title: Using Hashtables/Dictionaries with string keys & Case Insensitive Searching
body: <p>Wondering if this is possible.</p>
  
  <p>We have an 3rd Party library that contains identification information about users...</p>
  
  <p>The main interaction with the library is through a HashTable which is keyed with a string, and returns an Object Graph of information for that key.</p>
  
  <p>The problem is, the key is obviously Case Sensitive, but what we get from the users browser doesn't necessarily match the case... (We often get the key fully lowercase'd)</p>
  
  <p>I'm wondering if it's possible to do a case Insensitive key search against a hashtable.</p>
  
  <p>e.g.</p>
  
  <pre><code>Hashtable ht = new Hashtable();
  ht.Add("MyKey", "Details");
  
  string result = ht["MyKey"];
  string result = ht["MYKEY"];
  string result = ht["mykey"];
  </code></pre>
  
  <p>On the off chance we could submit a support ticket to the company to add this functionality, are there any other DataStructures (i.e. the new generic collections/dictionaries) that support this functionality</p>
  
  <p>Lastly, would it be possible to override the System.String GetHashCode() method, to 
  make all case invariant strings return the same hashcode... e.g. I'm thinking this is a no goer as <code>string</code> is a sealed class</p>
  
  <p>Cheers if anyone has any suggestions</p>