从所有类外面调用C＃事件？ [英] Calling C# events from outside the owning class?

问题描述

我目前的情况是这样的：

  public class CustomForm：Form 
 {
 public class CustomGUIElement 
 {
 ... 
 public event MouseEventHandler Click ; 
 //等，等等。 
 ... 
} 
 
私人列表< CustomGUIElement> _elements; 
 
 ... 
 
 public void CustomForm_Click（object sender，MouseEventArgs e）
 {
 //我们可能要调用其中一个_elements [ n]。点击这里
 //但是我们不能因为我们不在同一个类。 
} 
} 
  

我的第一个想法是有一个类似于

 内部枚举GUIElementHandlers {Click，...} 
 internal void CustomGUIElement :: CallHandler（GUIElementHandler h，object [ ] args）{
 switch（h）{
 case点击：
 this.Click（this，（EventArgs）args [0]）; 
 break; 
 ... // etc等等
} 
} 
  

这是一个可怕的丑陋的污泥，但它应该工作吗？一定要有一个更优雅的解决方案呢？ .NET库一直在使用消息处理程序，并在Control中调用事件。还有其他任何人有其他/更好的想法吗？

解决方案

你只需要添加一个调用事件的公共方法。微软已经为某些事件（例如执行点击）执行 。

  public class CustomGUIElement 
 {
 public void PerformClick（）
 {
 OnClick（EventArgs.Empty）; 
} 
 
 protected virtual void OnClick（EventArgs e）
 {
 if（Click！= null）
单击（this，e）; 
} 
} 
  

然后，您将在示例事件处理程序中执行以下操作...

  public void CustomForm_Click（object sender，MouseEventArgs e）
 {
 _elements [0] .PerformClick（）; 
} 
  

Is it possible under any set of circumstances to be able to accomplish this?

My current circumstances are this:

public class CustomForm : Form
{
    public class CustomGUIElement
    {
    ...
        public event MouseEventHandler Click;
        // etc, and so forth.
    ...
    }

    private List<CustomGUIElement> _elements;

    ...

    public void CustomForm_Click(object sender, MouseEventArgs e)
    {
        // we might want to call one of the _elements[n].Click in here
        // but we can't because we aren't in the same class.
    }
}

My first thought was to have a function similar to:

internal enum GUIElementHandlers { Click, ... }
internal void CustomGUIElement::CallHandler(GUIElementHandler h, object[] args) {
    switch (h) {
        case Click:
            this.Click(this, (EventArgs)args[0]);
            break;
        ... // etc and so forth
    }
}

It's a horribly ugly kludge, but it should work... There must be a more elegant solution though? The .NET library does this all the time with message handlers and calling events in Control's. Does anyone else have any other/better ideas?

解决方案

You just need to add a public method for invoking the event. Microsoft already does this for some events such as PerformClick for controls that expose a Click event.

public class CustomGUIElement    
{
    public void PerformClick()
    {
        OnClick(EventArgs.Empty);
    }

    protected virtual void OnClick(EventArgs e)
    {
        if (Click != null)
            Click(this, e);
    }
}

You would then do the following inside your example event handler...

public void CustomForm_Click(object sender, MouseEventArgs e)        
{
    _elements[0].PerformClick();
}

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