Online support forum? I thought this was a political discussion forum <g> Thank you, Mike.

>No, you are not a total idiot. Not in general and not in this case. You are learning something new and asking questions when you can't figure something out is rational. I know I have wasted a lot of time not asking questions because of foolish pride.
>
>Before long you will be answering questions much more often than asking them. That's the way online support forums are supposed to work.
>
>
>>I feel like a total idiot. Thank you for catching it.
>>
>>>You haven't instantiated an instance of MyDerivedClass (MyDerivedClass m_DerivedClass = new MyDerivedClass();)
>>>>Hi,
>>>>
>>>>I am having a problem that I will try to present here is a simplified manner:
>>>>
>>>>

>>>>public class MyBaseClass
>>>>{
>>>>    public DataSet myDataSet;
>>>>    
>>>>    public void MyMethod( string cStr )
>>>>    {
>>>>          // do something with the string cStr
>>>>   }
>>>>}
>>>>
>>>>public class MyDerivedClass : MyBaseClass
>>>>{
>>>>               // Nothing is this class, so far
>>>> }
>>>>
>>>>public partial class frmMyForm : Form
>>>>{
>>>>   private string cStr
>>>>   public MyDefirvedClass m_DerivedClass;
>>>>
>>>>   public frmMyForm()
>>>>   {
>>>>         InitializeComponent();
>>>>         m_DerivedClass.MyMethod( cStr );                        //  !!! This where I get error Null Reference
>>>>   }
>>>>
>>>>}
>>>>

>>>>
>>>>Note that the when I type m_DerivedClass in the frmMyForm constructor the intellisense shows the methods (MyMethod among them) of the class MyBaseClass so I know that I have declared "using" correctly. Why do I get the Null Reference on call MyMethod() then?
>>>>
>>>>TIA