title: Sorting a list of strings in a very specific order
body: <p>This is my class:</p>
  
  <pre><code>class Example {
      string GridValue;
  }
  </code></pre>
  
  <p>In my code, i use a List that I want to sort.
  Let's say that this List has the following values:</p>
  
  <pre><code>{
      "P", 
      "Q", 
      "X", 
      "H", 
      "J", 
      "L"
  }
  </code></pre>
  
  <p>And this is the output I expect after calling Sort():</p>
  
  <pre><code>{
      "X", 
      "Q", 
      "L", 
      "H", 
      "P", 
      "J"
  }
  </code></pre>
  
  <p>How can I achieve this using the IComparer interface?</p>
  
  <p>Thanks!</p>