Asp – Custom Control Event Not Firing First Time

asp.net

My application runs from a single page (default.aspx) and loads custom controls based on what the user selects (this is done in the LoadPage event).

The problem is that the FIRST time some new controls are loaded onto the page and a button is clicked, the page is NOT firing the Click event. This also happens when using a GridView and other controls.

However, if I simply reload the page a second time, the events are fired properly. (this works successfully every time)

Two questions:
1) Why would this occur?
2) How can I troubleshoot it better? I've tried checking the Request.Form(__EVENTTARGET) (which is blank)

There are times when it works properly which suggests a PostBack issue – but it's not obvious.

Best Answer

I have identified the source of the problem and wanted to note it here so that it may help others.

The code in question had three different methods that assigned the Custom controls ID property. Two of those methods were doing it dynamically so the first time in, the custom control's ID was "UserProfile" - the second time (during the post-back), it became "uc1" (user Control 1). As a result, since the two IDs were not the same, ASP.Net did not recognize them as being the same control.

The SECOND time it posted back, it used the second method and thus the controls were the same and did get updated.

Related Solutions

C# – How todentify Postback event in Page_Load

This should get you the control that caused the postback:

public static Control GetPostBackControl(Page page)
{
    Control control = null;

    string ctrlname = page.Request.Params.Get("__EVENTTARGET");
    if (ctrlname != null && ctrlname != string.Empty)
    {
        control = page.FindControl(ctrlname);
    }
    else
    {
        foreach (string ctl in page.Request.Form)
        {
            Control c = page.FindControl(ctl);
            if (c is System.Web.UI.WebControls.Button)
            {
                control = c;
                break;
            }
        }
    }
    return control;
}

Read more about this on this page: http://ryanfarley.com/blog/archive/2005/03/11/1886.aspx

ASP.NET – Control Events Not Firing Inside Repeater

Your edited code has residual CommandArgument and CommandName properties; are you actually handling the Repeater.ItemCommand event?

If so, and if your page calls the control's Fill method on postbacks, that would explain it.

This classic ASP.NET hair-tearing problem is explained in these posts: A Stumper of an ASP.NET Question and A Stumper of an ASP.NET Question: SOLVED!

The explanation is a little mind-bending, but the crux of it is that Repeater.DataBind interferes with ASP.NET's ability to determine which repeater button caused a postback.

Best Answer

Related Solutions

C# – How todentify Postback event in Page_Load

ASP.NET – Control Events Not Firing Inside Repeater

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