Does assigning null remove all event handlers from an object?
yes, you should use overloaded -= to unsubscribe an event. simply assigning a reference to null will not do that automatically. The object will still be listening to that event.
delegates
Recursive call – Action lambda
Just define the delegate Action and assign null to it before calling it recursively. Action<IItem, Int32> recurse = null; Then recurse = new Action<IItem, Int32>((item, depth ) => { if (item.Items.Count() > 0) recurse(item, depth + 1); // red squiggly here // … }); Good luck!
Co- and Contravariance bugs in .NET 4.0
Long story short: delegate combining is all messed up with respect to variance. We discovered this late in the cycle. We’re working with the CLR team to see if we can come up with some way to make all the common scenarios work without breaking backwards compatibility, and so on, but whatever we come up … Read more
Automatically delegating all methods of a java class
Perhaps the dynamic Proxy of java can help you. It only works if you consequently use interfaces. In this case, I will call the interface MyInterface and set up a default implementation: public class MyClass implements MyInterface { @Override public void method1() { System.out.println(“foo1”); } @Override public void method2() { System.out.println(“foo2”); } @Override public void … Read more
Several UIAlertViews for a delegate
Tag the UIAlertViews like this: #define kAlertViewOne 1 #define kAlertViewTwo 2 UIAlertView *alertView1 = [[UIAlertView alloc] init… alertView1.tag = kAlertViewOne; UIAlertView *alertView2 = [[UIAlertView alloc] init… alertView2.tag = kAlertViewTwo; and then differentiate between them in the delegate methods using these tags: – (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex { if(alertView.tag == kAlertViewOne) { // … } else if(alertView.tag … Read more
Does jQuery have a handleout for .delegate(‘hover’)?
User113716’s great answer will no longer work in jQuery 1.9+, because the pseudo-event hover is no longer supported (upgrade guide). Also since jQuery 3.0 delegate() for binding events is officially deprecated, so please use the new on()(docs) for all event binding purposes. You can easily migrate user113716‘s solution by replacing hover with mouseenter mouseleave and … Read more
How do I Unregister ‘anonymous’ event handler [duplicate]
Give your instance of the anonymous delegate a name: EventHandler<NewEventArg> handler = delegate(object sender, NewEventArgs e) { //some code }; Subject.NewEvent += handler; Subject.NewEvent -= handler;
Why are delegates reference types?
The question boils down to this: the CLI (Common Language Infrastructure) specification says that delegates are reference types. Why is this so? One reason is clearly visible in the .NET Framework today. In the original design, there were two kinds of delegates: normal delegates and “multicast” delegates, which could have more than one target in … Read more
Removing event handlers
It is the same. The second is merely syntactic sugar for the first, and equality comparison is overloaded appropriately for delegate types: Two delegates of the same type with the same targets, methods, and invocation lists are considered equal. Source: MSDN, Delegate.Equality Operator
Setting delegate for UIImagePicker returns error
You forgot about UINavigationControllerDelegate in your ViewController class defenition. The image picker’s delegate object. Declaration unowned(unsafe) var delegate: protocol<UIImagePickerControllerDelegate, UINavigationControllerDelegate>?