Object reference not set to an instance of an object.

Question

I keep getting ObJect not an instance of an object error on the 4th line.
which is (_selecteedAppointmentRow = (DataSetNumber1.TBL_AppointmentsRow) row.Row;

Here is the whole code.

if (appointmentWithEngineer != null)
{
row = (System.Data.DataRowView)appointmentWithEngineer.DataItem;
_selectedAppointmentRow = (DataSetNumber1.TBL_AppointmentsRow)row.Row;
if (_selectedAppointmentRow == null)
MessageBox.Show("Appointment is null");
}
}

Any help will be appreciated.

Regards

Akhil Garg · Answer

Your DataSetNumber1 is null and you are trying to access row so before that check one null condition. if(DataSetNumber1!=null)

Pankaj Kumar Choudhary · Answer

Not to worry. This is one of the very easiest cases to detect and fix. It simply means that some member/variable of some reference type is dereferenced by using and of its instance (non-static) members which requires this member/variable to be non-null but in fact it appears to be null. Simply execute it under debugger it will stop the execution where the exception is thrown. Put a break point on that line restart the application and come to this point again. Evaluate all references involved in next line and see which one is null while it needs to be not null. After you figure this out fix the code: either make sure the member/variable is properly initialized to a non-null reference or check it for null and in case of null do something else. i think there may be problem in DataSetNumber1.TBL_AppointmentsRow please check either reference of Dataset or table is not null....