title: DBNull.Value as optional parameter
body: <p>Is is possible to pass DBNull.Value as optional parameter?
  I tried in C# </p>
  
  <pre><code>private void CallSP(string param0, string param2 = DBNull.Value)
  {
  }
  </code></pre>
  
  <p>Its is giving error. I need to call a Stored procedure in this method, so i am passing DBNull.Value. 
  Is'DBNull.Value' and 'null' are treated as same in SQL Server? Shall i pass 'null' instead of 'DBNull.Value'???</p>