C# inherit from Dictionary, iterate over KeyValuePairs

Question

I have a class that inherits from `Dictionary`. Within an instance method, I want to iterate over all `KeyValuePair`'s. I've tried doing the following: ``` foreach (KeyValuePair pair in base) ``` But this fails with the following error: Use of keyword 'base' is not valid in this context How can I iterate over the `KeyValuePair`'s in an instance method in a class that derives from `Dictionary`? Edit: I found I can do the following: ``` var enumerator = base.GetEnumerator(); while (enumerator.MoveNext()) { KeyValuePair pair = enumerator.Current; } ``` However, I would still like to know if there's a way to do this via a `foreach` loop. Edit: thanks for the advice about not inheriting from `Dictionary`. I'm instead implementing `System.Collections.IEnumerable, ICollection>, IEnumerable>, IDictionary`.

Accepted Answer

First, deriving from the .NET collection classes is generally ill-advised because they don't offer virtual methods for calls not inherited from `object`. This can result in bugs when passing your derived collection in via a base-class reference somewhere. You are better off implementing the `IDictionary` interface and aggregating a `Dictionary<,>` inside your implementation - to which you then forward the appropriate calls. That aside, in your specific case, what you want to do is: ``` foreach( KeyValuePair pair in this ) { /* code here */ } ``` The `base` keyword is primarily used to access specific members of your base class. That's not what you're doing here - you are attempting to iterate over the items of a particular instance ... which is simply the `this` reference.

C# inherit from Dictionary, iterate over KeyValuePairs

Solution

Problem