What are ways of distinguishing objects of the same type for retrieval, comparison, etc in c#

I apologize for the strange title, I wasn't sure how to ask the question, so If you have any suggestion as to what would be more appropriate, let me know and I'll update it.

Often when programming, I would use Enums as keys to dictionaries whos values are data relating to the enum. I'd usually do this before I realize that there would be lots of data associated with that enum, which would then lead me on to create a data type.

For example, I might have the enum:

public enum AreaKey

{

    Home,

    Hospital,

    Park,

    TrainStation

}

and then a dictionary (Vector2 being a class with 2 integers):

Dictionary<AreaKey, Vector2> areaCoordinatesByAreaKey;

Later down the line, I decide I want a bunch of other data associated with this area, so instead I build a new class called:

    public class Area

    {

        Vector2 coordinates;

        string name;

        // more data

    }

Now, to reference this data, I know I can just build a dictionary using the same enum as the key to retrieve the specified area, but this always feels cumbersome to me, and almost like it's not proper OOP.

I have the area objects. They have specific data that should make them unique from one and other. Why do I have to use an enum? Also I don't like having to break OCP everytime I realize I need a new area. It would be awesome to just be able to create an object and not have to worry about external management. order 1 retrieval is nice though.

Of course I could use a string key to retrieve it, but that means people have to know the strings and it's not very type safe... enums are easy to read. Help me stack overflow!

asked Nov 21 '18 at 23:16

Sebastian King

646

1

It largely depends on how you want to use them. Having a dictionary of Area objects keyed by AreaKey seems a little odd, because you will only ever have one area of each type.

– Evan Trimboli
Nov 21 '18 at 23:20

1

This is unnecessary obfuscation. What's wrong with a normal class/instance with properties? They read like a charm. "Why do I have to use an enum?"... for this, you don't. I don't understand why you ever did.

– spender
Nov 21 '18 at 23:30

I assume the use of enum stems from something related to "people have to know the strings". There's a whole part to this problem that you haven't really written about, which is how you got here in the first place (I imagine that it's some piece of UI from which users submit data).

– spender
Nov 21 '18 at 23:33

Using a Dictionary that could only ever store 4 objects is a heavy code smell. Hard to guess how this happened, brain-bugs tend to be hard to identify from a code snippet. You're only half-way discovering that something went wrong, think some more.about object identity.

– Hans Passant
Nov 21 '18 at 23:38

I think it might be related to the fact that we use singletons a lot in our code (not me personally, our team). The singleton would contain a bunch of data (like the Areas) and we would need to retrieve the areas, so we would use dictionaries with the enum key... Could this be related?

– Sebastian King
Nov 21 '18 at 23:41

|
show 6 more comments

I apologize for the strange title, I wasn't sure how to ask the question, so If you have any suggestion as to what would be more appropriate, let me know and I'll update it.

For example, I might have the enum:

public enum AreaKey

{

    Home,

    Hospital,

    Park,

    TrainStation

}

and then a dictionary (Vector2 being a class with 2 integers):

Dictionary<AreaKey, Vector2> areaCoordinatesByAreaKey;

Later down the line, I decide I want a bunch of other data associated with this area, so instead I build a new class called:

    public class Area

    {

        Vector2 coordinates;

        string name;

        // more data

    }

Of course I could use a string key to retrieve it, but that means people have to know the strings and it's not very type safe... enums are easy to read. Help me stack overflow!

asked Nov 21 '18 at 23:16

Sebastian King

646

1

It largely depends on how you want to use them. Having a dictionary of Area objects keyed by AreaKey seems a little odd, because you will only ever have one area of each type.

– Evan Trimboli
Nov 21 '18 at 23:20

1

This is unnecessary obfuscation. What's wrong with a normal class/instance with properties? They read like a charm. "Why do I have to use an enum?"... for this, you don't. I don't understand why you ever did.

– spender
Nov 21 '18 at 23:30

I assume the use of enum stems from something related to "people have to know the strings". There's a whole part to this problem that you haven't really written about, which is how you got here in the first place (I imagine that it's some piece of UI from which users submit data).

– spender
Nov 21 '18 at 23:33

Using a Dictionary that could only ever store 4 objects is a heavy code smell. Hard to guess how this happened, brain-bugs tend to be hard to identify from a code snippet. You're only half-way discovering that something went wrong, think some more.about object identity.

– Hans Passant
Nov 21 '18 at 23:38

I think it might be related to the fact that we use singletons a lot in our code (not me personally, our team). The singleton would contain a bunch of data (like the Areas) and we would need to retrieve the areas, so we would use dictionaries with the enum key... Could this be related?

– Sebastian King
Nov 21 '18 at 23:41

|
show 6 more comments

I apologize for the strange title, I wasn't sure how to ask the question, so If you have any suggestion as to what would be more appropriate, let me know and I'll update it.

For example, I might have the enum:

public enum AreaKey

{

    Home,

    Hospital,

    Park,

    TrainStation

}

and then a dictionary (Vector2 being a class with 2 integers):

Dictionary<AreaKey, Vector2> areaCoordinatesByAreaKey;

Later down the line, I decide I want a bunch of other data associated with this area, so instead I build a new class called:

    public class Area

    {

        Vector2 coordinates;

        string name;

        // more data

    }

Of course I could use a string key to retrieve it, but that means people have to know the strings and it's not very type safe... enums are easy to read. Help me stack overflow!

asked Nov 21 '18 at 23:16

Sebastian King

646

I apologize for the strange title, I wasn't sure how to ask the question, so If you have any suggestion as to what would be more appropriate, let me know and I'll update it.

For example, I might have the enum:

public enum AreaKey

{

    Home,

    Hospital,

    Park,

    TrainStation

}

and then a dictionary (Vector2 being a class with 2 integers):

Dictionary<AreaKey, Vector2> areaCoordinatesByAreaKey;

Later down the line, I decide I want a bunch of other data associated with this area, so instead I build a new class called:

    public class Area

    {

        Vector2 coordinates;

        string name;

        // more data

    }

Of course I could use a string key to retrieve it, but that means people have to know the strings and it's not very type safe... enums are easy to read. Help me stack overflow!

c# oop object enums ocp

asked Nov 21 '18 at 23:16

Sebastian King

646

asked Nov 21 '18 at 23:16

Sebastian King

646

asked Nov 21 '18 at 23:16

Sebastian King

646

asked Nov 21 '18 at 23:16

Sebastian King

646

asked Nov 21 '18 at 23:16

Sebastian King

646

1

It largely depends on how you want to use them. Having a dictionary of Area objects keyed by AreaKey seems a little odd, because you will only ever have one area of each type.

– Evan Trimboli
Nov 21 '18 at 23:20

1

This is unnecessary obfuscation. What's wrong with a normal class/instance with properties? They read like a charm. "Why do I have to use an enum?"... for this, you don't. I don't understand why you ever did.

– spender
Nov 21 '18 at 23:30

I assume the use of enum stems from something related to "people have to know the strings". There's a whole part to this problem that you haven't really written about, which is how you got here in the first place (I imagine that it's some piece of UI from which users submit data).

– spender
Nov 21 '18 at 23:33

Using a Dictionary that could only ever store 4 objects is a heavy code smell. Hard to guess how this happened, brain-bugs tend to be hard to identify from a code snippet. You're only half-way discovering that something went wrong, think some more.about object identity.

– Hans Passant
Nov 21 '18 at 23:38

I think it might be related to the fact that we use singletons a lot in our code (not me personally, our team). The singleton would contain a bunch of data (like the Areas) and we would need to retrieve the areas, so we would use dictionaries with the enum key... Could this be related?

– Sebastian King
Nov 21 '18 at 23:41

|
show 6 more comments

1

It largely depends on how you want to use them. Having a dictionary of Area objects keyed by AreaKey seems a little odd, because you will only ever have one area of each type.

– Evan Trimboli
Nov 21 '18 at 23:20

1

This is unnecessary obfuscation. What's wrong with a normal class/instance with properties? They read like a charm. "Why do I have to use an enum?"... for this, you don't. I don't understand why you ever did.

– spender
Nov 21 '18 at 23:30

I assume the use of enum stems from something related to "people have to know the strings". There's a whole part to this problem that you haven't really written about, which is how you got here in the first place (I imagine that it's some piece of UI from which users submit data).

– spender
Nov 21 '18 at 23:33

Using a Dictionary that could only ever store 4 objects is a heavy code smell. Hard to guess how this happened, brain-bugs tend to be hard to identify from a code snippet. You're only half-way discovering that something went wrong, think some more.about object identity.

– Hans Passant
Nov 21 '18 at 23:38

I think it might be related to the fact that we use singletons a lot in our code (not me personally, our team). The singleton would contain a bunch of data (like the Areas) and we would need to retrieve the areas, so we would use dictionaries with the enum key... Could this be related?

– Sebastian King
Nov 21 '18 at 23:41

It largely depends on how you want to use them. Having a dictionary of Area objects keyed by AreaKey seems a little odd, because you will only ever have one area of each type.

– Evan Trimboli
Nov 21 '18 at 23:20

This is unnecessary obfuscation. What's wrong with a normal class/instance with properties? They read like a charm. "Why do I have to use an enum?"... for this, you don't. I don't understand why you ever did.

– spender
Nov 21 '18 at 23:30

I assume the use of enum stems from something related to "people have to know the strings". There's a whole part to this problem that you haven't really written about, which is how you got here in the first place (I imagine that it's some piece of UI from which users submit data).

– spender
Nov 21 '18 at 23:33

Using a Dictionary that could only ever store 4 objects is a heavy code smell. Hard to guess how this happened, brain-bugs tend to be hard to identify from a code snippet. You're only half-way discovering that something went wrong, think some more.about object identity.

– Hans Passant
Nov 21 '18 at 23:38

I think it might be related to the fact that we use singletons a lot in our code (not me personally, our team). The singleton would contain a bunch of data (like the Areas) and we would need to retrieve the areas, so we would use dictionaries with the enum key... Could this be related?

– Sebastian King
Nov 21 '18 at 23:41

|
show 6 more comments

1 Answer
1

active

oldest

votes

It totally depends on how you intend to retrieve the object. For example typically when creating WinForms apps (before I knew about the magic of data binding) and I have added items to say a ListBox, I might want to remember each object's position in the list so that I can retrieve it easily later. I would create Dictionary<Foo, int>. Similarly, I may want to allow quick lookup based on the position in the list so I would have a Dictionary<int, Foo>. In other words don't try to store everything into one Dictionary<>. Define them by use case.

You have already defined one by AreaKey and this assumes no two objects have the same enum and so using a dictionary in this case makes sense. However, I think you are going down the wrong track trying to put everything into one key. Instead you might want to have another Dictionary<string, Area> where it refers to the Area.name so that not only can you lookup by enum, but also by name.

Later you might want to add PostCode so again another Dictionary<int, Area> makes sense.

In summary, define:

Dictionary<string, Area> mapAreasByName;

Dictionary<int, Area> mapAreasByPostCode;



var area = mapAreasByName["New York"];

area = mapAreasByPostCode[2000];

edited Nov 22 '18 at 2:00

answered Nov 21 '18 at 23:44

MickyD

10.7k63352

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Later you might want to add PostCode so again another Dictionary<int, Area> makes sense.

In summary, define:

Dictionary<string, Area> mapAreasByName;

Dictionary<int, Area> mapAreasByPostCode;



var area = mapAreasByName["New York"];

area = mapAreasByPostCode[2000];

edited Nov 22 '18 at 2:00

answered Nov 21 '18 at 23:44

MickyD

10.7k63352

add a comment |

Later you might want to add PostCode so again another Dictionary<int, Area> makes sense.

In summary, define:

Dictionary<string, Area> mapAreasByName;

Dictionary<int, Area> mapAreasByPostCode;



var area = mapAreasByName["New York"];

area = mapAreasByPostCode[2000];

edited Nov 22 '18 at 2:00

answered Nov 21 '18 at 23:44

MickyD

10.7k63352

add a comment |

Later you might want to add PostCode so again another Dictionary<int, Area> makes sense.

In summary, define:

Dictionary<string, Area> mapAreasByName;

Dictionary<int, Area> mapAreasByPostCode;



var area = mapAreasByName["New York"];

area = mapAreasByPostCode[2000];

edited Nov 22 '18 at 2:00

answered Nov 21 '18 at 23:44

MickyD

10.7k63352

Later you might want to add PostCode so again another Dictionary<int, Area> makes sense.

In summary, define:

Dictionary<string, Area> mapAreasByName;

Dictionary<int, Area> mapAreasByPostCode;



var area = mapAreasByName["New York"];

area = mapAreasByPostCode[2000];

edited Nov 22 '18 at 2:00

answered Nov 21 '18 at 23:44

MickyD

10.7k63352

edited Nov 22 '18 at 2:00

answered Nov 21 '18 at 23:44

MickyD

10.7k63352

answered Nov 21 '18 at 23:44

MickyD

10.7k63352

answered Nov 21 '18 at 23:44

MickyD

10.7k63352

add a comment |

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