List of KeyValuePair to be Distinct
<p>I have a list of KeyValuePair which its values are list too such as</p>

<pre><code>List&lt;KeyValuePair&lt;string, List&lt;string&gt;&gt;&gt; ListX = new List&lt;KeyValuePair&lt;string,List&lt;string&gt;&gt;&gt;();
ListX.Add(new KeyValuePair&lt;string,List&lt;string&gt;&gt;("a",list1));
ListX.Add(new KeyValuePair&lt;string,List&lt;string&gt;&gt;("b",list1));
ListX.Add(new KeyValuePair&lt;string,List&lt;string&gt;&gt;("a",list1));`
</code></pre>

<p>I want the keys of each KeyValuePair in the list to be not duplicated, only the keys, can I use Distinct in this list?</p>

<p>for example I want the third item in the list that has "a" key to be deleted because it's duplicated.</p>