Had the same 27% problem with an emulator. It only got fixed after I deleted the AVD and recreated it, so this is very likely device/emulator related (and furthermore restarting the ADB did not fix the problem). EDIT: Found this over at project pages as Issue #21073, answered by benpar: Update: This scenario can also … Read more
I’m assuming you would normally do something like this as part of a factory implementation, where the actual types aren’t known at compile-time… First, note that an easier approach may be a post-create init step, then you can use generics: static T Create<T>({args}) where T : class, ISomeInitInterface, new() { T t = new T(); … Read more
Both are equally correct, but the documentation for Control.Invoke states that: The delegate can be an instance of EventHandler, in which case the sender parameter will contain this control, and the event parameter will contain EventArgs.Empty. The delegate can also be an instance of MethodInvoker, or any other delegate that takes a void parameter list. … Read more
Yes, delegates are in many ways like single-method interfaces. However: There is support built into the CLR for them There’s support in the framework for them, including multi-cast abilities and asynchronous invocation There’s additional C#/VB language support in the form of method group conversions, lambda expressions, anonymous methods They’re mandated for events (i.e. events and … Read more
The C# compiler’s default implementation of adding an event handler calls Delegate.Combine, while removing an event handler calls Delegate.Remove: Fire = (MyDelegate) Delegate.Remove(Fire, new MyDelegate(Program.OnFire)); The Framework’s implementation of Delegate.Remove doesn’t look at the MyDelegate object itself, but at the method the delegate refers to (Program.OnFire). Thus, it’s perfectly safe to create a new MyDelegate … Read more
A delegate is a pointer to an object with a set of methods the delegate-holder knows how to call. In other words, it’s a mechanism to enable specific callbacks from a later-created object. A good example is UIAlertView. You create a UIAlertView object to show a short message box to users, possibly giving them a … Read more
In TypeScript, interfaces can have call signatures. In your example, you could declare it like this: interface Greeter { (message: string): void; } function sayHi(greeter: Greeter) { greeter(‘Hello!’); } sayHi((msg) => console.log(msg)); // msg is inferred as string
The rule of thumb here is how many clients would like to be notified of an event. If it’s mainly one object (e.g. to dismiss a view or to act upon a button clicked, or to react to a failed download) then you should use the delegate model. If the event you emit may be … Read more
It cannot be done by Func but you can define a custom delegate for it: public delegate object MethodNameDelegate(ref float y); Usage example: public object MethodWithRefFloat(ref float y) { return null; } public void MethodCallThroughDelegate() { MethodNameDelegate myDelegate = MethodWithRefFloat; float y = 0; myDelegate(ref y); }
Update: An article with the complete source code and a more detailed discussion has been posted on The Code Project. Well, the problem with pointers to methods is that they’re not all the same size. So instead of storing pointers to methods directly, we need to “standardize” them so that they are of a constant … Read more