title: make IntPtr in C#.NET point to string value
body: <p>I am using a class which has <code>StringHandle</code> field which is an <code>IntPtr</code> value that represents a
  <code>LPCWSTR</code> in C++. </p>
  
  <pre><code>internal IntPtr StringHandle; // LPCWSTR
  </code></pre>
  
  <p>say now that I have a String: <code>string x = "abcdefg"</code></p>
  
  <p>How can I use the String handle to point to the beginning of the String so that it is like C++ LPCWSTR ?</p>