title: Linq ExecuteCommand doesn't understand nulls
body: <p>I'm having a problem when passing nulls to a ExecuteCommand() method using linq. My code is similar to the one that follows:</p>
  
  <pre><code>    public void InsertCostumer(string name, int age, string address)
      {
          List&lt;object&gt; myList = new List&lt;object&gt;();
  
          myList.Add(name);
          myList.Add(age);
          myList.Add(address);
  
          StringBuilder queryInsert = new StringBuilder();
          queryInsert.Append("insert into Customers(name, address) values ({0}, {1}, {2})");
  
          this.myDataContext.ExecuteCommand(queryInsert.ToString(), myList.ToArray());
      }
  </code></pre>
  
  <p>But, when a parameter is null (address, for instance), I get the following error: "A query parameter cannot be of type 'System.Object'."</p>
  
  <p>The error doesn't occur if no parameters are null. I know the design in my example is a little poor, I just created a simplified example to focus on the problem. Any suggestions?</p>