C #에서 내 이벤트를 어떻게 만들 수 있습니까?

C #에서 내 이벤트를 어떻게 만들 수 있습니까?

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C #에서 내 이벤트를 어떻게 만들 수 있습니까?

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다음은 C #으로 이벤트를 만들고 사용하는 예입니다.

using System;

namespace Event_Example
{
    //First we have to define a delegate that acts as a signature for the
    //function that is ultimately called when the event is triggered.
    //You will notice that the second parameter is of MyEventArgs type.
    //This object will contain information about the triggered event.
    public delegate void MyEventHandler(object source, MyEventArgs e);

    //This is a class which describes the event to the class that recieves it.
    //An EventArgs class must always derive from System.EventArgs.
    public class MyEventArgs : EventArgs
    {
        private string EventInfo;
        public MyEventArgs(string Text)
        {
            EventInfo = Text;
        }
        public string GetInfo()
        {
            return EventInfo;
        }
    }

    //This next class is the one which contains an event and triggers it
    //once an action is performed. For example, lets trigger this event
    //once a variable is incremented over a particular value. Notice the
    //event uses the MyEventHandler delegate to create a signature
    //for the called function.
    public class MyClass
    {
        public event MyEventHandler OnMaximum;
        private int i;
        private int Maximum = 10;
        public int MyValue
        {
            get
            {
                return i;
            }
            set
            {
                if(value <= Maximum)
                {
                    i = value;
                }
                else
                {
                    //To make sure we only trigger the event if a handler is present
                    //we check the event to make sure it's not null.
                    if(OnMaximum != null)
                    {
                        OnMaximum(this, new MyEventArgs("You've entered " +
                            value.ToString() +
                            ", but the maximum is " +
                            Maximum.ToString()));
                    }
                }
            }
        }
    }

    class Program
    {
        //This is the actual method that will be assigned to the event handler
        //within the above class. This is where we perform an action once the
        //event has been triggered.
        static void MaximumReached(object source, MyEventArgs e)
        {
            Console.WriteLine(e.GetInfo());
        }

        static void Main(string[] args)
        {
            //Now lets test the event contained in the above class.
            MyClass MyObject = new MyClass();
            MyObject.OnMaximum += new MyEventHandler(MaximumReached);

            for(int x = 0; x <= 15; x++)
            {
                MyObject.MyValue = x;
            }

            Console.ReadLine();
        }
    }
}

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이벤트 기사 에서 이벤트 및 대리인에 대한 전체 토론이 있습니다 . 가장 간단한 종류의 이벤트의 경우 공개 이벤트를 선언하면 컴파일러가 이벤트와 필드를 모두 만들어 구독자를 추적합니다.

public event EventHandler Foo;

보다 복잡한 가입 / 가입 취소 논리가 필요한 경우 다음과 같이 명시 적으로 수행 할 수 있습니다.

public event EventHandler Foo
{
    add
    {
        // Subscription logic here
    }
    remove
    {
        // Unsubscription logic here
    }
}

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다음 코드를 사용하여 이벤트를 선언 할 수 있습니다.

public event EventHandler MyOwnEvent;

필요한 경우 EventHandler 대신 사용자 정의 대리자 유형을 사용할 수 있습니다.

이벤트 자습서 (MSDN) 기사에서 .NET의 이벤트 사용에 대한 자세한 정보 / 자습을 찾을 수 있습니다 .

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이를 위해서는 세 가지 구성 요소를 알아야합니다

1. 책임있는 곳 firing the Event
2. 책임있는 곳 responding to the Event

3. 이벤트 자체

   ㅏ. 행사

   b. EventArgs

   씨. EventArgs 열거

now lets create Event that fired when a function is called

but I my order of solving this problem like this: I'm using the class before I create it

1. the place responsible for responding to the Event

   NetLog.OnMessageFired += delegate(object o, MessageEventArgs args) 
   {
           // when the Event Happened I want to Update the UI
           // this is WPF Window (WPF Project)  
           this.Dispatcher.Invoke(() =>
           {
               LabelFileName.Content = args.ItemUri;
               LabelOperation.Content = args.Operation;
               LabelStatus.Content = args.Status;
           });
   };
   

NetLog is a static class I will Explain it later

the next step is

2. the place responsible for firing the Event

   //this is the sender object, MessageEventArgs Is a class I want to create it  and Operation and Status are Event enums
   NetLog.FireMessage(this, new MessageEventArgs("File1.txt", Operation.Download, Status.Started));
   downloadFile = service.DownloadFile(item.Uri);
   NetLog.FireMessage(this, new MessageEventArgs("File1.txt", Operation.Download, Status.Finished));
   

the third step

3. the Event itself

I warped The Event within a class called NetLog

public sealed class NetLog
{
    public delegate void MessageEventHandler(object sender, MessageEventArgs args);

    public static event MessageEventHandler OnMessageFired;
    public static void FireMessage(Object obj,MessageEventArgs eventArgs)
    {
        if (OnMessageFired != null)
        {
            OnMessageFired(obj, eventArgs);
        }
    }
}

public class MessageEventArgs : EventArgs
{
    public string ItemUri { get; private set; }
    public Operation Operation { get; private set; }
    public Status Status { get; private set; }

    public MessageEventArgs(string itemUri, Operation operation, Status status)
    {
        ItemUri = itemUri;
        Operation = operation;
        Status = status;
    }
}

public enum Operation
{
    Upload,Download
}

public enum Status
{
    Started,Finished
}

this class now contain the Event, EventArgs and EventArgs Enums and the function responsible for firing the event

sorry for this long answer

참고URL : https://stackoverflow.com/questions/623451/how-can-i-make-my-own-event-in-c