//dt = ds.Tables[0].DefaultView.ToTable(true, "ColumnsName");
DataView dv = ds.Tables[0].DefaultView;
DataTable dtDistinct = new DataTable();
dtDistinct = dv.ToTable(true, "ColumnsName");
//dt = ds.Tables[0].DefaultView.ToTable(true, "ColumnsName");
DataView dv = ds.Tables[0].DefaultView;
DataTable dtDistinct = new DataTable();
dtDistinct = dv.ToTable(true, "ColumnsName");