Question

我想要一个仅将enum作为参数的事件。例如

public enum MyEvents{
   Event1
}

// how do I declare this to take enum MyEvents as argument
public static event EventHandler EventTriggered;

public static void Trigger(MyEvent event )
{
    if (EventTriggered != null)
    {
        EventTriggered(event);
    }
}

Answer 1

EventHandler收到EventArgs作为参数。要解决您的问题，您可以构建自己的MyEventArgs。

 public enum MyEvents
 { 
    Event1 
 }

 public class MyEventArgs : EventArgs
 {
    public MyEvents MyEvent { get; set; }
 }

 public static event EventHandler<MyEventArgs> EventTriggered; 

 public static void Trigger(MyEvents ev) 
 { 
     if (EventTriggered != null) 
     {
         EventTriggered(null, new MyEventArgs { MyEvent = ev });
     } 
 }

Answer 2

您为参数声明了委托：

public enum MyEvents { Event1 }

public delegate void MyEventHandler(MyEvents e);

public static event MyEventHandler EventTriggered;

虽然框架中的所有事件都采用了EventArgs的参数，但您可以使用您喜欢的任何参数。但是，人们可能会期望框架中使用的模式，这可能会使您的代码更难以遵循。

Answer 3

我可能会在游戏中迟到，但是如何：

public event Action<MyEvent> EventTriggered = delegate { }; 

private void Trigger(MyEvent e) 
{ 
     EventTriggered(e);
}

将事件设置为匿名委托可以避免我检查事件是否为空。

我发现这在使用MVVM时很方便，就像使用ICommand.CanExecute方法一样。

Answer 4

您需要声明自定义事件处理程序。

public class MyEventArgs: EventArgs
{
  ...
}

public delegate void MyEventHandler(object sender, MyEventArgs e);

public class MyControl: UserControl
{
  public event MyEventHandler MyEvent;
   ...
}

Answer 5

这是您的样本的改造，以帮助您入门。

你的样本有一个静态事件 - 事件来自一个类实例更常见，但我在下面保持静态。
下面的示例还使用更标准的命名OnXxx来提升事件。
下面的示例不考虑线程安全性，如果您坚持认为事件是静态的，这可能会成为一个问题。

public enum MyEvents{ 
     Event1 
} 

public class MyEventArgs : EventArgs
{
    public MyEventArgs(MyEvents myEvents)
    {
        MyEvents = myEvents;
    }

    public MyEvents MyEvents { get; private set; }
}

public static class MyClass
{
     public static event EventHandler<MyEventArgs> EventTriggered; 

     public static void Trigger(MyEvents myEvents) 
     {
         OnMyEvent(new MyEventArgs(myEvents));
     }

     protected static void OnMyEvent(MyEventArgs e)
     {
         if (EventTriggered != null)
         {
             // Normally the first argument (sender) is "this" - but your example
             // uses a static event, so I'm passing null instead.
             // EventTriggered(this, e);
             EventTriggered(null, e);
         } 
     }
}

Answer 6

public enum MyEvents
{
    Event1
}

public class CustomEventArgs : EventArgs
{
    public MyEvents MyEvents { get; set; }
}


private EventHandler<CustomEventArgs> onTrigger;

public event EventHandler<CustomEventArgs> Trigger
{
    add
    {
        onTrigger += value;
    }
    remove
    {
        onTrigger -= value;
    }
}

protected void OnTrigger(CustomEventArgs e)
{
    if (onTrigger != null)
    {
        onTrigger(this, e);
    }
}

Answer 7

没有参数的示例：

delegate void NewEventHandler();
public event NewEventHandler OnEventHappens;

从另一个班级开始，您可以订阅

otherClass.OnEventHappens += ExecuteThisFunctionWhenEventHappens;

并声明不带参数的函数。

带有自定义参数的C＃事件

7 个答案: