C# LINQ query a Dictionary
<p>I have a C# dictionary:</p>
<pre><code>Dictionary&lt;int, ItemsClass&gt; Items
</code></pre>
<p><code>ItemsClass</code> has a member called <code>Number</code></p>
<p>I want to write a LINQ query that returns me the Dictionary key number for the <code>ItemsClass</code> that has a <code>Number</code> matching a certain value e.g. x.</p>
<p>How can I do this?</p>