What do we need to get iterator implementation in IDictionary?

[scarletquasar]

What is blocking the following code from being a valid iteration implementation?

public Dictionary<string, object> GetHeaders() 
{
	if (_headers == null) 
	{
		yield return new Dictionary<string, object>();
		yield break;
	}
	
	foreach(var header in _headers) 
	{
		yield return new KeyValuePair<string, object>(header.Key, header.Value);
	}
	
	yield break;
}

Note that Dictionary<TKey, TValue> implements IEnumerable<KeyValuePair<TKey, TValue>>

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Issue Details

---

What is blocking the following code from being a valid iteration implementation?

public Dictionary<string, object> GetHeaders() 
{
	if (_headers == null) 
	{
		yield return new Dictionary<string, object>();
		yield break;
	}
	
	foreach(var header in _headers) 
	{
		yield return new KeyValuePair<string, object>(header.Key, header.Value);
	}
	
	yield break;
}

Note that Dictionary<TKey, TValue> implements IEnumerable<KeyValuePair<TKey, TValue>>

Author:	scarletquasar
Assignees:	-
Labels:	area-System.Collections, untriaged, needs-area-label
Milestone:	-

[huoyaoyuan]

Note that Dictionary<TKey, TValue> implements IEnumerable<KeyValuePair<TKey, TValue>>

You can implicitly convert dictionary to IEnumerbale of KVP, but not in the opposite direction. You need to call ToDictionary on the result IEnumerable<KeyValuePair<TKey, TValue>> at some position.

[huoyaoyuan]

What do we need to get iterator implementation in IDictionary?

More closely to the question, the return type of iterator method should be a type that is implemented by IEnumerable<T> and iteratable, which includes only IEnumerable<U> where T : U, and non-generic IEnumerable (object is not iteratable).

[scarletquasar]

@eiriktsarpalis this is an API proposal, why did you convert that to discussion without asking??

[DaZombieKiller]

You haven't proposed any new APIs here. You'll need to open a new issue following the API proposal template.

[scarletquasar]

You're wrong. If you read carefully you can see that I'm proposing the possibility of creating a iterator to compose a Dictionary object. After reading the api proposal template I decided that it does not fit in my suggestion because the questions are limited.

[eiriktsarpalis]

If you read carefully you can see that I'm proposing the possibility of creating a iterator to compose a Dictionary object

This is not evident at all reading your original post. In any case, iterators are a language feature so I would recommend creating an issue in the https://github.com/dotnet/csharplang repo.