Add the below code before binding the data to GridView
if (ds.Tables[0].Rows.Count == 0)
{
ds.Tables[0].Rows.Add(ds.Tables[0].NewRow());
grdview.DataSource = ds;
grdview.DataBind();
int columncount = grdview.Rows[0].Cells.Count;
grdview.Rows[0].Cells.Clear();
grdview.Rows[0].Cells.Add(new TableCell());
grdview.Rows[0].Cells[0].ColumnSpan = columncount;
grdview.Rows[0].Cells[0].Text = "No Records Found";
}
else
{
grdview.DataSource = ds.Tables[0];
grdview.DataBind();
}