hi,
 please help me to upgrade a row in datagrid using c#.net
i used the code,
public void DataGrid1_Update(object sender,DataGridCommandEventArgs e)
{
SqlConnection con = new SqlConnection("server=localhost;Persist Security Info=False;User ID=sa;password=sa;Initial Catalog=vms_database;Data Source=server0");
SqlCommand cmd =new SqlCommand ("update Admin_ringtone set songname=@songname,code=@code where id=@id",con);

cmd.Parameters.Add(new SqlParameter("@id",SqlDbType.NChar,10));
cmd.Parameters["@id"].Value = DataGrid1.DataKeys[(int)e.Item.ItemIndex];
cmd.Parameters["@id"].Value = ((TextBox)e.Item.Cells[3].Controls[0]).Text;

            cmd.Parameters.Add(new SqlParameter("@songname",SqlDbType.NChar,10));
            cmd.Parameters["@songname"].Value = DataGrid1.DataKeys[(int)e.Item.ItemIndex];
            cmd.Parameters["@songname"].Value = ((TextBox)e.Item.Cells[1].Controls[0]).Text;

            cmd.Parameters.Add(new SqlParameter("@code",SqlDbType.NChar,10));
            cmd.Parameters["@code"].Value = DataGrid1.DataKeys[(int)e.Item.ItemIndex];
            cmd.Parameters["@code"].Value = ((TextBox)e.Item.Cells[2].Controls[0]).Text;


            try
            {

                con.Open();
                cmd.ExecuteNonQuery();
                DataGrid1.EditItemIndex = -1;
                BindGrid();
                con.Close();
                Label1.Text = "Updated";
            }

            catch(SqlException exc)
            {
                Label1.Text = exc.Message;

            }

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but it shows an error,Exception Details: System.InvalidCastException: Specified cast is not valid.
it was working perfect previously.now its not working..
please help


sumith

__________________
sumith