ASP.NET

protected void Update(object source, DataListCommandEventArgs e)
   {
       int ProductID = Convert.ToInt32(DataList1.DataKeys[e.Item.ItemIndex]);
       TextBox txtqty;
       txtqty = ((TextBox)e.Item.FindControl("txtqty"));
       string connectionstring = ConfigurationManager.ConnectionStrings["SilverOnline"].ConnectionString;
       SqlConnection conn = new SqlConnection(connectionstring);
       SqlCommand cmd = new SqlCommand("Update Home Set ProductQty=@productqty Where ProductID=@productid", conn);
       cmd.Parameters.Add("@productqty", SqlDbType.VarChar).Value = txtqty.Text;
       cmd.Parameters.Add("@productid", SqlDbType.Int).Value = ProductID;
       if (conn.State == ConnectionState.Closed)
           conn.Open();
       cmd.ExecuteNonQuery();
       if (conn.State == ConnectionState.Open)
           conn.Close();
       DataList1.EditItemIndex = -1;
      // Bindlist();
       Session["cart"] = dt;
       DataList1.DataSource = dt;
       DataList1.DataBind();
       lbltotal.Text = "Rs." + gettotal();
       }