<code>IDictionary<TKey, TValue></code> inherits from <code>IEnumerable<KeyValuePair<TKey, TValue>></code>, but <code>IDictionary</code> for some reason doesn't inherit from <code>IEnumerable<DictionaryEntry></code>. I wonder why? I hate to write this ugly <code>.OfType<DictionaryEntry>()</code> every time when I need to make a query against an <code>IDictionary</code>.

Because <code>IDictionary</code> is an older (pre-generics) interface. Changing it would break existing code. It is a legacy. So the underlying issue is why are you (still) using IDictionary based classes, and can't you upgrade?

Why does not IDictionary (non-generic) inherit from IEnumerable<DictionaryEntry>?

Tags:

.net

generics

ienumerable

base-class-library

idictionary

IDictionary<TKey, TValue> inherits from IEnumerable<KeyValuePair<TKey, TValue>>, but IDictionary for some reason doesn't inherit from IEnumerable<DictionaryEntry>. I wonder why? I hate to write this ugly .OfType<DictionaryEntry>() every time when I need to make a query against an IDictionary.