Mixing
How to release Objects stored in a TreeView from memory?
I use Delphi 7. I create a record that stores info, and using pointers I store that record as an object in a TreeView with more than 100 items.
My problem is, how to release or eliminate all these objects from memory?
type
PMyRec = ^TMyRec;
TMyRec = record
Tipo: string;
parent: string;
end;
var
MyRecPtr: PMyRec;
for x := 1 to 100 do
begin
New(MyRecPtr);
MyRecPtr^.Tipo := '1';
MyRecPtr^.parent := 'paul';
Tree1.Items.AddChildObject(nil, IntToStr(x) + '-NewItem', MyRecPtr);
ListaDePonteiros.Add( MyRecPtr ); // I use a TList to store pointers
ListaDeObjectos.Add( MyRecPtr ); // I use a TList to store Objects
end;
How I try to delete them all:
procedure TForm1.Button2Click(Sender: TObject);
procedure EmptyTList(Var AList: TList);
var
intContador: integer;
begin
for intContador := (AList.Count-1) downto 0 do
begin
if Assigned(AList.Items[intContador]) then
begin
Dispose(AList.Items[intContador]);
AList.Items[intContador] := nil;
AList.Delete(intContador);
end;
end;
end;
begin
if Assigned(MyRecPtr) then
begin
EmptyTList(ListaDePonteiros);
end;
end;
When I delete all items in the TreeView OnDelete event, I have this:
if assigned(Node.Data) then
begin
Dispose(Node.Data);
end;
What I want to do is release all objects from memory!
If I dispose all objects using that list then if I delete any item from the TreeView an invalid pointer error is raised!!
Even with all pointers disposed, MyRecPtr still points to somewhere in memory, and Node.Data too!
object pointers delphi-7 new-operator dispose
edited Jan 2 at 0:36
Remy Lebeau
340k19265459
asked Jan 1 at 23:44
ZinkPTZinkPT
1
add a comment |
I use Delphi 7. I create a record that stores info, and using pointers I store that record as an object in a TreeView with more than 100 items.
My problem is, how to release or eliminate all these objects from memory?
type
PMyRec = ^TMyRec;
TMyRec = record
Tipo: string;
parent: string;
end;
var
MyRecPtr: PMyRec;
for x := 1 to 100 do
begin
New(MyRecPtr);
MyRecPtr^.Tipo := '1';
MyRecPtr^.parent := 'paul';
Tree1.Items.AddChildObject(nil, IntToStr(x) + '-NewItem', MyRecPtr);
ListaDePonteiros.Add( MyRecPtr ); // I use a TList to store pointers
ListaDeObjectos.Add( MyRecPtr ); // I use a TList to store Objects
end;
How I try to delete them all:
procedure TForm1.Button2Click(Sender: TObject);
procedure EmptyTList(Var AList: TList);
var
intContador: integer;
begin
for intContador := (AList.Count-1) downto 0 do
begin
if Assigned(AList.Items[intContador]) then
begin
Dispose(AList.Items[intContador]);
AList.Items[intContador] := nil;
AList.Delete(intContador);
end;
end;
end;
begin
if Assigned(MyRecPtr) then
begin
EmptyTList(ListaDePonteiros);
end;
end;
When I delete all items in the TreeView OnDelete event, I have this:
if assigned(Node.Data) then
begin
Dispose(Node.Data);
end;
What I want to do is release all objects from memory!
If I dispose all objects using that list then if I delete any item from the TreeView an invalid pointer error is raised!!
Even with all pointers disposed, MyRecPtr still points to somewhere in memory, and Node.Data too!
object pointers delphi-7 new-operator dispose
edited Jan 2 at 0:36
Remy Lebeau
340k19265459
asked Jan 1 at 23:44
ZinkPTZinkPT
1
You clearly do not understand how pointers and object ownership work. You need to stop what you are doing and go back to basics.
– Remy Lebeau
Jan 2 at 0:40
so if i use this code is enought to release from memory all obects stored in treeviw? : procedure TForm1.Tree1Deletion(Sender: TObject; Node: TTreeNode); begin if Assigned(Node.Data) then Dispose(PMyRec(Node.Data)); end;
– ZinkPT
Jan 2 at 13:13
add a comment |
I use Delphi 7. I create a record that stores info, and using pointers I store that record as an object in a TreeView with more than 100 items.
My problem is, how to release or eliminate all these objects from memory?
type
PMyRec = ^TMyRec;
TMyRec = record
Tipo: string;
parent: string;
end;
var
MyRecPtr: PMyRec;
for x := 1 to 100 do
begin
New(MyRecPtr);
MyRecPtr^.Tipo := '1';
MyRecPtr^.parent := 'paul';
Tree1.Items.AddChildObject(nil, IntToStr(x) + '-NewItem', MyRecPtr);
ListaDePonteiros.Add( MyRecPtr ); // I use a TList to store pointers
ListaDeObjectos.Add( MyRecPtr ); // I use a TList to store Objects
end;
How I try to delete them all:
procedure TForm1.Button2Click(Sender: TObject);
procedure EmptyTList(Var AList: TList);
var
intContador: integer;
begin
for intContador := (AList.Count-1) downto 0 do
begin
if Assigned(AList.Items[intContador]) then
begin
Dispose(AList.Items[intContador]);
AList.Items[intContador] := nil;
AList.Delete(intContador);
end;
end;
end;
begin
if Assigned(MyRecPtr) then
begin
EmptyTList(ListaDePonteiros);
end;
end;
When I delete all items in the TreeView OnDelete event, I have this:
if assigned(Node.Data) then
begin
Dispose(Node.Data);
end;
What I want to do is release all objects from memory!
If I dispose all objects using that list then if I delete any item from the TreeView an invalid pointer error is raised!!
Even with all pointers disposed, MyRecPtr still points to somewhere in memory, and Node.Data too!
object pointers delphi-7 new-operator dispose
edited Jan 2 at 0:36
Remy Lebeau
340k19265459
asked Jan 1 at 23:44
ZinkPTZinkPT
1
I use Delphi 7. I create a record that stores info, and using pointers I store that record as an object in a TreeView with more than 100 items.
My problem is, how to release or eliminate all these objects from memory?
type
PMyRec = ^TMyRec;
TMyRec = record
Tipo: string;
parent: string;
end;
var
MyRecPtr: PMyRec;
for x := 1 to 100 do
begin
New(MyRecPtr);
MyRecPtr^.Tipo := '1';
MyRecPtr^.parent := 'paul';
Tree1.Items.AddChildObject(nil, IntToStr(x) + '-NewItem', MyRecPtr);
ListaDePonteiros.Add( MyRecPtr ); // I use a TList to store pointers
ListaDeObjectos.Add( MyRecPtr ); // I use a TList to store Objects
end;
How I try to delete them all:
procedure TForm1.Button2Click(Sender: TObject);
procedure EmptyTList(Var AList: TList);
var
intContador: integer;
begin
for intContador := (AList.Count-1) downto 0 do
begin
if Assigned(AList.Items[intContador]) then
begin
Dispose(AList.Items[intContador]);
AList.Items[intContador] := nil;
AList.Delete(intContador);
end;
end;
end;
begin
if Assigned(MyRecPtr) then
begin
EmptyTList(ListaDePonteiros);
end;
end;
When I delete all items in the TreeView OnDelete event, I have this:
if assigned(Node.Data) then
begin
Dispose(Node.Data);
end;
What I want to do is release all objects from memory!
If I dispose all objects using that list then if I delete any item from the TreeView an invalid pointer error is raised!!
Even with all pointers disposed, MyRecPtr still points to somewhere in memory, and Node.Data too!
object pointers delphi-7 new-operator dispose
object pointers delphi-7 new-operator dispose
edited Jan 2 at 0:36
Remy Lebeau
340k19265459
asked Jan 1 at 23:44
ZinkPTZinkPT
1
edited Jan 2 at 0:36
Remy Lebeau
340k19265459
asked Jan 1 at 23:44
ZinkPTZinkPT
1
edited Jan 2 at 0:36
Remy Lebeau
340k19265459
edited Jan 2 at 0:36
Remy Lebeau
340k19265459
edited Jan 2 at 0:36
Remy Lebeau
340k19265459
340k19265459
asked Jan 1 at 23:44
ZinkPTZinkPT
1
asked Jan 1 at 23:44
ZinkPTZinkPT
1
asked Jan 1 at 23:44
ZinkPTZinkPT
1
1
You clearly do not understand how pointers and object ownership work. You need to stop what you are doing and go back to basics.
– Remy Lebeau
Jan 2 at 0:40
so if i use this code is enought to release from memory all obects stored in treeviw? : procedure TForm1.Tree1Deletion(Sender: TObject; Node: TTreeNode); begin if Assigned(Node.Data) then Dispose(PMyRec(Node.Data)); end;
– ZinkPT
Jan 2 at 13:13
add a comment |
You clearly do not understand how pointers and object ownership work. You need to stop what you are doing and go back to basics.
– Remy Lebeau
Jan 2 at 0:40
so if i use this code is enought to release from memory all obects stored in treeviw? : procedure TForm1.Tree1Deletion(Sender: TObject; Node: TTreeNode); begin if Assigned(Node.Data) then Dispose(PMyRec(Node.Data)); end;
– ZinkPT
Jan 2 at 13:13
You clearly do not understand how pointers and object ownership work. You need to stop what you are doing and go back to basics.
– Remy Lebeau
Jan 2 at 0:40
You clearly do not understand how pointers and object ownership work. You need to stop what you are doing and go back to basics.
– Remy Lebeau
Jan 2 at 0:40
so if i use this code is enought to release from memory all obects stored in treeviw? : procedure TForm1.Tree1Deletion(Sender: TObject; Node: TTreeNode); begin if Assigned(Node.Data) then Dispose(PMyRec(Node.Data)); end;
– ZinkPT
Jan 2 at 13:13
so if i use this code is enought to release from memory all obects stored in treeviw? : procedure TForm1.Tree1Deletion(Sender: TObject; Node: TTreeNode); begin if Assigned(Node.Data) then Dispose(PMyRec(Node.Data)); end;
– ZinkPT
Jan 2 at 13:13
add a comment |
1 Answer
1
active
oldest
votes
Your code is crashing because you are freeing the same memory twice, because you have not defined any clear ownership of your record instances.
Your ListaDePonteiros and ListaDeObjectos lists are redundant and can be removed. The TTreeView can be the owner of the records and you can simply Dispose() of them in the TTreeView.OnDeletion event and be done with it 1.
var
MyRecPtr: PMyRec;
for x := 1 to 100 do
begin
New(MyRecPtr);
try
MyRecPtr^.Tipo := '1';
MyRecPtr^.parent := 'paul';
Tree1.Items.AddChildObject(nil, IntToStr(x) + '-NewItem', MyRecPtr);
except
Dispose(MyRecPtr);
raise;
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
Tree1.Items.Clear;
end;
procedure TForm1.Tree1Deletion(Sender: TObject; Node: TTreeNode);
begin
if Assigned(Node.Data) then
Dispose(PMyRec(Node.Data));
end;
Otherwise, if you choose to keep a separate list, keep the ListaDeObjectos list and remove the ListaDePonteiros list (as there is no reason to maintain 2 lists tracking the exact same values). You would just need to decide whether you want ListaDeObjectos or Tree1 to own the records you allocate:
If
ListaDeObjectosis to be the owner, DO NOT callDispose(Node.Data)in theTTreeView.OnDeletionevent.
var
MyRecPtr: PMyRec;
Idx: Integer;
for x := 1 to 100 do
begin
New(MyRecPtr);
try
MyRecPtr^.Tipo := '1';
MyRecPtr^.parent := 'paul';
Idx := ListaDeObjectos.Add(MyRecPtr);
try
Tree1.Items.AddChildObject(nil, IntToStr(x) + '-NewItem', MyRecPtr);
except
ListaDeObjectos.Delete(Idx);
raise;
end;
except
Dispose(MyRecPtr);
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
procedure EmptyTList(AList: TList);
var
intContador: integer;
begin
for intContador := 0 to (AList.Count-1) do
Dispose(PMyRec(AList[intContador]));
AList.Clear;
end;
begin
Tree1.Items.Clear;
EmptyTList(ListaDePonteiros);
end;
If
Tree1is to be the owner, DO NOT callDispose(AList.Items[intContador])inEmptyTList()(in fact, you can get rid ofEmptyTList()altogether and just callListaDeObjectos.Clear()when needed).
var
MyRecPtr: PMyRec;
Node: TNode;
for x := 1 to 100 do
begin
New(MyRecPtr);
try
MyRecPtr^.Tipo := '1';
MyRecPtr^.parent := 'paul';
Node := Tree1.Items.AddChildObject(nil, IntToStr(x) + '-NewItem', MyRecPtr);
except
Dispose(MyRecPtr);
raise;
end;
try
ListaDePonteiros.Add(MyRecPtr);
except
Node.Free;
raise;
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
ListaDePonteiros.Clear;
Tree1.Items.Clear;
end;
procedure TForm1.Tree1Deletion(Sender: TObject; Node: TNode);
begin
if Assigned(Node.Data) then
Dispose(PMyRec(Node.Data));
end;
Either way, when not mass-clearing Tree1 and ListaDeObjectos in one go, consider calling ListaDeObjectos.Remove() in the TTreeView.OnDeletion event to keep Tree1 and ListaDeObjectos in sync when removing individual nodes:
procedure TForm1.Tree1Deletion(Sender: TObject; Node: TNode);
begin
if Assigned(Node.Data) then
begin
// only if the TreeView is the owner...
Dispose(PMyRec(Node.Data));
ListaDeObjectos.Remove(Node.Data);
end;
end;
1. Whenever you do Dispose() your record instance, make sure you type-cast raw pointers to PMyRec or else the compiler will not finalize the record's members correctly, leaking memory.
answered Jan 2 at 1:29
Remy LebeauRemy Lebeau
340k19265459
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
Your code is crashing because you are freeing the same memory twice, because you have not defined any clear ownership of your record instances.
Your ListaDePonteiros and ListaDeObjectos lists are redundant and can be removed. The TTreeView can be the owner of the records and you can simply Dispose() of them in the TTreeView.OnDeletion event and be done with it 1.
var
MyRecPtr: PMyRec;
for x := 1 to 100 do
begin
New(MyRecPtr);
try
MyRecPtr^.Tipo := '1';
MyRecPtr^.parent := 'paul';
Tree1.Items.AddChildObject(nil, IntToStr(x) + '-NewItem', MyRecPtr);
except
Dispose(MyRecPtr);
raise;
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
Tree1.Items.Clear;
end;
procedure TForm1.Tree1Deletion(Sender: TObject; Node: TTreeNode);
begin
if Assigned(Node.Data) then
Dispose(PMyRec(Node.Data));
end;
Otherwise, if you choose to keep a separate list, keep the ListaDeObjectos list and remove the ListaDePonteiros list (as there is no reason to maintain 2 lists tracking the exact same values). You would just need to decide whether you want ListaDeObjectos or Tree1 to own the records you allocate:
If
ListaDeObjectosis to be the owner, DO NOT callDispose(Node.Data)in theTTreeView.OnDeletionevent.
var
MyRecPtr: PMyRec;
Idx: Integer;
for x := 1 to 100 do
begin
New(MyRecPtr);
try
MyRecPtr^.Tipo := '1';
MyRecPtr^.parent := 'paul';
Idx := ListaDeObjectos.Add(MyRecPtr);
try
Tree1.Items.AddChildObject(nil, IntToStr(x) + '-NewItem', MyRecPtr);
except
ListaDeObjectos.Delete(Idx);
raise;
end;
except
Dispose(MyRecPtr);
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
procedure EmptyTList(AList: TList);
var
intContador: integer;
begin
for intContador := 0 to (AList.Count-1) do
Dispose(PMyRec(AList[intContador]));
AList.Clear;
end;
begin
Tree1.Items.Clear;
EmptyTList(ListaDePonteiros);
end;
If
Tree1is to be the owner, DO NOT callDispose(AList.Items[intContador])inEmptyTList()(in fact, you can get rid ofEmptyTList()altogether and just callListaDeObjectos.Clear()when needed).
var
MyRecPtr: PMyRec;
Node: TNode;
for x := 1 to 100 do
begin
New(MyRecPtr);
try
MyRecPtr^.Tipo := '1';
MyRecPtr^.parent := 'paul';
Node := Tree1.Items.AddChildObject(nil, IntToStr(x) + '-NewItem', MyRecPtr);
except
Dispose(MyRecPtr);
raise;
end;
try
ListaDePonteiros.Add(MyRecPtr);
except
Node.Free;
raise;
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
ListaDePonteiros.Clear;
Tree1.Items.Clear;
end;
procedure TForm1.Tree1Deletion(Sender: TObject; Node: TNode);
begin
if Assigned(Node.Data) then
Dispose(PMyRec(Node.Data));
end;
Either way, when not mass-clearing Tree1 and ListaDeObjectos in one go, consider calling ListaDeObjectos.Remove() in the TTreeView.OnDeletion event to keep Tree1 and ListaDeObjectos in sync when removing individual nodes:
procedure TForm1.Tree1Deletion(Sender: TObject; Node: TNode);
begin
if Assigned(Node.Data) then
begin
// only if the TreeView is the owner...
Dispose(PMyRec(Node.Data));
ListaDeObjectos.Remove(Node.Data);
end;
end;
1. Whenever you do Dispose() your record instance, make sure you type-cast raw pointers to PMyRec or else the compiler will not finalize the record's members correctly, leaking memory.
answered Jan 2 at 1:29
Remy LebeauRemy Lebeau
340k19265459
add a comment |
Your code is crashing because you are freeing the same memory twice, because you have not defined any clear ownership of your record instances.
Your ListaDePonteiros and ListaDeObjectos lists are redundant and can be removed. The TTreeView can be the owner of the records and you can simply Dispose() of them in the TTreeView.OnDeletion event and be done with it 1.
var
MyRecPtr: PMyRec;
for x := 1 to 100 do
begin
New(MyRecPtr);
try
MyRecPtr^.Tipo := '1';
MyRecPtr^.parent := 'paul';
Tree1.Items.AddChildObject(nil, IntToStr(x) + '-NewItem', MyRecPtr);
except
Dispose(MyRecPtr);
raise;
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
Tree1.Items.Clear;
end;
procedure TForm1.Tree1Deletion(Sender: TObject; Node: TTreeNode);
begin
if Assigned(Node.Data) then
Dispose(PMyRec(Node.Data));
end;
Otherwise, if you choose to keep a separate list, keep the ListaDeObjectos list and remove the ListaDePonteiros list (as there is no reason to maintain 2 lists tracking the exact same values). You would just need to decide whether you want ListaDeObjectos or Tree1 to own the records you allocate:
If
ListaDeObjectosis to be the owner, DO NOT callDispose(Node.Data)in theTTreeView.OnDeletionevent.
var
MyRecPtr: PMyRec;
Idx: Integer;
for x := 1 to 100 do
begin
New(MyRecPtr);
try
MyRecPtr^.Tipo := '1';
MyRecPtr^.parent := 'paul';
Idx := ListaDeObjectos.Add(MyRecPtr);
try
Tree1.Items.AddChildObject(nil, IntToStr(x) + '-NewItem', MyRecPtr);
except
ListaDeObjectos.Delete(Idx);
raise;
end;
except
Dispose(MyRecPtr);
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
procedure EmptyTList(AList: TList);
var
intContador: integer;
begin
for intContador := 0 to (AList.Count-1) do
Dispose(PMyRec(AList[intContador]));
AList.Clear;
end;
begin
Tree1.Items.Clear;
EmptyTList(ListaDePonteiros);
end;
If
Tree1is to be the owner, DO NOT callDispose(AList.Items[intContador])inEmptyTList()(in fact, you can get rid ofEmptyTList()altogether and just callListaDeObjectos.Clear()when needed).
var
MyRecPtr: PMyRec;
Node: TNode;
for x := 1 to 100 do
begin
New(MyRecPtr);
try
MyRecPtr^.Tipo := '1';
MyRecPtr^.parent := 'paul';
Node := Tree1.Items.AddChildObject(nil, IntToStr(x) + '-NewItem', MyRecPtr);
except
Dispose(MyRecPtr);
raise;
end;
try
ListaDePonteiros.Add(MyRecPtr);
except
Node.Free;
raise;
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
ListaDePonteiros.Clear;
Tree1.Items.Clear;
end;
procedure TForm1.Tree1Deletion(Sender: TObject; Node: TNode);
begin
if Assigned(Node.Data) then
Dispose(PMyRec(Node.Data));
end;
Either way, when not mass-clearing Tree1 and ListaDeObjectos in one go, consider calling ListaDeObjectos.Remove() in the TTreeView.OnDeletion event to keep Tree1 and ListaDeObjectos in sync when removing individual nodes:
procedure TForm1.Tree1Deletion(Sender: TObject; Node: TNode);
begin
if Assigned(Node.Data) then
begin
// only if the TreeView is the owner...
Dispose(PMyRec(Node.Data));
ListaDeObjectos.Remove(Node.Data);
end;
end;
1. Whenever you do Dispose() your record instance, make sure you type-cast raw pointers to PMyRec or else the compiler will not finalize the record's members correctly, leaking memory.
answered Jan 2 at 1:29
Remy LebeauRemy Lebeau
340k19265459
add a comment |
Your code is crashing because you are freeing the same memory twice, because you have not defined any clear ownership of your record instances.
Your ListaDePonteiros and ListaDeObjectos lists are redundant and can be removed. The TTreeView can be the owner of the records and you can simply Dispose() of them in the TTreeView.OnDeletion event and be done with it 1.
var
MyRecPtr: PMyRec;
for x := 1 to 100 do
begin
New(MyRecPtr);
try
MyRecPtr^.Tipo := '1';
MyRecPtr^.parent := 'paul';
Tree1.Items.AddChildObject(nil, IntToStr(x) + '-NewItem', MyRecPtr);
except
Dispose(MyRecPtr);
raise;
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
Tree1.Items.Clear;
end;
procedure TForm1.Tree1Deletion(Sender: TObject; Node: TTreeNode);
begin
if Assigned(Node.Data) then
Dispose(PMyRec(Node.Data));
end;
Otherwise, if you choose to keep a separate list, keep the ListaDeObjectos list and remove the ListaDePonteiros list (as there is no reason to maintain 2 lists tracking the exact same values). You would just need to decide whether you want ListaDeObjectos or Tree1 to own the records you allocate:
If
ListaDeObjectosis to be the owner, DO NOT callDispose(Node.Data)in theTTreeView.OnDeletionevent.
var
MyRecPtr: PMyRec;
Idx: Integer;
for x := 1 to 100 do
begin
New(MyRecPtr);
try
MyRecPtr^.Tipo := '1';
MyRecPtr^.parent := 'paul';
Idx := ListaDeObjectos.Add(MyRecPtr);
try
Tree1.Items.AddChildObject(nil, IntToStr(x) + '-NewItem', MyRecPtr);
except
ListaDeObjectos.Delete(Idx);
raise;
end;
except
Dispose(MyRecPtr);
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
procedure EmptyTList(AList: TList);
var
intContador: integer;
begin
for intContador := 0 to (AList.Count-1) do
Dispose(PMyRec(AList[intContador]));
AList.Clear;
end;
begin
Tree1.Items.Clear;
EmptyTList(ListaDePonteiros);
end;
If
Tree1is to be the owner, DO NOT callDispose(AList.Items[intContador])inEmptyTList()(in fact, you can get rid ofEmptyTList()altogether and just callListaDeObjectos.Clear()when needed).
var
MyRecPtr: PMyRec;
Node: TNode;
for x := 1 to 100 do
begin
New(MyRecPtr);
try
MyRecPtr^.Tipo := '1';
MyRecPtr^.parent := 'paul';
Node := Tree1.Items.AddChildObject(nil, IntToStr(x) + '-NewItem', MyRecPtr);
except
Dispose(MyRecPtr);
raise;
end;
try
ListaDePonteiros.Add(MyRecPtr);
except
Node.Free;
raise;
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
ListaDePonteiros.Clear;
Tree1.Items.Clear;
end;
procedure TForm1.Tree1Deletion(Sender: TObject; Node: TNode);
begin
if Assigned(Node.Data) then
Dispose(PMyRec(Node.Data));
end;
Either way, when not mass-clearing Tree1 and ListaDeObjectos in one go, consider calling ListaDeObjectos.Remove() in the TTreeView.OnDeletion event to keep Tree1 and ListaDeObjectos in sync when removing individual nodes:
procedure TForm1.Tree1Deletion(Sender: TObject; Node: TNode);
begin
if Assigned(Node.Data) then
begin
// only if the TreeView is the owner...
Dispose(PMyRec(Node.Data));
ListaDeObjectos.Remove(Node.Data);
end;
end;
1. Whenever you do Dispose() your record instance, make sure you type-cast raw pointers to PMyRec or else the compiler will not finalize the record's members correctly, leaking memory.
answered Jan 2 at 1:29
Remy LebeauRemy Lebeau
340k19265459
Your code is crashing because you are freeing the same memory twice, because you have not defined any clear ownership of your record instances.
Your ListaDePonteiros and ListaDeObjectos lists are redundant and can be removed. The TTreeView can be the owner of the records and you can simply Dispose() of them in the TTreeView.OnDeletion event and be done with it 1.
var
MyRecPtr: PMyRec;
for x := 1 to 100 do
begin
New(MyRecPtr);
try
MyRecPtr^.Tipo := '1';
MyRecPtr^.parent := 'paul';
Tree1.Items.AddChildObject(nil, IntToStr(x) + '-NewItem', MyRecPtr);
except
Dispose(MyRecPtr);
raise;
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
Tree1.Items.Clear;
end;
procedure TForm1.Tree1Deletion(Sender: TObject; Node: TTreeNode);
begin
if Assigned(Node.Data) then
Dispose(PMyRec(Node.Data));
end;
Otherwise, if you choose to keep a separate list, keep the ListaDeObjectos list and remove the ListaDePonteiros list (as there is no reason to maintain 2 lists tracking the exact same values). You would just need to decide whether you want ListaDeObjectos or Tree1 to own the records you allocate:
If
ListaDeObjectosis to be the owner, DO NOT callDispose(Node.Data)in theTTreeView.OnDeletionevent.
var
MyRecPtr: PMyRec;
Idx: Integer;
for x := 1 to 100 do
begin
New(MyRecPtr);
try
MyRecPtr^.Tipo := '1';
MyRecPtr^.parent := 'paul';
Idx := ListaDeObjectos.Add(MyRecPtr);
try
Tree1.Items.AddChildObject(nil, IntToStr(x) + '-NewItem', MyRecPtr);
except
ListaDeObjectos.Delete(Idx);
raise;
end;
except
Dispose(MyRecPtr);
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
procedure EmptyTList(AList: TList);
var
intContador: integer;
begin
for intContador := 0 to (AList.Count-1) do
Dispose(PMyRec(AList[intContador]));
AList.Clear;
end;
begin
Tree1.Items.Clear;
EmptyTList(ListaDePonteiros);
end;
If
Tree1is to be the owner, DO NOT callDispose(AList.Items[intContador])inEmptyTList()(in fact, you can get rid ofEmptyTList()altogether and just callListaDeObjectos.Clear()when needed).
var
MyRecPtr: PMyRec;
Node: TNode;
for x := 1 to 100 do
begin
New(MyRecPtr);
try
MyRecPtr^.Tipo := '1';
MyRecPtr^.parent := 'paul';
Node := Tree1.Items.AddChildObject(nil, IntToStr(x) + '-NewItem', MyRecPtr);
except
Dispose(MyRecPtr);
raise;
end;
try
ListaDePonteiros.Add(MyRecPtr);
except
Node.Free;
raise;
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
ListaDePonteiros.Clear;
Tree1.Items.Clear;
end;
procedure TForm1.Tree1Deletion(Sender: TObject; Node: TNode);
begin
if Assigned(Node.Data) then
Dispose(PMyRec(Node.Data));
end;
Either way, when not mass-clearing Tree1 and ListaDeObjectos in one go, consider calling ListaDeObjectos.Remove() in the TTreeView.OnDeletion event to keep Tree1 and ListaDeObjectos in sync when removing individual nodes:
procedure TForm1.Tree1Deletion(Sender: TObject; Node: TNode);
begin
if Assigned(Node.Data) then
begin
// only if the TreeView is the owner...
Dispose(PMyRec(Node.Data));
ListaDeObjectos.Remove(Node.Data);
end;
end;
1. Whenever you do Dispose() your record instance, make sure you type-cast raw pointers to PMyRec or else the compiler will not finalize the record's members correctly, leaking memory.
answered Jan 2 at 1:29
Remy LebeauRemy Lebeau
340k19265459
answered Jan 2 at 1:29
Remy LebeauRemy Lebeau
340k19265459
answered Jan 2 at 1:29
Remy LebeauRemy Lebeau
340k19265459
answered Jan 2 at 1:29
Remy LebeauRemy Lebeau
340k19265459
340k19265459
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You clearly do not understand how pointers and object ownership work. You need to stop what you are doing and go back to basics.
– Remy Lebeau
Jan 2 at 0:40
so if i use this code is enought to release from memory all obects stored in treeviw? : procedure TForm1.Tree1Deletion(Sender: TObject; Node: TTreeNode); begin if Assigned(Node.Data) then Dispose(PMyRec(Node.Data)); end;
– ZinkPT
Jan 2 at 13:13