Do you *really* want to have to attach an event handler for every single
node in a TreeView? That sounds like a massive overhead compared to one
event handler...
When I do have one object that corresponds to each node in something like a
tree view or an XML document, I just maintain a hashtable. So to give an
example where I agree with you - with the Toolbar control, I think it's
wrong that the Toolbar raises events not buttons. It's not a big deal - my
event handler just looks something like this:
private void toolBar_ButtonClick(object sender,
ToolBarButtonClickEventArgs e) {
MyObject obj = (MyObject) toolBarButtonToObject[e.Button];
if (obj != null) obj.OnClick();
}
Looking an item up in a hashtable is not exactly a massive overhead. And
this requires you to hook the event just *once*. You seem to be proposing
that every object would be attached to the event handler. That would indeed
be a massive overhead as you say. It would also be a mad thing to do. If
all the events are raised through a single object, why would you hook that
event handler more than once? Just have a single handler that locates the
object that you want to deal with the event, like the one above.
For things like the TreeView I think that the way Microsoft has done it is
better than what you are proposing for most cases - the majority of tree
view click handling code I've written has used the same code for most of the
nodes, so I wouldn't really want a seperate event handler for each node.
--
Ian Griffiths
DevelopMentor
----- Original Message -----
From: "Christian Schmitz" <[EMAIL PROTECTED]>
> I have a problem with the location of events in the .NET framework. Why
> Microsoft locates the events in top level classes and not in the classes
> where the events really happens? For instance: TreeView raises events, not
> the TreeNode or XMLDocument raises events not the XMLNode! I think, it is
a
> bad concept to do it in this style.
> For example: If you have a large object model which holds it's data in an
> XMLDocument and every object is linked in a 1:1 relationship to a XMLNode-
> object how can I realize that the object "hears" what happens in its
> XMLNode? When I use the .NET style I would link every object to the
> XMLDocument and filter the suitable events. That means a tremendous
> overhead.
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