KeyedCollection debug view doesn't work

[JamesNK]

Description

KeyedCollection abstract base class has a debug proxy defined:

runtime/src/libraries/System.ObjectModel/src/System/Collections/ObjectModel/KeyedCollection.cs

Lines 10 to 14 in 7bb99e9

	[Serializable]
	[DebuggerTypeProxy(typeof(CollectionDebugView<>))]
	[DebuggerDisplay("Count = {Count}")]
	[System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
	public abstract class KeyedCollection<TKey, TItem> : Collection<TItem> where TKey : notnull

However, I don't believe it works correctly because it assumes one open generic type and KeyedCollection has two.

And no debug proxy is used when viewing a type that inherits from KeyedCollection with the debugger:

Reproduction Steps

var c = new MyKeyedCollection();
c.Add(new KeyValuePair<string, string>("Name", "Value"));

internal class MyKeyedCollection : KeyedCollection<string, KeyValuePair<string, string>>
{
    protected override string GetKeyForItem(KeyValuePair<string, string> item)
    {
        return item.Key;
    }
}

Expected behavior

A user-friendly debug view.

Should the debug view be a list or a name/value collection? A list is probably more appropriate.

Actual behavior

Default debug view.

Regression?

No response

Known Workarounds

No response

Configuration

net9.0

Other information

No response

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Issue Details

---

Description

KeyedCollection abstract base class has a debug proxy defined:

runtime/src/libraries/System.ObjectModel/src/System/Collections/ObjectModel/KeyedCollection.cs

Lines 10 to 14 in 7bb99e9

	[Serializable]
	[DebuggerTypeProxy(typeof(CollectionDebugView<>))]
	[DebuggerDisplay("Count = {Count}")]
	[System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
	public abstract class KeyedCollection<TKey, TItem> : Collection<TItem> where TKey : notnull

However, I don't believe it works correctly because it assumes one open generic type and KeyedCollection has two.

No debug proxy is used when viewing a type that inherits from KeyedCollection with the debugger:

Reproduction Steps

var c = new MyKeyedCollection();
c.Add(new KeyValuePair<string, string>("Name", "Value"));

internal class MyKeyedCollection : KeyedCollection<string, KeyValuePair<string, string>>
{
    protected override string GetKeyForItem(KeyValuePair<string, string> item)
    {
        return item.Key;
    }
}

Expected behavior

A user-friendly debug view.

Actual behavior

Default debug view.

Regression?

No response

Known Workarounds

No response

Configuration

net9.0

Other information

No response

Author:	JamesNK
Assignees:	-
Labels:	area-System.Collections, untriaged
Milestone:	-