CODEWITHSUNDEEP
asp.netuser-controlsevent-handling
Reuben
Reuben

Reputation: 4276

Propagation of events to User Controls in ASP.NET

I have a user control (Navigation) nested within another user control (Header) that is dynamically loaded from a Control class (Standard).

The user controls, Navigation and Header have AutoEventWireup = false.

The control class Standard calls loads the Header user control from a configuration item.

private void layoutAndRender(HtmlTextWriter output, string UserControlKey, NameValueCollection UserControlsConfiguration)
{
    if(UserControlsConfiguration[UserControlKey] != null && UserControlsConfiguration[UserControlKey].ToString() != "")
    {
        string suc = System.Web.HttpContext.Current.Request.ApplicationPath + UserControlsConfiguration[UserControlKey].ToString();
        UserControl ucToRender = (UserControl)this.Page.LoadControl(suc);
        ucToRender.RenderControl(output);
    }
}

My problem is that I want to initialize an object in the Navigation user control that can accept Page.Request and Page.Response, but events don't seem to be firing in the Navigation code behind.

The code I'm using to initialize my object is:

this.browser = new Browser(this.Request, this.Response);

I tried doing this during the Navigation constructor but this.Request and this.Response are not set at that time.

I tried using the statement in a void Page_Load(object sender, System.EventArgs e) method, but this doesn't seem to be firing, even if I have this.Load += new System.EventHandler(this.Page_Load); in the Navigation constructor.

I've also tried similar statements for Page_Init and Page_PreRender, but none of these seem to be firing.

Is it that a control loaded with LoadControl does not fire Load or Init events, if loaded the way I have loaded them, and the same goes for any user controls that it may include?

Upvotes: 1

Views: 342

Answers (2)

Reuben
Reuben

Reputation: 4276

Unfortunately, this is legacy code, and not always done the right way.

In particularly, because the user control is loaded and rendered manually, it probably skips most of the event model that I wanted to take advantage of. Ideally, it should have done an AddControl() to the page, rather than rendering the control to a HtmlTextWriter.

My work around is to override the RenderControl method, and initialize the browser property before passing RenderControl up the chain.

Upvotes: 0

rsbarro
rsbarro

Reputation: 27349

If AutoEventWireup is set to false for the controls that you want to load, then you should override the OnInit method to wire up the Load event handler for the controls. The Request and Response properties should be available from within Page_Load.

For example:

public class Header : Control
{
    private void Page_Load(object sender, EventArgs e)
    {
    }

    override protected void OnInit(EventArgs e)
    {
        this.Load += new System.EventHandler(this.Page_Load);
    }   
}

See MSDN for more info on AutoEventWireup: http://support.microsoft.com/kb/324151

Upvotes: 1

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