C#-WEB: DetailsView, ModeChanging, and checking for data changes

[ledneh]

I've been working on concurrency checking for an application I'm building, and a minor part of it has me slightly stumped.


I've got a DetailsView that populates from an ObjectDataSourc e, using business objects with optimistic concurrency checking built in in my Save() method (against a timestamp column). This can be proven to work perfectly in the following scenario:

- Start app, go to the DetailsView page (defaults to readonly), open a new window

- In one window, go to Update mode

- In the other window, go to Update mode, make a change, click Update

- In the first window, make a change and click update

This will cause my code to generate a DBConcurrencyEx ception. All well and good. However, take the following scenario:

- Start app, go to DetailsView page, open a new window

- In one window, go to update mode, make a change, click update

- In the other window, go to Update mode

You will ender Update mode with the changed data. Now, technically, this works, however when this happens (data changed between the time it was opened for reading and the time it was opened for writing) I want to alert the user.

My first thought is to add something to the ModeChanged event for the DetailsView, but what to add to do the checking I am unsure about. Does anyone have any advice here?

Thanks!



Here's the relevant code.


EventDetails.as px

1 <%@ Page Language="C#" MasterPageFile= "~/MasterPage.mast er" AutoEventWireup ="true" CodeFile="Event Details.aspx.cs " Inherits="Event Details" Title="Untitled Page" %>
2 <asp:Content ID="Content1" ContentPlaceHol derID="ContentP laceHolder1" Runat="Server">
3 <asp:DetailsVie w ID="DetailsView 1" runat="server" Height="50px" Style="position : relative"
4 Width="125px" OnModeChanging= "DetailsView1_M odeChanging" AutoGenerateRow s="False" DataSourceID="O bjectDataSource 1" DataKeyNames="I D,Timestamp">
5 <Fields>
6 <asp:BoundFie ld DataField="Titl e" HeaderText="Tit le" SortExpression= "Title" />
7 <asp:BoundFie ld DataField="Star tDateTime" HeaderText="Sta rtDateTime" SortExpression= "StartDateT ime" />
8 <asp:BoundFie ld DataField="EndD ateTime" HeaderText="End DateTime" SortExpression= "EndDateTim e" />
9 <asp:BoundFie ld DataField="Desc ription" HeaderText="Des cription" SortExpression= "Descriptio n" />
10 <asp:CommandFie ld ShowEditButton= "True" />
11 </Fields>
12
13 </asp:DetailsView >
14 <asp:ObjectData Source ID="ObjectDataS ource1" runat="server" DataObjectTypeN ame="BSC.PID.BO .CalendarEvent"
15 SelectMethod="G etEvent" TypeName="BSC.P ID.BLL.Calendar EventManager" UpdateMethod="S ave">
16 <SelectParamete rs>
17 <asp:QueryStrin gParameter Name="id" QueryStringFiel d="id" Type="Int32" />
18 </SelectParameter s>
19 </asp:ObjectDataS ource>
20 </asp:Content>
21
22



EventDetails.as px.cs



1 using System;
2 using System.Data;
3 using System.Configur ation;
4 using System.Collecti ons;
5 using System.Web;
6 using System.Web.Secu rity;
7 using System.Web.UI;
8 using System.Web.UI.W ebControls;
9 using System.Web.UI.W ebControls.WebP arts;
10 using System.Web.UI.H tmlControls;
11
12 using BSC.PID.BO;
13 using BSC.PID.BLL;
14
15 public partial class EventDetails : System.Web.UI.P age
16 {
17 protected void Page_Load(objec t sender, EventArgs e)
18 {
19
20 }
21 protected void DetailsView1_Mo deChanging(obje ct sender, DetailsViewMode EventArgs e)
22 {
23
24 }
25 }
26

[ledneh]

Bump for the new day. Anyone?