title: Using dictionary.ContainsValue with tuple as the value
body: <p>I have a dictionary where I am storing a key and 2 values in a tuple like so:</p>
  
  <pre><code>variableDictionary = new Dictionary&lt;string, Tuple&lt;string, string&gt;&gt;();
  </code></pre>
  
  <p>So my dictionary is: <code>key, &lt;value1, value2&gt;</code></p>
  
  <p>I want to check if a value1 is already stored in the dictionary. If my dictionary was string for the key and string for the value I could just use <a href="http://msdn.microsoft.com/en-us/library/a63811ah(v=vs.110).aspx" rel="nofollow">ContainsValue</a>. </p>
  
  <pre><code>bool alreadyStored = variableDictionary.ContainsValue(value1);
  </code></pre>
  
  <p>I'm not sure how to find whether my <em>value1</em> is in the dictionary in the <em>value1</em> part of the tuple regardless of what the <em>value2</em> is. I could create a new tuple and check whether it contains this tuple but I'm not sure how to make it effectively ignore the second value.</p>