Object reference not set to an instance of an object

Hi
I'm coding something like this.

dsSchedule = new DataSet();
dtSchedule = new DataTable();
dtSchedule.Columns.Add("JulianDate");
dtSchedule.Columns.Add("CalenderDay");
dsSchedule.Tables.Add(dtSchedule);
DataRow drDay = dsSchedule.Tables["dtSchedule"].NewRow();

Does this DataRow need instatiation?? What am I missing here?
What I wanted to do was to build a DataTable dynamically and use it as a source to a DataGrid but this run time error stated in the subject is what I get.

ThanksYou're getting a NulReferenceException because the Tables collection of the DataSet doesn't have a Table named "dtSchedule".

If you want to index the Tables collection by name, you need to create your DataTable with a name:

dtSchedule = new DataTable("dtSchedule");