delegates

问题 The Run2 method is run. But the Run method is not run. What is the reason ? The only difference between two methods is because parameter. public class MyClass { public string Name { get; set; } } [TestFixture] public class Test { public IEnumerable<T> TestMethod<T>(int i) { //do something return null; } public IEnumerable<T> TestMethod2<T>() { //do something return null; } [Test] public void Run() { MethodInfo mi = this.GetType().GetMethod("TestMethod").MakeGenericMethod(typeof(MyClass)); var

问题 What advantage is there to implementing the four delegate methods: (void)controllerWillChangeContent:(NSFetchedResultsController *)controller (void)controller:(NSFetchedResultsController *)controller didChangeSection:(id )sectionInfo atIndex:(NSUInteger)sectionIndex forChangeType:(NSFetchedResultsChangeType)type (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type newIndexPath

问题 I use delegates with lambda expressions instead of methods with just one line of code like: Func<int, int, int> Add = (x, y) => x + y; int Result = Add(1, 2); // 3 Now I have the problem that I need a unknown number of parameters. Is there a was to solve it like this: Func<string, params string[], string> MergeFormat = (Look, values) => string.Format(Look, string.Join("-", values)); with params string[] the result would be string.Format(func, string.Join("-", v1, v2, v3)); //currently

问题 (Using .NET 4.0) Ok, so I have private Dictionary<int, Action<IMyInterface, IMyInterface>> handler {get; set;} public void Foo<T, U>(Action<T, U> myAction) where T : IMyInterface where U : IMyInterface { // | This line Fails // V Action<IMyInterface, IMyInterface> anotherAction = myAction; handler.Add(someInt, anotherAction); } I'm trying to store the delegate in a generic collection, so I can pull it back out later to invoke it. How do I properly cast it? 回答1: The generic parameters to the

问题 I'm using Twitter Bootstrap 2.3.2 and I'm registering a popover to open whenever a td with a selector is hovered over. However I have noticed within the console that the content callback is being trigger twice. Is there a way to prevent this from happening? $('#table-data').popover({ selector: '.td-popover', trigger : 'hover', content : function () { console.log(this, arguments) return 'hello'; } }); <table id="table-data"> <tbody> <tr> <td></td> <td class="td-popover"></td> <td></td> <td

问题 I have an external application that provides an event StkQuit . I subscribe to this event in a static class that handles all communication between my application and [the] external application. I would like to subscribe to the StkQuit event using another handler that sits on my form class. This handler will inform the user that the external application has been closed. I would like to have a generic method in the static class called SubscribeToStkQuit that accepts a delegate as a parameter

问题 I encountered a problem when using a generic class in swift as a delegate. for example i tried to use a generic NSFetchedResultsDelegate defined as: class FetchedTableController<T:NSManagedObject> : NSFetchedResultsControllerDelegate Inside the class i setup a NSFetchedResultsController and set the delegate to 'self'. But for some reason the delegate methods never got called. When i removed the Generic part of the class, the delegates got called as expected: class FetchedTableController :

问题 I have a list of methods that do pretty much the same thing, except a few differences: void DoWork(string parameter1, string parameter2) { //Common code ... //Custom code ... //Common code ... } I want to streamline the solution with reusing the common code by passing custom code from another method. I assume I have to use an action with parameters to accomplish this, but can't figure out how. 回答1: The other answers are great, but you may need to return something from the custom code, so you

问题 My class name is HandMotionRecognition and I'm calling getColorPixel method in mouse callback. This is in OpenCV using Visual Studio 2010 and project type is c++ -> cli. The standard code (unless I'm mistaken) to handle mouse events is cvSetMouseCallback( "CameraIn", getColorPixel, (void*) frameHSV); But when I compile it gives a compile time error error C3867: 'HandMotionRecognition::getColorPixel': function call missing argument list; use '&HandMotionRecognition::getColorPixel' to create a

问题 I notice that QML has some unspecified problem with the following - when a delegate tries to instantiate an object that contains it (the delegate that is). Consider this trivial tree builder example: // Object.qml Row { property int c : 0 Rectangle { width: 50 height: 50 color: "red" border.color: "black" MouseArea { anchors.fill: parent acceptedButtons: Qt.LeftButton | Qt.RightButton onClicked: { if (mouse.button === Qt.LeftButton) c++ else if (c) c-- } } } List { model: c } } // List.qml