Quote:
dv.RowFilter = "Deptno=" + comboBox1.SelectedItem;
I suspect that comboBox1 is bound to a datatable; then the SelectedItem will be type System.Data.DataRowView.
The implict conversion of comboBox1.SelectedItem to a string will yield "Deptno=System.Data.DataRowView".
Try:
dv.RowFilter = "Deptno=" + ((DataRowView)ComboBox1.SelectedItem).Row("Your Desired Column").ToString()