objective c delegate

Event is an important concept in Windows-based programming. In almost all Windows applications, a large number of asynchronous calls are involved, such as responding to and Clicking buttons and processing Windows system messages. These asynchronous calls must be completed through events. It is no exception even on the next-generation development platform --. NET.So what is an event? An event is a message sent from an object. The message indicates a specific action or a specific condition. For ex

Beginner's note (C # Delegate ), 1. Delegation Overview In short, the delegate is to pass the method as a parameter. A delegate is a type of dynamic calling method. It is referenced in the same way as classes, interfaces, and arrays. In C #, you can declare the delegate type, create a

that allows other objects to receive such an event. This is a very common and must-do task for an object, because without communication, controllers will not be integrated into the entire application. Another purpose of the controller is to self-contain as much as possible.We want controllers to exist in its own way and not to be coupled with other controllers on controllers. Controllers can create other controllers and they can communicate freely between them, but we do not want the controller

Original Definition:Delegation is a typeSaves the method reference type in the object, and is also a type-safe function pointer.One way to understand DelegationYou can specify a name for the method signature as the role of the delegate.DelegatedThe definition is similar to the definition of a method, but there is no method body. The key word delegate must be added before the defined delegate name.. Because

Block usage and comparison (forwarding) between block and delegate, blockdelegate I have read an article about putting block and delegate together to make it easier for everyone to understand. I recommend it to you. The proxy design pattern is certainly very familiar to iOS developers. The proxy delegate is to delegate

in. in. net, delegation, anonymous methods, and lambda expressions are three confusing concepts. the following Code can be seen: Which of the following code will be compiled in the first call? Which ones will return the expected answers? (Customer with ID 5 ). in fact, the answer is: all the six methods will not be compiled, and they can all return normal customers, which are functionally the same. if you are still asking yourself: Why? This Article will answer you. class customer { Publ

We all know that C # has the concept of "interface". The so-called "interface" is to define a set of standards and then implement the methods in the implementation class. Therefore, "interface, is the abstraction of a group of classes ". In the same way, we can regard "delegate" as "method abstraction", that is, to define a method template. As for how this method is specific, it is implemented by the method itself. We know that the biggest benefit

Delegation and events are widely used in. NET Framework. However, it is not easy for many people who have been in contact with C # for a long time to better understand delegation and events. They are like a hacker. People who have passed the hacker think it is too easy, and people who have never seen the delegate and event will feel different (BI) panic and uncomfortable. In this article, I will use two examples to describe what is delegation, why to

Suppose we have a generic object list Description: predicate Delegate The first thing you may think of is delegate implementation. The implementation method is as follows: // Method 1 Static Void Method1 () { // Create a list List Int > List = New List Int > (); List. addrange ( New Int [] { 1 , 2 , 3 , 4 , 5 , 6 }); // define a

Code Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->1. Definition of delegation: Delegation is the encapsulation of functions. It represents a "class" function. They all comply with certain signatures: they have the same parameter list and return value type. at the same time, the delegate can also be seen as an abstraction of the function, which is a "class" of the function ". in this case, the deleg

Delegate: In msdn, the first sentence about delegation is to associate the delegation with explicit or anonymous methods to instantiate the delegation. C ++ has a very powerful stuff-pointer. Of course, this is also a lot of criticism. C # has no pointer, but many times we need the powerful functions of C ++, but we cannot introduce memory defects in c ++, therefore, a delegate is displayed in C. "DelegateA

C # One of the delegate usage Chang jianzhao A while ago I discussed how to call another winform method in a winform. The best way to do this is to use delegate. Some friends also mentioned in the reply, google has sent a message, so I am sorry for the last time I used it. But fortunately, I still learned the knowledge. It may be a joke for others, but for myself, is a kind of progress. Haha, I don't want

1. What is a delegateIn terms of data structures, delegates are the same type of user-defined types as classes.A delegate is an abstraction of a method that stores the address of a series of methods that have the same signature and return type. When the delegate is invoked, all the methods contained by the delegate are executed.2, the definition of the delegation

// When I first listen to the delegate, I understand it as: one person entrusts another person to do something.// According to this idea, the following test program is designed// Leaders entrust their subordinates to do something. Using System;Using System. Collections. Generic;Using System. Text;Using System. Reflection; Namespace ConsoleApplication1{Public class FirstTest{Public static void test (){Lead Zhu Ge = new lead (); Zhu Ge. Issue the task (

A delegate is a type that stores the reference as a function. The delegate declaration is a very type function, but it does not contain a function body and uses delegate. The delegate Declaration refers A function signature is set, which contains a list of return types and parameters. After the

1. What is commissioned by the 1.1 Official explanation A delegate is a type that defines the method signature. When instantiating a delegate, You can associate its instance with any method with a compatible signature. You can call a method by entrusting an instance. 1.2 understanding A delegate is a class that executes methods (functions. An event is a speci

Document directory I. Introduction Ii. Delegate Concept Iii. event handling in C # Iv. Summary I. Introduction Event is an important concept in Windows-based programming. In almost all Windows applications, a large number of asynchronous calls are involved, such as responding to and Clicking buttons and processing Windows system messages. These asynchronous calls must be completed through events. It is no exception even on the next-generation de

Exception {Unable to convert anonymous method to type ' System.Delegate ' because it is not a delegate type} The delegate actually takes the method name as a parameter, but if there are many methods, it is necessary to indicate which parameter See the following code:This. Invoke (delegate{MessageBox.Show ("T4");});Developers familiar with WinForm know that this i

From:http://www.cnblogs.com/akwwl/p/3232679.html A delegate is a class that defines the type of the method so that the method can be passed as a parameter to another method. An event is a special kind of delegate. 1. Declaration of Delegation (1). Delegate Delegate the kind of statement we used to use

In C #, a delegate type is a type-safe, object-oriented function pointer. When we define a delegate type through the delegate keyword, the compiler generates three methods for the delegate type: Invoke, BeginInvoke, and EndInvoke.For example, for the following delegate type,