Thank you for your kind words of support :)

>It took you long enough to join the club :o) Now you know how the rest of us feel at times... :o)
>
>
>>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