Hi all,
I'm new to this group.
My update command of Datagrid doesn't work

here is the coding:
-------------------------------------------------------------
public class display : System.Web.UI.Page
    {
        protected System.Web.UI.WebControls.DataGrid DataGrid1;
        RegBLLCom objBLL;

        private string OrderBy
        {
            get
            {
                return ViewState["ORDERBY"] != null ? ViewState["ORDERBY"].ToString():"ASC";
            }
            set
            {
                ViewState["ORDERBY"] = value;
            }
        }

        private void makeConnection()
        {
            objBLL = new RegBLLCom(Config.connect2);
        }

        void Page_Load(object sender, System.EventArgs e)
        {
                makeConnection();
                DataGrid1.DataSource=objBLL.PopulateGrid();;
                DataGrid1.DataBind();
        }

        #region Web Form Designer generated code
        override protected void OnInit(EventArgs e)
        {
            //
            // CODEGEN: This call is required by the ASP.NET Web Form Designer.
            //
            InitializeComponent();
            base.OnInit(e);
        }

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.DataGrid1.CancelCommand += new System.Web.UI.WebControls.DataGridCommandEventHand ler(this.dg_cancel);
            this.DataGrid1.EditCommand += new System.Web.UI.WebControls.DataGridCommandEventHand ler(this.dg_edit);
            this.DataGrid1.SortCommand += new System.Web.UI.WebControls.DataGridSortCommandEvent Handler(this.gd_sort);
            this.DataGrid1.UpdateCommand += new System.Web.UI.WebControls.DataGridCommandEventHand ler(this.dg_Update);
            this.Load += new System.EventHandler(this.Page_Load);

        }
        #endregion

        private void dg_edit(object source, System.Web.UI.WebControls.DataGridCommandEventArgs e)
        {
            DataGrid1.EditItemIndex =(int) e.Item.ItemIndex;
            DataGrid1.DataBind();
        }

        private void dg_cancel(object source, System.Web.UI.WebControls.DataGridCommandEventArgs e)
        {
            DataGrid1.EditItemIndex = -1;
            DataGrid1.DataBind();
        }

        private void dg_Update(object source, System.Web.UI.WebControls.DataGridCommandEventArgs e)
        {
            //makeConnection();
            SqlConnection con = new SqlConnection(Config.connect2);
            string updateCement = "Update sample SET invid=@invid,itemno=@itemno,itemname=@itemname,qua ntity=@quantity WHERE invid=@invid";
            SqlCommand com = new SqlCommand(updateCement,con);
            com.Parameters.Add(new SqlParameter("@invid",SqlDbType.VarChar,50));
            com.Parameters.Add(new SqlParameter("@itemno",SqlDbType.VarChar,50));
            com.Parameters.Add(new SqlParameter("@itemname",SqlDbType.VarChar,50));
            com.Parameters.Add(new SqlParameter("@quantity",SqlDbType.NVarChar,50));
            com.Parameters["@invid"].Value = DataGrid1.DataKeys[(int) e.Item.ItemIndex];
            com.Parameters["@itemno"].Value = ((TextBox) e.Item.Cells[2].Controls[0]).Text;
            com.Parameters["@itemname"].Value = ((TextBox) e.Item.Cells[3].Controls[0]).Text;
            com.Parameters["@quantity"].Value = ((TextBox) e.Item.Cells[4].Controls[0]).Text;
            try
            {
                com.Connection.Open();
                com.ExecuteNonQuery();
                DataGrid1.EditItemIndex = -1;
                DataGrid1.DataSource=objBLL.PopulateGrid();
                DataGrid1.DataBind();
                con.Close();
            }
            catch(Exception x)
            {
                throw x;
            }
}
}
---------------------------------------------------------------
//HTML coding

<%@ Page language="c#" Codebehind="display.aspx.cs" AutoEventWireup="false" Inherits="RND.Registration.display" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
    <HEAD>
        <title>display</title>
        <meta content="Microsoft Visual Studio .NET 7.1" name="GENERATOR">
        <meta content="C#" name="CODE_LANGUAGE">
        <meta content="JavaScript" name="vs_defaultClientScript">
        <meta content="http://schemas.microsoft.com/intellisense/ie5" name="vs_targetSchema">
    </HEAD>
    <body>
        <form id="Form1" method="post" runat="server">
            <table height="200" cellSpacing="0" cellPadding="0" width="300" align="center" border="0">
                <tr vAlign="middle" width="100%">
                    <td vAlign="middle" align="center" width="50%">
                    <asp:datagrid DataKeyField=invid id="DataGrid1" runat="server" Height="161px" Width="251px" AllowSorting="True">
                            <Columns>
                                <asp:EditCommandColumn ButtonType="LinkButton" UpdateText="Update" CancelText="Cancel" EditText="Edit"></asp:EditCommandColumn>
                            </Columns>
                        </asp:datagrid></td>
                </tr>
            </table>
        </form>
    </body>
</HTML>
------------------------------------------------------------------------------------------

Can anyone tell me where's the problem ?
Kindly do respond ASAP.
Thanks,
with warm regards,
S.Chandra Mohan

Whatever happens, happens for good.