Re: [ENTER] key causing major headaches.

From: Mythran (kip_potter_at_hotmail.com)
Date: 06/25/04 

Date: Fri, 25 Jun 2004 15:27:14 -0700

IN-LINE COMMENTS:

"Eric" <ejproductions-msnews7831@mailblocks.com> wrote in message
news:%23vBybPuWEHA.3140@TK2MSFTNGP10.phx.gbl...
> Well Everyone,
>
> I believe I've stumbled upon an acceptable solution. For the
> curious-minded...
>
That's Me! 0>8-{P

> An obvious solution would be to disable the [ENTER] button entirely. Doing
> this with javascript however, is a problem becaue if the client has
> javascript disabled or doesn't support it you will still get the same "ghost
> postbacks" where the source (clicked button) is unknown.
>
The source (clicked button) is unknown for a very good reason. There is no
button clicked :) It is the default for HTML forms. It does an automatic submit
of the form w/o any buttons being clicked.

> My solution is to do this with an image instead of a button. To do this,
> create a <asp:LinkButton> object and set its Text property to be the HTML
> for an <img>. You can then use the Click event of the LinkButton object. I
> didn't think this would work for quite a while (because when I tested it, it
> didn't work). As it turns out, the reason my tests resulted in failure is
> because of bug in Internet Explorer...
>

<script language="JavaScript">
    function Element_OnKeyPress(e)
    {
        if (!e) {
            e = window.event;

            if (!e) {
                alert('Could not get the event object!');
            }
        }

        var srcElement = e.srcElement;
        // Code to detect which button to simulate clicking.

    }
</script>

In the elements that are problematic, add the onkeypress event (Example:

<input type="text" onkeypress="JavaScript:Element_OnKeyPress(event);">

May want to double check e.srcElement. Can't remember if other browsers support
it or not...

> It turns out that if you have a <form> with less than two text boxes IE
> automatically submits the form when the [ENTER] key is pressed. This
> happens WHETHER OR NOT you have a submit button in the <form>. If you have
> 2 OR MORE text boxes, IE will NOT automatically submit the form when [ENTER]
> is pressed. Instead, it will CLICK the first button it encounters following
> the widget with the focus. This latter behavior is what *should* occur
> regardless of the number of text boxes. So... to use my <asp:LinkButton>
> solution, you ALSO have to have at least 2 text boxes in the <form>. If
> your application only calls for one (or zero), you must supplement the
> "missing" text box(es) with hidden text box(es). This could be accomplished
> by using CSS to set the visibility to hidden, the width to 0, or both.
>
Hrm, yer right...and I knew this but it didn't come to my mind earlier.

> Jumping through these hoops will give you the expected behavior. My next
> step will be to derive my own "ImageButton" control (from asp:LinkButton)
> that includes the hidden text boxes. It may also accept an alternate
> MouseoverImage property to emulate the appearance of an actual button (using
> *optional* client-side javascript).
>

> If some jaded soul out there winds up as stuck as I was, I hope this
> solution finds them!
>
>
> Regards,
>
> Eric
>

Regards,

Mythran

>
> "Eric" <ejproductions-msnews7831@mailblocks.com> wrote in message
> news:exRi9atWEHA.3716@TK2MSFTNGP11.phx.gbl...
> > Hi All,
> >
> > I'm very experienced in traditional ASP and am new to (am learning)
> ASP.NET.
> > FYI: I am initially learning ASP.NET with VB.NET to ease the transition
> for
> > me. I have encountered what I believe to be a huge limitation with
> ASP.NET
> > and I'm wondering how you have handeled this problem.
> >
> > Let's suppose you have a page where the user can do one of two things: add
> a
> > "Category", or add a "Movie Title" to an already existing category. This
> is
> > just a make-believe scenario that I'm using to make a point: You have two
> > distinct sections to your page... one section contains a text box and a
> > button (for adding a new category) and another section contains a dropdown
> > menu of categories, a text box, and a different button (for adding a new
> > movie title).
> >
> > You can have have the Click event of the first button ("bAddCategory")
> > handle the addition of the new category, and you can have the Click event
> of
> > the second button ("bAddMovie") add the new movie title. So far, so good.
> >
> > My problem is this: what if the user presses the [ENTER] key on his/her
> > keyboard? Doing this does not fire either Click event. I can (in
> essence)
> > make a "default" button by adding the following to the server-side Load
> > event for the page:
> >
> > Page.RegisterHiddenField("__EVENTTARGET", bAddMovie.ClientID)
> >
> > Doing this will cause the Click event for bAddMovie to fire when the user
> > presses [ENTER]. However... I don't want bAddMovie to be the default
> button
> > if the user is in the process of typing a new category name (in that case,
> I
> > obviously would want bAddCategory to be the default).
> >
> > In traditional ASP, I would simply have two <form>s on the page. One
> <form>
> > would encapsulate the widgets for entering a category and a second <form>
> > would encapsulate the widgets for entering a movie. Each of the two
> <form>
> > tags would contain a <input type="hidden"> element containing a name/value
> > pair indicating which form was submitted on postback.
> >
> > In ASP.NET, I see no way to emulate this concept. ASP.NET does not let me
> > have two form tags (with runat="server" defined). And, if I use a
> > client-side (traditional) <form>, I cannot use any of the ASP.NET web
> > controls (like <asp:DropDownList>, etc.). Not being able to use these web
> > controls, to me, defeats the whole purpose of using ASP.NET. If I revert
> > back to a traditional <form> tag, I don't get events, viewstates, or any
> > other fancy ASP.NET features.
> >
> > This concept (of having two forms) is extremely important to me. What do
> I
> > do!? Any and all help is very much appreciated!!
> >
> >
> > Regards,
> >
> > Eric
> >
> >
>
>