ASP.NET

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

private   Code.BL.Users.SysUserCollection users = new Code.BL.Users.SysUserCollection();
    public  Code.BL.Users.SysUserCollection OnLineUsers
    {
        get { return users; }
        set { users = value; }
    }

public class SysUserCollection : IList<SysUser>
   {


       List<SysUser> users = new List<SysUser>();

       #region IList<SysUser> Members

       public int IndexOf(SysUser item)
       {
          return users.IndexOf(item);
       }

       public void Insert(int index, SysUser item)
       {
           throw new Exception("The method or operation is not implemented.");
       }

       public void RemoveAt(int index)
       {
           users.RemoveAt(index);
       }

       public SysUser this[int index]
       {
           get
           {
               return users[index];
           }
           set
           {
               users[index] = value;
           }
       }

       #endregion

       #region ICollection<SysUser> Members

       public void Add(SysUser item)
       {
           if (!this.Contains(item))
           {
               users.Add(item);

           }

       }

       public void Clear()
       {
           users.Clear();
       }

       public bool Contains(SysUser item)
       {
           foreach (SysUser user in users)
           {
               if (user.UserId == item.UserId)
                   return true;
           }
           return false;
       }

       public void CopyTo(SysUser[] array, int arrayIndex)
       {
           throw new Exception("The method or operation is not implemented.");
       }

       public int Count
       {
           get { return users.Count; }
       }

       public bool IsReadOnly
       {
           get { throw new Exception("The method or operation is not implemented."); }
       }

       public bool Remove(SysUser item)
       {
           foreach (SysUser user in users)
           {
               if (user.UserId == item.UserId)
               {
                   return users.Remove(user);
               }
           }
        return false;
       }

       #endregion

       #region IEnumerable<SysUser> Members

       public IEnumerator<SysUser> GetEnumerator()
       {
           return users.GetEnumerator();
       }

       #endregion

       #region IEnumerable Members

       IEnumerator IEnumerable.GetEnumerator()
       {
           throw new Exception("The method or operation is not implemented.");
       }

       #endregion
   }

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();

        }
}