protected void gvSub_RowEditing(object sender, GridViewEditEventArgs e)
{
    GridView gvSub = sender as GridView;
    GridViewRow row = gvSub.Rows[e.NewEditIndex];

    Int32 a = Convert.ToInt32(gvSub.DataKeys[e.NewEditIndex][0]);
    TextBox1.Text = ((Label)row.FindControl("lblName")).Text;
    TextBox2.Text = ((Label)row.FindControl("lblPrice")).Text;
    TextBox3.Text = ((Label)row.FindControl("qty")).Text;

    String Cate = ((Label)gvSub.Parent.FindControl("lblCtName")).Text;
    DropDownList1.Items.FindByValue(Cate.ToString()).Selected = true;

    btnSub.Text = "Update";
    e.Cancel = true;
}