ASP.NET - Add Event Handler to LinkButton inside of Repeater in a RenderContent call

Question

I've got a Sharepoint WebPart which loads a custom User Control. The user control contains a Repeater which in turn contains several LinkButtons.

In the RenderContent call in the Webpart I've got some code to add event handlers:

        ArrayList nextPages = new ArrayList();
        //populate nextPages ....
        AfterPageRepeater.DataSource = nextPages;
        AfterPageRepeater.DataBind();

        foreach (Control oRepeaterControl in AfterPageRepeater.Controls)
        {
            if (oRepeaterControl is RepeaterItem)
            {
                if (oRepeaterControl.HasControls())
                {
                    foreach (Control oControl in oRepeaterControl.Controls)
                    {
                        if (oControl is LinkButton)
                        {
                            ((LinkButton)oControl).Click += new EventHandler(PageNavigateButton_Click);
                        }
                    }
                }
            }
        }

The function PageNavigateButton_Click is never called however. I can see it being added as an event handler in the debugger however.

Any ideas? I'm stumped how to do this.

I've messed around with the code a bit after reading people's suggestions. I'm trying to add the event handlers now in the CreateChildControls() function but they still aren't being fired. Thanks for all of the help so far, it's appreciated — Gordon Thompson, Sep 24 '08 at 15:49
For those seeing this late in the game. Don't use CreateChildControls... That's still too late in the cycle. Instead override the OnInit handler to build all your dynamic controls. — NotMe, Sep 03 '09 at 01:51

Mark Cidade · Accepted Answer · 2008-09-23T18:50:44.913

By the time RenderContent() is called, all the registered event handlers have been called by the framework. You need to add the event handlers in an earlier method, like OnLoad():

protected override void OnLoad(EventArge e)
 { base.OnLoad(e);
   EnsureChildControls();

   var linkButtons = from c in AfterPageRepeater.Controls
                                                .OfType<RepeaterItem>()
                     where c.HasControls()
                     select c into ris
                        from lb in ris.OfType<LinkButton>()
                        select lb;

   foreach(var linkButton in linkButtons)
    { linkButton.Click += PageNavigateButton_Click
    }                          
 }

I've tried putting the code which adds the event handlers in the CreateChildControls() method to now avail. Thanks — Gordon Thompson, Sep 24 '08 at 15:46

score 2 · Answer 2 · answered Sep 23 '08 at 18:32

Have you tried assigning the CommandName and CommandArgument properties to each button as you iterate through? The Repeater control supports the ItemCommand event, which is an event that will be raised when a control with the CommandName property is hit.

From there it is easy enough to process because the CommandName and CommandArgument values are passed into the event and are readily accessible.

score 1 · Answer 3 · answered Sep 23 '08 at 18:29

1

You need to make sure that the link button is re-added to the control tree and/or that the event is rewired up to the control before the event fires.

Article @ 4guysfromrolla

answered Sep 23 '08 at 18:29

Darren Kopp

76,581
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Matt Blaine · Answer 4 · 2008-09-23T18:46:33.787

I've never done a SharePoint WebPart, so I don't know if this will apply. But if it were a plain-old apsx page, I'd say that by the time it's rendering, it's too late. Try adding the event handlers in the control's Init or PreInit events.

Edit: Wait, I think Dilli-O might be right. See the Adding Button Controls to a Repeater section at the end of http://www.ondotnet.com/pub/a/dotnet/2003/03/03/repeater.html. It's in VB.NET, but you can easily do the same thing in C#.

score 1 · Answer 5 · answered Sep 23 '08 at 22:38

1

As others have pointed out, you're adding the event handler too late in the page life cycle. For SharePoint WebParts you'd typically want to override the class' OnInit/CreateChildControls methods to handle the activity.

answered Sep 23 '08 at 22:38

Preston Guillot

6,493
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score 1 · Answer 6 · answered Aug 26 '09 at 15:35

1

YOu need your webpart to implement the INamingContainer marker interface, it is used by the framework to allow postbacks to return to the correct control... Also the controls in your webpart all need to have an ID.

answered Aug 26 '09 at 15:35

Colin

10,630
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ASP.NET - Add Event Handler to LinkButton inside of Repeater in a RenderContent call

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