title: The given key was not present in the dictionary. Which key?
body: <p>Is there a way to get the value of the given key in the following exception in C# in a way that affects all generic classes? I think this is a big miss in the exception description from Microsoft.</p>
  
  <pre><code>"The given key was not present in the dictionary."
  </code></pre>
  
  <p>A better way would be:</p>
  
  <pre><code>"The given key '" + key.ToString() + "' was not present in the dictionary."
  </code></pre>
  
  <p>Solutions might involve mixins or derived classes maybe.</p>