ASP.NET

public partial class Default2 : System.Web.UI.Page
{
    SqlConnection cnx = new SqlConnection("Data Source=.\\SQLEXPRESS;AttachDbFilename=|DataDirectory|Coupon Management.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True");
    SqlDataAdapter da1 = new SqlDataAdapter();
    DataSet ds = new DataSet();
    SqlCommand cmd = new SqlCommand();
    DataTable dataTable;

    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {

            FillVendorGrid();

        }
    }

      private void FillVendorGrid()
      {

          dataTable = new DataTable();

          cmd.Connection = cnx;


          cmd.CommandText = "SELECT Coupon_Info.RecievingDate, CouponType.CouponName, Coupon_Info.Serial_Start, Coupon_Info.Serial_End, Coupon_Info.Recieved_By FROM Coupon_Info INNER JOIN CouponType ON Coupon_Info.Coupon_TypeID = CouponType.CouponTypeID";

          da1  = new SqlDataAdapter(cmd);

          da1.Fill(dataTable);
          GridView1.DataSource = dataTable;
          GridView1.DataSource = ds;
          GridView1.DataSourceID = String.Empty;

          //GridView1.DataBind();
         // GridView1.DataSource = ds;
         // GridView1.DataBind();

      }
      protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
      {

        GridView1.PageIndex = e.NewPageIndex;

          FillVendorGrid();

      }
      protected void GridView1_RowDeleting(object sender, GridViewDeleteEventArgs e)
        {

            cmd.Connection = cnx;

            cmd.CommandText = "DELETE FROM Coupon_Info WHERE RecievingDate='" + GridView1.DataKeys[e.RowIndex].Values[0].ToString() + "'";

            cnx.Open();

            cmd.ExecuteNonQuery();

            cnx.Close();

            FillVendorGrid();

        }
}