Event handlers called twice, or not at all

Discussion in 'ASP .Net Web Controls' started by Andy Baldwin, Oct 14, 2004.

  1. Andy Baldwin

    Andy Baldwin Guest

    Ok, sorry for the long post in advance, but I need an expert opinion
    here. I have already crawled through the groups via google and
    additionally asked everyone that I can find in Yahoo's chat for
    programmers and web designers.

    Here is the issue in a nutshell, I am having a situation where my
    event handlers are firing twice, or not at all. We need some
    background here, because I am going about things very different from
    traditional ASP.Net development. Most of the tutorials, articles and
    books that I have read have rarely gone over how to programatically
    create your own web controls, much less to the extent that I am doing
    it. I am basically making a way that all of my (custom composite) web
    controls are created for me dynamically based off of info gathered
    from SQL Server and some of my own tables that contain metadata about
    the DB in question. This being said, I have a "Form" object that
    implements placeholder. When you construct this object (in the
    simplest way), you pass in a table name and an optional record ID.
    With this information I gladly create a form, including dropdowns for
    secondary table lookups and calendar controls (that default to
    hidden). Lets take the calendar control for an example. My composite
    calendar control has 3 controls in all actuality. A text box that
    allows the user to type in a date, a button to hide and show the
    calendar control, and the calendar control itself. There are two
    events associated with this control, the onclick event for the button
    hides and shows the associated calendar, and the dateChange event (I
    think thats what it is called) puts the selected date into the
    textbox. Now that we know this, let me tell you since the eventhandler
    for hide/show is called two times, it is never shown (It shows it,
    then hides it in a split second). IF I say "if its not a postback,
    show the form", then the event is never fired, because on postback,
    the button, much less than it's event do not exist. In essence, when I
    click the button, it first fires the page_load event, then either:

    1) If I always generate the form, calls the button click event two
    2) If I only generate the form on a non postback, then never fires the
    event because the button was never re-generated in the postback.

    After saying this, I realize that somehow the events are not being
    persisted as needing to be executed regardless of if the original
    button even exists or not, Is this indeed the case?

    There is hope yet. I have an older version of the code that did work
    correctly, but I have done some major refactoring, combining
    appropriate code into the appropriate class files (got rid of a few
    files that way, and it makes a lot more sense now). You can find a
    diagram of how it used to be and how it is now here:


    Hopefully this will jog someones memory

    So, so far I have tried these things:

    1) Flip flopped the AutoEventWireUp field in the page directives.
    2) Set "EnableViewState" on the placeholder that contains the form to
    true (although I read that this defaults to true anyways).
    3) Stepped through my code a hundred times, I am only adding the event
    handler once, and I even remove the same event handler before I add it
    again. If it was a case of the event handlers being re-added over and
    over again to the same control, I would have to assume that every time
    I click the button it would add one to the number of times that the
    event fires, but not only is that not the case.
    4) There is nothing in the stack trace between calls to the event
    handlers, so the CLR MUST be calling it two times, and I am not
    accidentally calling the handler explicitly
    5) Did Global searches for the calendar class and other similar
    variables, the ones that are used are all correct.
    6) Looked at quite a few other associated events and they have the
    same problem.

    I realize my next steps are:

    1) Slowly roll back the code to it's previous version to figure out
    the deal (this would take a day or two, then I would have to add all
    that stuff in again.
    2) Look for a hack that works (although I thought that remkoving the
    event handler before adding it again, was a hack.
    3) Reinstall the .Net framework and hope this is a fluke (although I
    am pretty sure I have the latest version.

    But I am hoping that someone here can help out.

    Again this worked with an older, version of the code, but no more.

    PLEASE Help!

    Andy Baldwin, Oct 14, 2004
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  2. Andy Baldwin

    vbMental Guest

    First let me say I feel your pain. I am struggling with a similar situation.
    Maybe we can help each other. I think it lies in understanding the order of
    events and interaction of the page and controls.
    Right now I'm have usercontrols inside of user controls and the events get
    out of wack also.

    I got kind of lost in your detail though, let me if you have figured it out
    vbMental, Oct 29, 2004
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