Asp.NET用户控件回发问题

Question

I have a aspx page that has a Tab control, a few buttons and a User Control on it.

<dx:TabPage Text="Worker Information" Name="tabWorker">
    <ContentCollection>
        <dx:ContentControl runat="server" SupportsDisabledAttribute="True">
            <uc:WorkerInfo runat="server" OnWorkerLoaded="On_Worker_Loaded" OnWorkerUnloaded="On_Worker_Unloaded" />
        </dx:ContentControl>
    </ContentCollection>
</dx:TabPage>

There are 2 custom events on the user control

public event EventHandler WorkerLoaded;
public event EventHandler WorkerUnloaded;

I have the event handlers in the main aspx page

protected void On_Worker_Loaded(object sender, EventArgs e)
{
    btnNext.Enabled = true;
}

protected void On_Worker_Unloaded(object sender, EventArgs e)
{
    btnNext.Enabled = false;
}

The On_Worker_Loaded event fires without an issue. I can debug and watch the button become enabled. My problem is when the screen loads the button is still disabled. In my aspx page I disable the button:

<dx:ASPxButton ID="btnNext" runat="server" Text="Next" Theme="MetropolisBlue" 
                onclick="btnNext_Click" Enabled="false"></dx:ASPxButton>

The 'Next' button is already disabled. This is why you can't really see it. I have framed it with the black outline. When I click that OK button the WorkerLoaded Event fires.

The only other disable is on the On_Worker_Unloaded Event Handler. I don't have it hooked up yet. There is nothing else that causes the button to disable. Any Ideas what I'm missing?

Thanks!

UPDATE

The User Control has a UpdatePanel in it. I don't know if that makes a difference but I thought I would include that. Something else weird happened I noticed. After enabling the button I noticed that if I did a postback the button would be enabled. Does that ring any bells for anyone?

Answer 1

It seems the loaded event is being called before the Enabled=false property is set.

In your debugger check to see whether the Enabled property is already false when the event is called.

Also, what triggers the WorkerLoaded event?

Answer 2

In the end I found a solution that works for me. I put the Next button and the Previous buttons inside their own Update Panel. After I did this everything worked without issue. Thanks for all the ideas and help.