C# UserControl Bubbling events

  • Thread starter Thread starter Andy
  • Start date Start date
A

Andy

Alright, I am beyond confused here and need some guidance. I need a
C# only sample. I have a simple Page and within it i am creating a
user control (ascx). The user control contains textboxes, buttons,
ect. I would like to catch/add a handler/recieve the Button.OnClick
event from the buttons that are in the user control, in the Page.
How? As far as I can tell, my only route is to:

RaiseBubbleEvent in the Button.OnClick in the UserControl
Override the OnBubbleEvent in the UserControl
Override the OnBubbleEvent in the Page from the already Override(n)
UserControl

This is stupid. All I want a custom event, call it CustomEvent with
what ever signature I want, and I would like to allow the instance to
have the event CustomEvent override(n). Please help. I must be
missing the bus on this one...I can't seem to find a good C# sample
for what seems so common/trivial. TIA
 
I might well be missing something here but...

You can simplify what you do. The simplest is:
1) Call RaiseBubbleEvent in your Button.OnClick event handler in your
user control.
2) Override OnBubbleEvent in in the page.
The OnBubbleEvent handler may gets lots of events, so you need to
identify your event. You do this by either identifying the source of
the event or defining your own event args and passing them in the
RaiseBubbleEvent.

That is the minimum. I think good programming practice, especially if
third parties use the control, would be to provide a public delegate
as an event handler in the control. This requires:
1) Define MyEventArgs from System.EventArgs
2) Define a delgate event handler: MyEvent( object source, MyEventArgs
args)
3) Call RaiseBubbleEvent in the Button.OnClick
4) Override OnBubbleEvent in the control. This calls the delegate if
it is initialised.
5) Define a delegate function in Page and assign it to the delegate
event handler of the control.

Basically all you are doing in steps 1 to 4 is define your own event
handler for the control. This is done once in the control. Step 5 is
done on every page that uses the control - which is nicer than
overriding OnBubbleEvent in every page that uses the control.

I used the simple example in the on-line documentation for
RaiseBubbleEvent.

HTH
Charles
 
Andy wrote: said:
Alright, I am beyond confused here and need some guidance. I need a
C# only sample. I have a simple Page and within it i am creating a
user control (ascx). The user control contains textboxes, buttons,
ect. I would like to catch/add a handler/recieve the Button.OnClick
event from the buttons that are in the user control, in the Page.
How? As far as I can tell, my only route is to:
Click to expand...

Well, there's three choices.
1. Use BubbleEvent

2. Make the button public and let the owner page attach the event
directly

3. Define your own event that runs in response to Button.OnClick,
and have the page attach to that event (I suspect this is what you
really want here).
RaiseBubbleEvent in the Button.OnClick in the UserControl
Override the OnBubbleEvent in the UserControl
Override the OnBubbleEvent in the Page from the already Override(n)
UserControl

This is stupid. All I want a custom event, call it CustomEvent with
what ever signature I want, and I would like to allow the instance to
have the event CustomEvent override(n). Please help. I must be
missing the bus on this one...I can't seem to find a good C# sample
for what seems so common/trivial. TIA
Click to expand...

I'm not sure you actually have a real need for BubbleEvent here.
BubbleEvent is largely for those situation where there's a lot of
dynamic control creation going on. If all you want is a custom event,
why not just define one and use standard delegate/event stuff, and skip
the BubbleEvent stuff altogether? Am I missing something?

// inside the control

public event EventHandler MyEvent;

private void MyButton_OnClick(object sender, EventArgs e)
{
if(MyEvent != null)
MyEvent(this, e); // or whatever args you want
}

// and inside the Page object

private void Page_Load(...)
{
MyUserControl.MyEvent += new EventHandler(myHandler);
}


I hope this helps, though I feel as if I'm actually missing something
here.
 
Think my brain was miss firing yesterday from reading the mounds of
crap on bubbling ect...anyways, went the route you described which was
exactly what I was looking to do. Was mostly confused on how the
custom events related back to intrinsic events for the the internal
user controls (read as, exposing internal control events).
 
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