How to use the this (or something of that kind) referring to the delegate instance instead of the class instance ?
instance.OnEventFoo += delegate()
{
if (condition)
{
instance.OnEventBar += this;
}
};
Asked
Active
Viewed 99 times
3
56ka
- 1,463
- 1
- 21
- 37
-
Does the `RowChanged` event pass inn `sender, e`? – Lasse V. Karlsen Dec 16 '13 at 09:36
-
1http://stackoverflow.com/questions/183367/unsubscribe-anonymous-method-in-c-sharp – Vadim Dec 16 '13 at 09:36
-
@LasseV.Karlsen yes but it does not matter for the example :) – 56ka Dec 16 '13 at 09:38
-
@Vladim Thx but the question is "how to refer to this" and not "how to remove a delegate" – 56ka Dec 16 '13 at 09:39
-
No, I misread your question, so never mind me. – Lasse V. Karlsen Dec 16 '13 at 09:42
2 Answers
4
Since you can't refer to a variable before it is declared, you have to:
- first declare the variable,
- then assign a delegate,
- then register the handler with the event.
// Add an anonymous delegate to the events list and auto-removes automatically if item disposed
DataRowChangeEventHandler handler = null;
handler = (sender, args) =>
{
if (condition)
{
// need to remove this delegate instance of the events list
RowChanged -= handler;
}
};
something.RowChanged += handler;
dcastro
- 66,540
- 21
- 145
- 155
3
You need to store it in a variable somewhere. For example:
EventHandler rowChanged = null; // to avoid "uninitialized variable" error
rowChanged = (s, e) =>
{
if (condition)
{
// this will unsubscribe from the event as expected
RowChanged -= rowChanged;
}
};
Jon
- 428,835
- 81
- 738
- 806
-
-
@56ka No. You need a delegate that references itself. And since you can't refer to a variable before it is declared, you need to declare it first. – dcastro Dec 16 '13 at 09:43
-
-