HOW TO：實作鬆散耦合的事件

程式碼範例

以下程序與範例示範如何實作事件類別和事件接收 (Event Sink)，它們會實作通用事件介面以及引發事件的發行者 (Publisher)。如需使用 COM+ 鬆散耦合事件模型的詳細資訊，請參閱鬆散耦合的事件。

實作鬆散耦合的事件

1. 定義事件介面。例如，以下程式碼定義名為 IlceMsg 的事件介面，它含有名為 EventMethod 的方法。

   Public Interface ILceMsg
       Sub EventMethod(message As String)
   End Interface
   

   public interface ILceMsg
   {
       void EventMethod(string message);
   }
   

2. 定義從 System.EnterpriseServices.ServicedComponent 類別衍生且實作步驟 1 中定義之事件介面的事件類別。例如，以下程式碼定義名為 LceClass 的事件類別。

   <EventClass()> _
   Public Class LceClass 
   Inherits ServicedComponent Implements ILceMsg 
       Public Sub EventMethod(message As String) implements _
           ILceMsg.EventMethod
       End Sub 
   End Class
   

   [EventClass]
   public class LceClass : ServicedComponent, ILceMsg
   {
       public void EventMethod(string message){}
   }
   

3. 定義從 System.EnterpriseServices.ServicedComponent 類別衍生且實作步驟 1 中定義之事件介面的事件接收類別。例如，以下程式碼定義名為 LceSink 的事件接收類別。

   <EventClass()> _
   Public Class LceSink 
       Inherits ServicedComponent Implements ILceMsg 
         Public Sub EventMethod(message As String) implements _
               ILceMsg.EventMethod
            MessageBox.Show(message, "Event sink")
         End Sub
   End Class
   

   public class LceSink : ServicedComponent, ILceMsg
   {
       public void EventMethod(string message)
       {
           MessageBox.Show(message, "Event sink");
       }
   }
   

4. 建立事件發行者以觸發 LCE。

   Protected Sub Fire_Click(sender As Object, e As System.EventArgs)_
   Handles fireEvent.Click
         Dim evt As ILceMsg = CType(New LceClass(), ILceMsg)
         evt.EventMethod("Hello events")
   End Sub 
   

   protected void Fire_Click (object sender, System.EventArgs e)
   {
         ILceMsg evt = (ILceMsg) new LceClass();
         evt.EventMethod("Hello events");
   }
   

範例

Imports System
Imports System.IO
Imports System.Reflection
Imports System.EnterpriseServices
Imports System.Runtime.InteropServices

<assembly: ApplicationName("EventDemo")>
<assembly: ApplicationActivation(ActivationOption.Library)>
<assembly: AssemblyKeyFile("EventDemoSvr.snk")>

Namespace EventDemo
   Public Interface ILceMsg
      Sub EventMethod(message As String)
   End Interface    
      <EventClass()> _
      Public Class LceClass 
Inherits ServicedComponent Implements ILceMsg 
      Public Sub EventMethod(message As String) implements _
            ILceMsg.EventMethod
      End Sub 
   End Class 
    
   Public Class LceSink 
   Inherits ServicedComponent Implements ILceMsg 
      Public Sub EventMethod(message As String) implements _
            ILceMsg.EventMethod
         MessageBox.Show(message, "Event sink")
      End Sub
   End Class 
End Namespace 

using System;
using System.IO;
using System.Reflection;
using System.EnterpriseServices;
using System.Runtime.InteropServices;

[assembly: ApplicationName("EventDemo")]
[assembly: ApplicationActivation(ActivationOption.Library)]
[assembly: AssemblyKeyFile("EventDemoSvr.snk")]

namespace EventDemo
{
    public interface ILceMsg
    {
        void EventMethod(string message);
    }

    [EventClass]
    public class LceClass : ServicedComponent, ILceMsg
    {
        public void EventMethod(string message){}
    }

    public class LceSink : ServicedComponent, ILceMsg
    {   
        public void EventMethod(string message)
        {
            MessageBox.Show(message, "Event sink");
        }
    }
}

Publisher
Protected Sub Fire_Click(sender As Object, e As System.EventArgs)_
Handles fireEvent.Click
      Dim evt As ILceMsg = CType(New LceClass(), ILceMsg)
      evt.EventMethod("Hello events")
End Sub 

//Publisher
protected void Fire_Click (object sender, System.EventArgs e)
{
      ILceMsg evt = (ILceMsg) new LceClass();
      evt.EventMethod("Hello events");
}

請參閱

參考

System.EnterpriseServices Namespace

概念

鬆散耦合的事件
可用 COM+ 服務摘要

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