ASP.NET

<br />
<script language="javascript" type="text/javascript"><br />
<br />
<br />
function ddl_focus()<br />
{<br />
    if(document.getElementById("<%=DropDownList1.ClientID %>").value=="0")<br />
        {<br />
      <br />
        document.getElementById("<%=DropDownList1.ClientID %>").focus();<br />
       open_ddl();<br />
        }<br />
     <br />
}<br />
<br />
function open_ddl()<br />
{<br />
document.getElementById("<%=DropDownList1.ClientID %>").size=10;<br />
}<br />
<br />
function close_ddl()<br />
{<br />
document.getElementById("<%=DropDownList1.ClientID %>").size=1;<br />
}<br />
 <br />
<br />
</script><br />
<br />

 <asp:scriptmanager id="ScriptManager1" runat="server" xmlns:asp="#unknown">
    </asp:scriptmanager>
    <br />
    <table>
        <tr>
            <td style="width: 461px">

    </td>
            <td style="width: 239px">
            </td>
            <td style="width: 273px">
            </td>
        </tr>
        <tr>
            <td style="width: 461px">
                   
                <asp:dropdownlist id="DropDownList1" onmouseout="return close_ddl();" onmouseover="return open_ddl();" runat="server" width="125px" xmlns:asp="#unknown">
                    <asp:listitem value="0"><Select></asp:listitem>
                    <asp:listitem value="1">Agra</asp:listitem>
                    <asp:listitem value="2">delhi</asp:listitem>
                    <asp:listitem value="3">mumbai</asp:listitem>
                    <asp:listitem value="4">chennai</asp:listitem>
                </asp:dropdownlist>
                <asp:requiredfieldvalidator controltovalidate="DropDownList1" errormessage="RequiredFieldValidator" id="RequiredFieldValidator1" initialvalue="0" runat="server" setfocusonerror="True" xmlns:asp="#unknown">Plz select from ddl</asp:requiredfieldvalidator>
                <asp:updatepanel id="UpdatePanel1" runat="server" updatemode="Conditional" xmlns:asp="#unknown">
                    <contenttemplate>
 <asp:button id="Button1" onclick="Button1_Click" runat="server" text="Button" onclientclick="return ddl_focus();"></asp:button> 
</contenttemplate>
                </asp:updatepanel></td>
            <td style="width: 239px">
            </td>
            <td style="width: 273px">
            </td>
        </tr>
</table>

 protected void gv_RowUpdating1(object sender, GridViewUpdateEventArgs e)
    {
        connectAccessDb();
        int i = e.RowIndex;
        //par = cmd.Parameters;
        //cmd.Parameters.Clear();
        string id = (gv.Rows[e.RowIndex].FindControl("lblCID") as Label).Text;
        string comp = (gv.Rows[e.RowIndex].FindControl("txtCName") as TextBox).Text;
        string address = (gv.Rows[e.RowIndex].FindControl("txtCAddr") as TextBox).Text;
        string city = (gv.Rows[e.RowIndex].FindControl("txtCcity") as TextBox).Text;
        //string strQuery="UPDATE companydetail SET companyname='" + comp + "',companyaddress='" + address + "',companycity='" + city + "' where id=" + Convert.ToInt32(id);
        //dCmd = new OleDbCommand(strQuery, cn);
        //dCmd = new OleDbCommand("UPDATE companydetail SET companyname=@comp, companyaddress=@address, companycity=@city where id=@id", cn);
        string strQuery = "UPDATE companydetail SET companyname=@comp, companyaddress=@address, companycity=@city where id=@id";
        cmd = new OleDbCommand(strQuery, cn);
        cmd.Parameters.Add("@id", OleDbType.Integer).Value = Convert.ToInt32(id);
        cmd.Parameters.Add("@comp", OleDbType.VarChar).Value = comp;
        cmd.Parameters.Add("@address", OleDbType.VarChar).Value = address;
        cmd.Parameters.Add("@city", OleDbType.VarChar).Value = city;

        cmd.ExecuteNonQuery();
        cmd.ExecuteNonQuery();
        //gv.EditIndex = -1;
        cn.Close();
        bindData();

      
    }
 private void bindData()
    {    
        connectAccessDb();
        da = new OleDbDataAdapter("SELECT id,companyname,companyaddress,companycity  from companydetail order by companyname", cn);       
        da.Fill(ds, "companydetail");
        gv.DataSource = ds;
        gv.DataBind();
        cn.Close();        
    }
private void connectAccessDb()
    {

        cn = new OleDbConnection("provider=microsoft.jet.oledb.4.0;data source=" + strRootDir + "App_Data\\newsdb.mdb");
        cn.Open();
    }