insted of UI thread

like this

private void button_Click(object sender, RoutedEventArgs e)

{

    new Thread(SyncProcces).Start();

}



private void SyncProcces()

{

    string val1 = null, val2 = null;

    //here is the problem 

    val1 = textBox1.Text;//access UI in another thread

    val2 = textBox2.Text;//access UI in another thread

    localStore = new LocalStore(val1);

    remoteStore = new RemoteStore(val2);

}

to solve this problem, wrap any ui call inside what Candide mentioned above in his answer

private void SyncProcces()

{

    string val1 = null, val2 = null;

    this.Dispatcher.Invoke((Action)(() =>

    {//this refer to form in WPF application 

        val1 = textBox.Text;

        val2 = textBox_Copy.Text;

    }));

    localStore = new LocalStore(val1);

    remoteStore = new RemoteStore(val2 );

}

edited May 23 '17 at 12:02

Community♦

answered Jun 27 '16 at 7:59

Basheer AL-MOMANI

6,98814866

1

Upvoted, because this is not a duplicate answer or plagiaristic, but it instead provides a good example that other answers were lacking, while giving credit for what was posted earlier.

– Panzercrisis
Sep 2 '16 at 15:24

Upvote is for a clear answer. Although same was written by others, but this make it clear for anyone who is stuck.

– NishantM
Mar 4 '17 at 7:11

add a comment |

You need to Update in to the UI, So use

Dispatcher.BeginInvoke(new Action(() => {GetGridData(null, 0)}));

edited Mar 5 '13 at 12:02

Taryn♦

193k47295358

answered Mar 5 '13 at 11:27

VikramBose

193110

add a comment |

For some reason Candide's answer didn't build. It was helpful, though, as it led me to find this, which worked perfectly:

System.Windows.Threading.Dispatcher.CurrentDispatcher.Invoke((Action)(() =>

    {

       //your code here...

    }));

answered Jul 12 '15 at 10:44

Sarah

168126

It's possible that you didn't call from the form's class. Either you can grab a reference to the Window, or you can probably use what you suggested.

– Simone
Nov 12 '15 at 11:05

4

If it worked for you, it was unnecessary to use it in the first place. System.Windows.Threading.Dispatcher.CurrentDispatcher is the dispatcher for the current thread. That means if you're on a background thread, it's not going to be the UI thread's dispatcher. To access the UI thread's dispatcher, use System.Windows.Application.Current.Dispatcher.

– Will
Sep 1 '17 at 14:46

add a comment |

I also found that System.Windows.Threading.Dispatcher.CurrentDispatcher.Invoke() is not always dispatcher of target control, just as dotNet wrote in his answer. I didn't had access to control's own dispatcher, so I used Application.Current.Dispatcher and it solved the problem.

answered May 11 '17 at 11:45

Paulus Limma

8516

add a comment |

The problem is that you are calling GetGridData from a background thread. This method accesses several WPF controls which are bound to the main thread. Any attempt to access them from a background thread will lead to this error.

In order to get back to the correct thread you should use SynchronizationContext.Current.Post. However in this particular case it seems like the majority of the work you are doing is UI based. Hence you would be creating a background thread just to go immediately back to the UI thread and do some work. You need to refactor your code a bit so that it can do the expensive work on the background thread and then post the new data to the UI thread afterwards

answered Mar 16 '12 at 6:18

JaredPar

581k12110751354

add a comment |

As mentioned here, Dispatcher.Invoke could freeze the UI. Should use Dispatcher.BeginInvoke instead.

Here is a handy extension class to simplify the checking and calling dispatcher invocation.

Sample usage: (call from WPF window)

this Dispatcher.InvokeIfRequired(new Action(() =>

{

    logTextbox.AppendText(message);

    logTextbox.ScrollToEnd();

}));

Extension class:

using System;

using System.Windows.Threading;



namespace WpfUtility

{

    public static class DispatcherExtension

    {

        public static void InvokeIfRequired(this Dispatcher dispatcher, Action action)

        {

            if (dispatcher == null)

            {

                return;

            }

            if (!dispatcher.CheckAccess())

            {

                dispatcher.BeginInvoke(action, DispatcherPriority.ContextIdle);

                return;

            }

            action();

        }

    }

}

edited Mar 29 '18 at 12:53

answered Mar 28 '18 at 22:23

Jeson Martajaya

4,35563644

add a comment |

This works for me.

new Thread(() =>

        {



        Thread.CurrentThread.IsBackground = false;

        Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Background, (SendOrPostCallback)delegate {



          //Your Code here.



        }, null);

        }).Start();

edited Dec 26 '18 at 3:19

answered Jun 15 '18 at 15:41

nPcomp

3,10211929

add a comment |

Also, another solution is ensuring your controls are created in UI thread, not by a background worker thread for example.

answered Feb 23 '17 at 8:27

FindOutIslamNow

3561417

add a comment |

I kept getting the error when I added cascading comboboxes to my WPF application, and resolved the error by using this API:

    using System.Windows.Data;



    private readonly object _lock = new object();

    private CustomObservableCollection<string> _myUiBoundProperty;

    public CustomObservableCollection<string> MyUiBoundProperty

    {

        get { return _myUiBoundProperty; }

        set

        {

            if (value == _myUiBoundProperty) return;

            _myUiBoundProperty = value;

            NotifyPropertyChanged(nameof(MyUiBoundProperty));

        }

    }



    public MyViewModelCtor(INavigationService navigationService) 

    {

       // Other code...

       BindingOperations.EnableCollectionSynchronization(AvailableDefectSubCategories, _lock );



    }

For details, please see https://msdn.microsoft.com/query/dev14.query?appId=Dev14IDEF1&l=EN-US&k=k(System.Windows.Data.BindingOperations.EnableCollectionSynchronization);k(TargetFrameworkMoniker-.NETFramework,Version%3Dv4.7);k(DevLang-csharp)&rd=true

answered Jun 15 '18 at 19:00

user8128167

2,82053652

add a comment |

protected by Community♦ Apr 17 '17 at 17:18

Thank you for your interest in this question.
Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).

Would you like to answer one of these unanswered questions instead?

13 Answers
13

active

oldest

votes

13 Answers
13

active

oldest

votes

569

This is a common problem with people getting started. Whenever you update your UI elements from a thread other than the main thread, you need to use:

this.Dispatcher.Invoke(() =>

{

    ...// your code here.

});

You can also use control.Dispatcher.CheckAccess() to check whether the current thread owns the control. If it does own it, your code looks as normal. Otherwise, use above pattern.

edited Feb 12 '17 at 0:18

oddRaven

345417

answered Mar 16 '12 at 6:22

Candide

24k64651

3

I have the same problem as OP; My problem now is that the event causes now a stack overflow. :

– Malavos
Jan 22 '14 at 12:14

1

Went back to my old project and solved this. Also, I had forgotten to +1 this. This method works quite well! It improve my application loading time on 10seconds or even more, just by using threads to load our localized resources. Cheers!

– Malavos
May 7 '14 at 13:21

3

If I'm not wrong you can't even read a UI object from a non-owner thread; surprised me a bit.

– Elliot
Mar 2 '15 at 9:25

22

Application.Current.Dispatcher.Invoke(MyMethod, DispatcherPriority.ContextIdle); to get the dispatcher if not on the UI thread as per this answer

– JumpingJezza
Aug 21 '15 at 2:59

2

@Candide am still getting this error

– Meer
May 7 '16 at 6:13

|
show 3 more comments

569

This is a common problem with people getting started. Whenever you update your UI elements from a thread other than the main thread, you need to use:

this.Dispatcher.Invoke(() =>

{

    ...// your code here.

});

You can also use control.Dispatcher.CheckAccess() to check whether the current thread owns the control. If it does own it, your code looks as normal. Otherwise, use above pattern.

edited Feb 12 '17 at 0:18

oddRaven

345417

answered Mar 16 '12 at 6:22

Candide

24k64651

3

I have the same problem as OP; My problem now is that the event causes now a stack overflow. :

– Malavos
Jan 22 '14 at 12:14

1

Went back to my old project and solved this. Also, I had forgotten to +1 this. This method works quite well! It improve my application loading time on 10seconds or even more, just by using threads to load our localized resources. Cheers!

– Malavos
May 7 '14 at 13:21

3

If I'm not wrong you can't even read a UI object from a non-owner thread; surprised me a bit.

– Elliot
Mar 2 '15 at 9:25

22

Application.Current.Dispatcher.Invoke(MyMethod, DispatcherPriority.ContextIdle); to get the dispatcher if not on the UI thread as per this answer

– JumpingJezza
Aug 21 '15 at 2:59

2

@Candide am still getting this error

– Meer
May 7 '16 at 6:13

|
show 3 more comments

569

This is a common problem with people getting started. Whenever you update your UI elements from a thread other than the main thread, you need to use:

this.Dispatcher.Invoke(() =>

{

    ...// your code here.

});

You can also use control.Dispatcher.CheckAccess() to check whether the current thread owns the control. If it does own it, your code looks as normal. Otherwise, use above pattern.

edited Feb 12 '17 at 0:18

oddRaven

345417

answered Mar 16 '12 at 6:22

Candide

24k64651

This is a common problem with people getting started. Whenever you update your UI elements from a thread other than the main thread, you need to use:

this.Dispatcher.Invoke(() =>

{

    ...// your code here.

});

You can also use control.Dispatcher.CheckAccess() to check whether the current thread owns the control. If it does own it, your code looks as normal. Otherwise, use above pattern.

edited Feb 12 '17 at 0:18

oddRaven

345417

answered Mar 16 '12 at 6:22

Candide

24k64651

edited Feb 12 '17 at 0:18

oddRaven

345417

edited Feb 12 '17 at 0:18

oddRaven

345417

edited Feb 12 '17 at 0:18

oddRaven

345417

answered Mar 16 '12 at 6:22

Candide

24k64651

answered Mar 16 '12 at 6:22

Candide

24k64651

answered Mar 16 '12 at 6:22

Candide

24k64651

3

I have the same problem as OP; My problem now is that the event causes now a stack overflow. :

– Malavos
Jan 22 '14 at 12:14

1

Went back to my old project and solved this. Also, I had forgotten to +1 this. This method works quite well! It improve my application loading time on 10seconds or even more, just by using threads to load our localized resources. Cheers!

– Malavos
May 7 '14 at 13:21

3

If I'm not wrong you can't even read a UI object from a non-owner thread; surprised me a bit.

– Elliot
Mar 2 '15 at 9:25

22

Application.Current.Dispatcher.Invoke(MyMethod, DispatcherPriority.ContextIdle); to get the dispatcher if not on the UI thread as per this answer

– JumpingJezza
Aug 21 '15 at 2:59

2

@Candide am still getting this error

– Meer
May 7 '16 at 6:13

|
show 3 more comments

3

I have the same problem as OP; My problem now is that the event causes now a stack overflow. :

– Malavos
Jan 22 '14 at 12:14

1

Went back to my old project and solved this. Also, I had forgotten to +1 this. This method works quite well! It improve my application loading time on 10seconds or even more, just by using threads to load our localized resources. Cheers!

– Malavos
May 7 '14 at 13:21

3

If I'm not wrong you can't even read a UI object from a non-owner thread; surprised me a bit.

– Elliot
Mar 2 '15 at 9:25

22

Application.Current.Dispatcher.Invoke(MyMethod, DispatcherPriority.ContextIdle); to get the dispatcher if not on the UI thread as per this answer

– JumpingJezza
Aug 21 '15 at 2:59

2

@Candide am still getting this error

– Meer
May 7 '16 at 6:13

I have the same problem as OP; My problem now is that the event causes now a stack overflow. :

– Malavos
Jan 22 '14 at 12:14

Went back to my old project and solved this. Also, I had forgotten to +1 this. This method works quite well! It improve my application loading time on 10seconds or even more, just by using threads to load our localized resources. Cheers!

– Malavos
May 7 '14 at 13:21

If I'm not wrong you can't even read a UI object from a non-owner thread; surprised me a bit.

– Elliot
Mar 2 '15 at 9:25

Application.Current.Dispatcher.Invoke(MyMethod, DispatcherPriority.ContextIdle); to get the dispatcher if not on the UI thread as per this answer

– JumpingJezza
Aug 21 '15 at 2:59

@Candide am still getting this error

– Meer
May 7 '16 at 6:13

|
show 3 more comments

Another good use for Dispatcher.Invoke is for immediately updating the UI in a function that performs other tasks:

// Force WPF to render UI changes immediately with this magic line of code...

Dispatcher.Invoke(new Action(() => { }), DispatcherPriority.ContextIdle);

I use this to update button text to "Processing..." and disable it while making WebClient requests.

edited Jan 12 '18 at 4:37

Lauraducky

539823

answered Jun 17 '14 at 19:03

computerGuyCJ

63058

4

This answer is being discussed on Meta. meta.stackoverflow.com/questions/361844/…

– JDB
Jan 12 '18 at 15:56

This stopped my control from getting data from internet?

– user4350912
Mar 6 '18 at 16:50

add a comment |

Another good use for Dispatcher.Invoke is for immediately updating the UI in a function that performs other tasks:

// Force WPF to render UI changes immediately with this magic line of code...

Dispatcher.Invoke(new Action(() => { }), DispatcherPriority.ContextIdle);

I use this to update button text to "Processing..." and disable it while making WebClient requests.

edited Jan 12 '18 at 4:37

Lauraducky

539823

answered Jun 17 '14 at 19:03

computerGuyCJ

63058

4

This answer is being discussed on Meta. meta.stackoverflow.com/questions/361844/…

– JDB
Jan 12 '18 at 15:56

This stopped my control from getting data from internet?

– user4350912
Mar 6 '18 at 16:50

add a comment |

Another good use for Dispatcher.Invoke is for immediately updating the UI in a function that performs other tasks:

// Force WPF to render UI changes immediately with this magic line of code...

Dispatcher.Invoke(new Action(() => { }), DispatcherPriority.ContextIdle);

I use this to update button text to "Processing..." and disable it while making WebClient requests.

edited Jan 12 '18 at 4:37

Lauraducky

539823

answered Jun 17 '14 at 19:03

computerGuyCJ

63058

Another good use for Dispatcher.Invoke is for immediately updating the UI in a function that performs other tasks:

// Force WPF to render UI changes immediately with this magic line of code...

Dispatcher.Invoke(new Action(() => { }), DispatcherPriority.ContextIdle);

I use this to update button text to "Processing..." and disable it while making WebClient requests.

edited Jan 12 '18 at 4:37

Lauraducky

539823

answered Jun 17 '14 at 19:03

computerGuyCJ

63058

edited Jan 12 '18 at 4:37

Lauraducky

539823

edited Jan 12 '18 at 4:37

Lauraducky

539823

edited Jan 12 '18 at 4:37

Lauraducky

539823

answered Jun 17 '14 at 19:03

computerGuyCJ

63058

answered Jun 17 '14 at 19:03

computerGuyCJ

63058

answered Jun 17 '14 at 19:03

computerGuyCJ

63058

4

This answer is being discussed on Meta. meta.stackoverflow.com/questions/361844/…

– JDB
Jan 12 '18 at 15:56

This stopped my control from getting data from internet?

– user4350912
Mar 6 '18 at 16:50

add a comment |

4

This answer is being discussed on Meta. meta.stackoverflow.com/questions/361844/…

– JDB
Jan 12 '18 at 15:56

This stopped my control from getting data from internet?

– user4350912
Mar 6 '18 at 16:50

This answer is being discussed on Meta. meta.stackoverflow.com/questions/361844/…

– JDB
Jan 12 '18 at 15:56

This stopped my control from getting data from internet?

– user4350912
Mar 6 '18 at 16:50

add a comment |

Update

edited Mar 26 at 18:15

answered Oct 21 '15 at 4:31

dotNET

18.3k1387148

4

@l33t: WPF supports multiple UI threads in one application, each of which will have its own Dispatcher. In those cases (which are admittedly rare), calling Control.Dispatcher is the safe approach. For reference you can see this article as well as this SO post (particularly Squidward's answer).

– dotNET
Sep 27 '16 at 10:13

1

Interestingly, I was facing this very exception when I googled and landed on this page and like most of us do, tried the highest voted answer, which didn't solve my issue then. I then found out this reason and posted it here for peer developers.

– dotNET
Sep 27 '16 at 10:15

1

@l33t, if you are using MVVM correctly, then it shouldn't be a problem. The view necessarily know what Dispatcher it is using, whilehe ViewModels and Models know nothing of controls and have no need to know of controls.

– aaronburro
Feb 23 '18 at 14:54

1

@aaronburro: Problem is that VM may want to launch actions on alternate threads (e.g. Tasks, Timer-based actions, Parallel queries), and as the operation progresses, may like to update UI (through RaisePropertyChanged etc), which will in turn try to access a UI control from non-UI thread and thus result in this exception. I don't know of a correct MVVM approach that would solve this problem.

– dotNET
Feb 24 '18 at 8:39

1

The WPF binding engine automatically marshals property change events to the correct Dispatcher. This is why VM has no need to know of the Dispatcher; all it has to do is just raise property changed events. WinForms binding is a different story.

– aaronburro
Aug 17 '18 at 20:31

|
show 15 more comments

Update

edited Mar 26 at 18:15

answered Oct 21 '15 at 4:31

dotNET

18.3k1387148

4

@l33t: WPF supports multiple UI threads in one application, each of which will have its own Dispatcher. In those cases (which are admittedly rare), calling Control.Dispatcher is the safe approach. For reference you can see this article as well as this SO post (particularly Squidward's answer).

– dotNET
Sep 27 '16 at 10:13

1

Interestingly, I was facing this very exception when I googled and landed on this page and like most of us do, tried the highest voted answer, which didn't solve my issue then. I then found out this reason and posted it here for peer developers.

– dotNET
Sep 27 '16 at 10:15

1

@l33t, if you are using MVVM correctly, then it shouldn't be a problem. The view necessarily know what Dispatcher it is using, whilehe ViewModels and Models know nothing of controls and have no need to know of controls.

– aaronburro
Feb 23 '18 at 14:54

1

@aaronburro: Problem is that VM may want to launch actions on alternate threads (e.g. Tasks, Timer-based actions, Parallel queries), and as the operation progresses, may like to update UI (through RaisePropertyChanged etc), which will in turn try to access a UI control from non-UI thread and thus result in this exception. I don't know of a correct MVVM approach that would solve this problem.

– dotNET
Feb 24 '18 at 8:39

1

The WPF binding engine automatically marshals property change events to the correct Dispatcher. This is why VM has no need to know of the Dispatcher; all it has to do is just raise property changed events. WinForms binding is a different story.

– aaronburro
Aug 17 '18 at 20:31

|
show 15 more comments

Update

edited Mar 26 at 18:15

answered Oct 21 '15 at 4:31

dotNET

18.3k1387148

Update

edited Mar 26 at 18:15

answered Oct 21 '15 at 4:31

dotNET

18.3k1387148

edited Mar 26 at 18:15

answered Oct 21 '15 at 4:31

dotNET

18.3k1387148

answered Oct 21 '15 at 4:31

dotNET

18.3k1387148

answered Oct 21 '15 at 4:31

dotNET

18.3k1387148

4

@l33t: WPF supports multiple UI threads in one application, each of which will have its own Dispatcher. In those cases (which are admittedly rare), calling Control.Dispatcher is the safe approach. For reference you can see this article as well as this SO post (particularly Squidward's answer).

– dotNET
Sep 27 '16 at 10:13

1

Interestingly, I was facing this very exception when I googled and landed on this page and like most of us do, tried the highest voted answer, which didn't solve my issue then. I then found out this reason and posted it here for peer developers.

– dotNET
Sep 27 '16 at 10:15

1

@l33t, if you are using MVVM correctly, then it shouldn't be a problem. The view necessarily know what Dispatcher it is using, whilehe ViewModels and Models know nothing of controls and have no need to know of controls.

– aaronburro
Feb 23 '18 at 14:54

1

@aaronburro: Problem is that VM may want to launch actions on alternate threads (e.g. Tasks, Timer-based actions, Parallel queries), and as the operation progresses, may like to update UI (through RaisePropertyChanged etc), which will in turn try to access a UI control from non-UI thread and thus result in this exception. I don't know of a correct MVVM approach that would solve this problem.

– dotNET
Feb 24 '18 at 8:39

1

The WPF binding engine automatically marshals property change events to the correct Dispatcher. This is why VM has no need to know of the Dispatcher; all it has to do is just raise property changed events. WinForms binding is a different story.

– aaronburro
Aug 17 '18 at 20:31

|
show 15 more comments

4

@l33t: WPF supports multiple UI threads in one application, each of which will have its own Dispatcher. In those cases (which are admittedly rare), calling Control.Dispatcher is the safe approach. For reference you can see this article as well as this SO post (particularly Squidward's answer).

– dotNET
Sep 27 '16 at 10:13

1

Interestingly, I was facing this very exception when I googled and landed on this page and like most of us do, tried the highest voted answer, which didn't solve my issue then. I then found out this reason and posted it here for peer developers.

– dotNET
Sep 27 '16 at 10:15

1

@l33t, if you are using MVVM correctly, then it shouldn't be a problem. The view necessarily know what Dispatcher it is using, whilehe ViewModels and Models know nothing of controls and have no need to know of controls.

– aaronburro
Feb 23 '18 at 14:54

1

@aaronburro: Problem is that VM may want to launch actions on alternate threads (e.g. Tasks, Timer-based actions, Parallel queries), and as the operation progresses, may like to update UI (through RaisePropertyChanged etc), which will in turn try to access a UI control from non-UI thread and thus result in this exception. I don't know of a correct MVVM approach that would solve this problem.

– dotNET
Feb 24 '18 at 8:39

1

The WPF binding engine automatically marshals property change events to the correct Dispatcher. This is why VM has no need to know of the Dispatcher; all it has to do is just raise property changed events. WinForms binding is a different story.

– aaronburro
Aug 17 '18 at 20:31

@l33t: WPF supports multiple UI threads in one application, each of which will have its own Dispatcher. In those cases (which are admittedly rare), calling Control.Dispatcher is the safe approach. For reference you can see this article as well as this SO post (particularly Squidward's answer).

– dotNET
Sep 27 '16 at 10:13

Interestingly, I was facing this very exception when I googled and landed on this page and like most of us do, tried the highest voted answer, which didn't solve my issue then. I then found out this reason and posted it here for peer developers.

– dotNET
Sep 27 '16 at 10:15

@l33t, if you are using MVVM correctly, then it shouldn't be a problem. The view necessarily know what Dispatcher it is using, whilehe ViewModels and Models know nothing of controls and have no need to know of controls.

– aaronburro
Feb 23 '18 at 14:54

@aaronburro: Problem is that VM may want to launch actions on alternate threads (e.g. Tasks, Timer-based actions, Parallel queries), and as the operation progresses, may like to update UI (through RaisePropertyChanged etc), which will in turn try to access a UI control from non-UI thread and thus result in this exception. I don't know of a correct MVVM approach that would solve this problem.

– dotNET
Feb 24 '18 at 8:39

The WPF binding engine automatically marshals property change events to the correct Dispatcher. This is why VM has no need to know of the Dispatcher; all it has to do is just raise property changed events. WinForms binding is a different story.

– aaronburro
Aug 17 '18 at 20:31

|
show 15 more comments

If anyone tries to work with BitmapSource in WPF and threads and has this same message: just call Freeze() method first before passing a BitmapSource as a thread parameter.

edited Apr 23 '18 at 8:59

Hakam Fostok

5,72284470

answered Nov 25 '15 at 12:59

juFo

10.9k761110

15

Ah, nothing like a good old vague and mysterious trick to solve something nobody understands.

– Edwin
Mar 4 '17 at 10:43

1

I'd love more information about why this works and how I could have figured it out myself.

– Xavier Shay
Feb 28 '18 at 17:45

@XavierShay docs.microsoft.com/en-us/dotnet/framework/wpf/advanced/…

– juFo
Mar 1 '18 at 10:36

add a comment |

If anyone tries to work with BitmapSource in WPF and threads and has this same message: just call Freeze() method first before passing a BitmapSource as a thread parameter.

edited Apr 23 '18 at 8:59

Hakam Fostok

5,72284470

answered Nov 25 '15 at 12:59

juFo

10.9k761110

15

Ah, nothing like a good old vague and mysterious trick to solve something nobody understands.

– Edwin
Mar 4 '17 at 10:43

1

I'd love more information about why this works and how I could have figured it out myself.

– Xavier Shay
Feb 28 '18 at 17:45

@XavierShay docs.microsoft.com/en-us/dotnet/framework/wpf/advanced/…

– juFo
Mar 1 '18 at 10:36

add a comment |

If anyone tries to work with BitmapSource in WPF and threads and has this same message: just call Freeze() method first before passing a BitmapSource as a thread parameter.

edited Apr 23 '18 at 8:59

Hakam Fostok

5,72284470

answered Nov 25 '15 at 12:59

juFo

10.9k761110

If anyone tries to work with BitmapSource in WPF and threads and has this same message: just call Freeze() method first before passing a BitmapSource as a thread parameter.

edited Apr 23 '18 at 8:59

Hakam Fostok

5,72284470

answered Nov 25 '15 at 12:59

juFo

10.9k761110

edited Apr 23 '18 at 8:59

Hakam Fostok

5,72284470

edited Apr 23 '18 at 8:59

Hakam Fostok

5,72284470

edited Apr 23 '18 at 8:59

Hakam Fostok

5,72284470

answered Nov 25 '15 at 12:59

juFo

10.9k761110

answered Nov 25 '15 at 12:59

juFo

10.9k761110

answered Nov 25 '15 at 12:59

juFo

10.9k761110

15

Ah, nothing like a good old vague and mysterious trick to solve something nobody understands.

– Edwin
Mar 4 '17 at 10:43

1

I'd love more information about why this works and how I could have figured it out myself.

– Xavier Shay
Feb 28 '18 at 17:45

@XavierShay docs.microsoft.com/en-us/dotnet/framework/wpf/advanced/…

– juFo
Mar 1 '18 at 10:36

add a comment |

15

Ah, nothing like a good old vague and mysterious trick to solve something nobody understands.

– Edwin
Mar 4 '17 at 10:43

1

I'd love more information about why this works and how I could have figured it out myself.

– Xavier Shay
Feb 28 '18 at 17:45

@XavierShay docs.microsoft.com/en-us/dotnet/framework/wpf/advanced/…

– juFo
Mar 1 '18 at 10:36

Ah, nothing like a good old vague and mysterious trick to solve something nobody understands.

– Edwin
Mar 4 '17 at 10:43

I'd love more information about why this works and how I could have figured it out myself.

– Xavier Shay
Feb 28 '18 at 17:45

@XavierShay docs.microsoft.com/en-us/dotnet/framework/wpf/advanced/…

– juFo
Mar 1 '18 at 10:36

add a comment |

this happened with me because I tried to access UI component in another thread insted of UI thread

like this

private void button_Click(object sender, RoutedEventArgs e)

{

    new Thread(SyncProcces).Start();

}



private void SyncProcces()

{

    string val1 = null, val2 = null;

    //here is the problem 

    val1 = textBox1.Text;//access UI in another thread

    val2 = textBox2.Text;//access UI in another thread

    localStore = new LocalStore(val1);

    remoteStore = new RemoteStore(val2);

}

to solve this problem, wrap any ui call inside what Candide mentioned above in his answer

private void SyncProcces()

{

    string val1 = null, val2 = null;

    this.Dispatcher.Invoke((Action)(() =>

    {//this refer to form in WPF application 

        val1 = textBox.Text;

        val2 = textBox_Copy.Text;

    }));

    localStore = new LocalStore(val1);

    remoteStore = new RemoteStore(val2 );

}

edited May 23 '17 at 12:02

Community♦

answered Jun 27 '16 at 7:59

Basheer AL-MOMANI

6,98814866

1

Upvoted, because this is not a duplicate answer or plagiaristic, but it instead provides a good example that other answers were lacking, while giving credit for what was posted earlier.

– Panzercrisis
Sep 2 '16 at 15:24

Upvote is for a clear answer. Although same was written by others, but this make it clear for anyone who is stuck.

– NishantM
Mar 4 '17 at 7:11

add a comment |

this happened with me because I tried to access UI component in another thread insted of UI thread

like this

private void button_Click(object sender, RoutedEventArgs e)

{

    new Thread(SyncProcces).Start();

}



private void SyncProcces()

{

    string val1 = null, val2 = null;

    //here is the problem 

    val1 = textBox1.Text;//access UI in another thread

    val2 = textBox2.Text;//access UI in another thread

    localStore = new LocalStore(val1);

    remoteStore = new RemoteStore(val2);

}

to solve this problem, wrap any ui call inside what Candide mentioned above in his answer

private void SyncProcces()

{

    string val1 = null, val2 = null;

    this.Dispatcher.Invoke((Action)(() =>

    {//this refer to form in WPF application 

        val1 = textBox.Text;

        val2 = textBox_Copy.Text;

    }));

    localStore = new LocalStore(val1);

    remoteStore = new RemoteStore(val2 );

}

edited May 23 '17 at 12:02

Community♦

answered Jun 27 '16 at 7:59

Basheer AL-MOMANI

6,98814866

1

Upvoted, because this is not a duplicate answer or plagiaristic, but it instead provides a good example that other answers were lacking, while giving credit for what was posted earlier.

– Panzercrisis
Sep 2 '16 at 15:24

Upvote is for a clear answer. Although same was written by others, but this make it clear for anyone who is stuck.

– NishantM
Mar 4 '17 at 7:11

add a comment |

this happened with me because I tried to access UI component in another thread insted of UI thread

like this

private void button_Click(object sender, RoutedEventArgs e)

{

    new Thread(SyncProcces).Start();

}



private void SyncProcces()

{

    string val1 = null, val2 = null;

    //here is the problem 

    val1 = textBox1.Text;//access UI in another thread

    val2 = textBox2.Text;//access UI in another thread

    localStore = new LocalStore(val1);

    remoteStore = new RemoteStore(val2);

}

to solve this problem, wrap any ui call inside what Candide mentioned above in his answer

private void SyncProcces()

{

    string val1 = null, val2 = null;

    this.Dispatcher.Invoke((Action)(() =>

    {//this refer to form in WPF application 

        val1 = textBox.Text;

        val2 = textBox_Copy.Text;

    }));

    localStore = new LocalStore(val1);

    remoteStore = new RemoteStore(val2 );

}

edited May 23 '17 at 12:02

Community♦

answered Jun 27 '16 at 7:59

Basheer AL-MOMANI

6,98814866

this happened with me because I tried to access UI component in another thread insted of UI thread

like this

private void button_Click(object sender, RoutedEventArgs e)

{

    new Thread(SyncProcces).Start();

}



private void SyncProcces()

{

    string val1 = null, val2 = null;

    //here is the problem 

    val1 = textBox1.Text;//access UI in another thread

    val2 = textBox2.Text;//access UI in another thread

    localStore = new LocalStore(val1);

    remoteStore = new RemoteStore(val2);

}

to solve this problem, wrap any ui call inside what Candide mentioned above in his answer

private void SyncProcces()

{

    string val1 = null, val2 = null;

    this.Dispatcher.Invoke((Action)(() =>

    {//this refer to form in WPF application 

        val1 = textBox.Text;

        val2 = textBox_Copy.Text;

    }));

    localStore = new LocalStore(val1);

    remoteStore = new RemoteStore(val2 );

}

edited May 23 '17 at 12:02

Community♦

answered Jun 27 '16 at 7:59

Basheer AL-MOMANI

6,98814866

edited May 23 '17 at 12:02

Community♦

edited May 23 '17 at 12:02

Community♦

edited May 23 '17 at 12:02

Community♦

answered Jun 27 '16 at 7:59

Basheer AL-MOMANI

6,98814866

answered Jun 27 '16 at 7:59

Basheer AL-MOMANI

6,98814866

answered Jun 27 '16 at 7:59

Basheer AL-MOMANI

6,98814866

1

Upvoted, because this is not a duplicate answer or plagiaristic, but it instead provides a good example that other answers were lacking, while giving credit for what was posted earlier.

– Panzercrisis
Sep 2 '16 at 15:24

Upvote is for a clear answer. Although same was written by others, but this make it clear for anyone who is stuck.

– NishantM
Mar 4 '17 at 7:11

add a comment |

1

Upvoted, because this is not a duplicate answer or plagiaristic, but it instead provides a good example that other answers were lacking, while giving credit for what was posted earlier.

– Panzercrisis
Sep 2 '16 at 15:24

Upvote is for a clear answer. Although same was written by others, but this make it clear for anyone who is stuck.

– NishantM
Mar 4 '17 at 7:11

Upvoted, because this is not a duplicate answer or plagiaristic, but it instead provides a good example that other answers were lacking, while giving credit for what was posted earlier.

– Panzercrisis
Sep 2 '16 at 15:24

Upvote is for a clear answer. Although same was written by others, but this make it clear for anyone who is stuck.

– NishantM
Mar 4 '17 at 7:11

add a comment |

You need to Update in to the UI, So use

Dispatcher.BeginInvoke(new Action(() => {GetGridData(null, 0)}));

edited Mar 5 '13 at 12:02

Taryn♦

193k47295358

answered Mar 5 '13 at 11:27

VikramBose

193110

add a comment |

You need to Update in to the UI, So use

Dispatcher.BeginInvoke(new Action(() => {GetGridData(null, 0)}));

edited Mar 5 '13 at 12:02

Taryn♦

193k47295358

answered Mar 5 '13 at 11:27

VikramBose

193110

add a comment |

You need to Update in to the UI, So use

Dispatcher.BeginInvoke(new Action(() => {GetGridData(null, 0)}));

edited Mar 5 '13 at 12:02

Taryn♦

193k47295358

answered Mar 5 '13 at 11:27

VikramBose

193110

You need to Update in to the UI, So use

Dispatcher.BeginInvoke(new Action(() => {GetGridData(null, 0)}));

edited Mar 5 '13 at 12:02

Taryn♦

193k47295358

answered Mar 5 '13 at 11:27

VikramBose

193110

edited Mar 5 '13 at 12:02

Taryn♦

193k47295358

edited Mar 5 '13 at 12:02

Taryn♦

193k47295358

edited Mar 5 '13 at 12:02

Taryn♦

193k47295358

answered Mar 5 '13 at 11:27

VikramBose

193110

answered Mar 5 '13 at 11:27

VikramBose

193110

answered Mar 5 '13 at 11:27

VikramBose

193110

add a comment |

For some reason Candide's answer didn't build. It was helpful, though, as it led me to find this, which worked perfectly:

System.Windows.Threading.Dispatcher.CurrentDispatcher.Invoke((Action)(() =>

    {

       //your code here...

    }));

answered Jul 12 '15 at 10:44

Sarah

168126

It's possible that you didn't call from the form's class. Either you can grab a reference to the Window, or you can probably use what you suggested.

– Simone
Nov 12 '15 at 11:05

4

If it worked for you, it was unnecessary to use it in the first place. System.Windows.Threading.Dispatcher.CurrentDispatcher is the dispatcher for the current thread. That means if you're on a background thread, it's not going to be the UI thread's dispatcher. To access the UI thread's dispatcher, use System.Windows.Application.Current.Dispatcher.

– Will
Sep 1 '17 at 14:46

add a comment |

For some reason Candide's answer didn't build. It was helpful, though, as it led me to find this, which worked perfectly:

System.Windows.Threading.Dispatcher.CurrentDispatcher.Invoke((Action)(() =>

    {

       //your code here...

    }));

answered Jul 12 '15 at 10:44

Sarah

168126

It's possible that you didn't call from the form's class. Either you can grab a reference to the Window, or you can probably use what you suggested.

– Simone
Nov 12 '15 at 11:05

4

If it worked for you, it was unnecessary to use it in the first place. System.Windows.Threading.Dispatcher.CurrentDispatcher is the dispatcher for the current thread. That means if you're on a background thread, it's not going to be the UI thread's dispatcher. To access the UI thread's dispatcher, use System.Windows.Application.Current.Dispatcher.

– Will
Sep 1 '17 at 14:46

add a comment |

For some reason Candide's answer didn't build. It was helpful, though, as it led me to find this, which worked perfectly:

System.Windows.Threading.Dispatcher.CurrentDispatcher.Invoke((Action)(() =>

    {

       //your code here...

    }));

answered Jul 12 '15 at 10:44

Sarah

168126

For some reason Candide's answer didn't build. It was helpful, though, as it led me to find this, which worked perfectly:

System.Windows.Threading.Dispatcher.CurrentDispatcher.Invoke((Action)(() =>

    {

       //your code here...

    }));

answered Jul 12 '15 at 10:44

Sarah

168126

answered Jul 12 '15 at 10:44

Sarah

168126

answered Jul 12 '15 at 10:44

Sarah

168126

answered Jul 12 '15 at 10:44

Sarah

168126

It's possible that you didn't call from the form's class. Either you can grab a reference to the Window, or you can probably use what you suggested.

– Simone
Nov 12 '15 at 11:05

4

If it worked for you, it was unnecessary to use it in the first place. System.Windows.Threading.Dispatcher.CurrentDispatcher is the dispatcher for the current thread. That means if you're on a background thread, it's not going to be the UI thread's dispatcher. To access the UI thread's dispatcher, use System.Windows.Application.Current.Dispatcher.

– Will
Sep 1 '17 at 14:46

add a comment |

It's possible that you didn't call from the form's class. Either you can grab a reference to the Window, or you can probably use what you suggested.

– Simone
Nov 12 '15 at 11:05

4

If it worked for you, it was unnecessary to use it in the first place. System.Windows.Threading.Dispatcher.CurrentDispatcher is the dispatcher for the current thread. That means if you're on a background thread, it's not going to be the UI thread's dispatcher. To access the UI thread's dispatcher, use System.Windows.Application.Current.Dispatcher.

– Will
Sep 1 '17 at 14:46

It's possible that you didn't call from the form's class. Either you can grab a reference to the Window, or you can probably use what you suggested.

– Simone
Nov 12 '15 at 11:05

If it worked for you, it was unnecessary to use it in the first place. System.Windows.Threading.Dispatcher.CurrentDispatcher is the dispatcher for the current thread. That means if you're on a background thread, it's not going to be the UI thread's dispatcher. To access the UI thread's dispatcher, use System.Windows.Application.Current.Dispatcher.

– Will
Sep 1 '17 at 14:46

add a comment |

answered May 11 '17 at 11:45

Paulus Limma

8516

add a comment |

answered May 11 '17 at 11:45

Paulus Limma

8516

add a comment |

answered May 11 '17 at 11:45

Paulus Limma

8516

answered May 11 '17 at 11:45

Paulus Limma

8516

answered May 11 '17 at 11:45

Paulus Limma

8516

answered May 11 '17 at 11:45

Paulus Limma

8516

answered May 11 '17 at 11:45

Paulus Limma

8516

add a comment |

answered Mar 16 '12 at 6:18

JaredPar

581k12110751354

add a comment |

answered Mar 16 '12 at 6:18

JaredPar

581k12110751354

add a comment |

answered Mar 16 '12 at 6:18

JaredPar

581k12110751354

answered Mar 16 '12 at 6:18

JaredPar

581k12110751354

answered Mar 16 '12 at 6:18

JaredPar

581k12110751354

answered Mar 16 '12 at 6:18

JaredPar

581k12110751354

answered Mar 16 '12 at 6:18

JaredPar

581k12110751354

add a comment |

As mentioned here, Dispatcher.Invoke could freeze the UI. Should use Dispatcher.BeginInvoke instead.

Here is a handy extension class to simplify the checking and calling dispatcher invocation.

Sample usage: (call from WPF window)

this Dispatcher.InvokeIfRequired(new Action(() =>

{

    logTextbox.AppendText(message);

    logTextbox.ScrollToEnd();

}));

Extension class:

using System;

using System.Windows.Threading;



namespace WpfUtility

{

    public static class DispatcherExtension

    {

        public static void InvokeIfRequired(this Dispatcher dispatcher, Action action)

        {

            if (dispatcher == null)

            {

                return;

            }

            if (!dispatcher.CheckAccess())

            {

                dispatcher.BeginInvoke(action, DispatcherPriority.ContextIdle);

                return;

            }

            action();

        }

    }

}

edited Mar 29 '18 at 12:53

answered Mar 28 '18 at 22:23

Jeson Martajaya

4,35563644

add a comment |

As mentioned here, Dispatcher.Invoke could freeze the UI. Should use Dispatcher.BeginInvoke instead.

Here is a handy extension class to simplify the checking and calling dispatcher invocation.

Sample usage: (call from WPF window)

this Dispatcher.InvokeIfRequired(new Action(() =>

{

    logTextbox.AppendText(message);

    logTextbox.ScrollToEnd();

}));

Extension class:

using System;

using System.Windows.Threading;



namespace WpfUtility

{

    public static class DispatcherExtension

    {

        public static void InvokeIfRequired(this Dispatcher dispatcher, Action action)

        {

            if (dispatcher == null)

            {

                return;

            }

            if (!dispatcher.CheckAccess())

            {

                dispatcher.BeginInvoke(action, DispatcherPriority.ContextIdle);

                return;

            }

            action();

        }

    }

}

edited Mar 29 '18 at 12:53

answered Mar 28 '18 at 22:23

Jeson Martajaya

4,35563644

add a comment |

As mentioned here, Dispatcher.Invoke could freeze the UI. Should use Dispatcher.BeginInvoke instead.

Here is a handy extension class to simplify the checking and calling dispatcher invocation.

Sample usage: (call from WPF window)

this Dispatcher.InvokeIfRequired(new Action(() =>

{

    logTextbox.AppendText(message);

    logTextbox.ScrollToEnd();

}));

Extension class:

using System;

using System.Windows.Threading;



namespace WpfUtility

{

    public static class DispatcherExtension

    {

        public static void InvokeIfRequired(this Dispatcher dispatcher, Action action)

        {

            if (dispatcher == null)

            {

                return;

            }

            if (!dispatcher.CheckAccess())

            {

                dispatcher.BeginInvoke(action, DispatcherPriority.ContextIdle);

                return;

            }

            action();

        }

    }

}

edited Mar 29 '18 at 12:53

answered Mar 28 '18 at 22:23

Jeson Martajaya

4,35563644

As mentioned here, Dispatcher.Invoke could freeze the UI. Should use Dispatcher.BeginInvoke instead.

Here is a handy extension class to simplify the checking and calling dispatcher invocation.

Sample usage: (call from WPF window)

this Dispatcher.InvokeIfRequired(new Action(() =>

{

    logTextbox.AppendText(message);

    logTextbox.ScrollToEnd();

}));

Extension class:

using System;

using System.Windows.Threading;



namespace WpfUtility

{

    public static class DispatcherExtension

    {

        public static void InvokeIfRequired(this Dispatcher dispatcher, Action action)

        {

            if (dispatcher == null)

            {

                return;

            }

            if (!dispatcher.CheckAccess())

            {

                dispatcher.BeginInvoke(action, DispatcherPriority.ContextIdle);

                return;

            }

            action();

        }

    }

}

edited Mar 29 '18 at 12:53

answered Mar 28 '18 at 22:23

Jeson Martajaya

4,35563644

edited Mar 29 '18 at 12:53

answered Mar 28 '18 at 22:23

Jeson Martajaya

4,35563644

answered Mar 28 '18 at 22:23

Jeson Martajaya

4,35563644

answered Mar 28 '18 at 22:23

Jeson Martajaya

4,35563644

add a comment |

This works for me.

new Thread(() =>

        {



        Thread.CurrentThread.IsBackground = false;

        Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Background, (SendOrPostCallback)delegate {



          //Your Code here.



        }, null);

        }).Start();

edited Dec 26 '18 at 3:19

answered Jun 15 '18 at 15:41

nPcomp

3,10211929

add a comment |

This works for me.

new Thread(() =>

        {



        Thread.CurrentThread.IsBackground = false;

        Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Background, (SendOrPostCallback)delegate {



          //Your Code here.



        }, null);

        }).Start();

edited Dec 26 '18 at 3:19

answered Jun 15 '18 at 15:41

nPcomp

3,10211929

add a comment |

This works for me.

new Thread(() =>

        {



        Thread.CurrentThread.IsBackground = false;

        Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Background, (SendOrPostCallback)delegate {



          //Your Code here.



        }, null);

        }).Start();

edited Dec 26 '18 at 3:19

answered Jun 15 '18 at 15:41

nPcomp

3,10211929

This works for me.

new Thread(() =>

        {



        Thread.CurrentThread.IsBackground = false;

        Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Background, (SendOrPostCallback)delegate {



          //Your Code here.



        }, null);

        }).Start();

edited Dec 26 '18 at 3:19

answered Jun 15 '18 at 15:41

nPcomp

3,10211929

edited Dec 26 '18 at 3:19

answered Jun 15 '18 at 15:41

nPcomp

3,10211929

answered Jun 15 '18 at 15:41

nPcomp

3,10211929

answered Jun 15 '18 at 15:41

nPcomp

3,10211929

add a comment |

Also, another solution is ensuring your controls are created in UI thread, not by a background worker thread for example.

answered Feb 23 '17 at 8:27

FindOutIslamNow

3561417

add a comment |

Also, another solution is ensuring your controls are created in UI thread, not by a background worker thread for example.

answered Feb 23 '17 at 8:27

FindOutIslamNow

3561417

add a comment |

Also, another solution is ensuring your controls are created in UI thread, not by a background worker thread for example.

answered Feb 23 '17 at 8:27

FindOutIslamNow

3561417

Also, another solution is ensuring your controls are created in UI thread, not by a background worker thread for example.

answered Feb 23 '17 at 8:27

FindOutIslamNow

3561417

answered Feb 23 '17 at 8:27

FindOutIslamNow

3561417

answered Feb 23 '17 at 8:27

FindOutIslamNow

3561417

answered Feb 23 '17 at 8:27

FindOutIslamNow

3561417

add a comment |

I kept getting the error when I added cascading comboboxes to my WPF application, and resolved the error by using this API:

    using System.Windows.Data;



    private readonly object _lock = new object();

    private CustomObservableCollection<string> _myUiBoundProperty;

    public CustomObservableCollection<string> MyUiBoundProperty

    {

        get { return _myUiBoundProperty; }

        set

        {

            if (value == _myUiBoundProperty) return;

            _myUiBoundProperty = value;

            NotifyPropertyChanged(nameof(MyUiBoundProperty));

        }

    }



    public MyViewModelCtor(INavigationService navigationService) 

    {

       // Other code...

       BindingOperations.EnableCollectionSynchronization(AvailableDefectSubCategories, _lock );



    }

answered Jun 15 '18 at 19:00

user8128167

2,82053652

add a comment |

I kept getting the error when I added cascading comboboxes to my WPF application, and resolved the error by using this API:

    using System.Windows.Data;



    private readonly object _lock = new object();

    private CustomObservableCollection<string> _myUiBoundProperty;

    public CustomObservableCollection<string> MyUiBoundProperty

    {

        get { return _myUiBoundProperty; }

        set

        {

            if (value == _myUiBoundProperty) return;

            _myUiBoundProperty = value;

            NotifyPropertyChanged(nameof(MyUiBoundProperty));

        }

    }



    public MyViewModelCtor(INavigationService navigationService) 

    {

       // Other code...

       BindingOperations.EnableCollectionSynchronization(AvailableDefectSubCategories, _lock );



    }

answered Jun 15 '18 at 19:00

user8128167

2,82053652

add a comment |

I kept getting the error when I added cascading comboboxes to my WPF application, and resolved the error by using this API:

    using System.Windows.Data;



    private readonly object _lock = new object();

    private CustomObservableCollection<string> _myUiBoundProperty;

    public CustomObservableCollection<string> MyUiBoundProperty

    {

        get { return _myUiBoundProperty; }

        set

        {

            if (value == _myUiBoundProperty) return;

            _myUiBoundProperty = value;

            NotifyPropertyChanged(nameof(MyUiBoundProperty));

        }

    }



    public MyViewModelCtor(INavigationService navigationService) 

    {

       // Other code...

       BindingOperations.EnableCollectionSynchronization(AvailableDefectSubCategories, _lock );



    }

answered Jun 15 '18 at 19:00

user8128167

2,82053652

I kept getting the error when I added cascading comboboxes to my WPF application, and resolved the error by using this API:

    using System.Windows.Data;



    private readonly object _lock = new object();

    private CustomObservableCollection<string> _myUiBoundProperty;

    public CustomObservableCollection<string> MyUiBoundProperty

    {

        get { return _myUiBoundProperty; }

        set

        {

            if (value == _myUiBoundProperty) return;

            _myUiBoundProperty = value;

            NotifyPropertyChanged(nameof(MyUiBoundProperty));

        }

    }



    public MyViewModelCtor(INavigationService navigationService) 

    {

       // Other code...

       BindingOperations.EnableCollectionSynchronization(AvailableDefectSubCategories, _lock );



    }

answered Jun 15 '18 at 19:00

user8128167

2,82053652

answered Jun 15 '18 at 19:00

user8128167

2,82053652

answered Jun 15 '18 at 19:00

user8128167

2,82053652

answered Jun 15 '18 at 19:00

user8128167

2,82053652

add a comment |

protected by Community♦ Apr 17 '17 at 17:18

This page is only for reference, If you need detailed information, please check here

Search This Blog

Ufyukyu