如何写一个触发器？ [英] How to write a Trigger?

问题描述

我需要如何处理这个问题？

  class MyClass {
 
 ManualResetEvent mre; 
 
 public MyClass（）{
 mre = new ManualResetEvent（false）; 
 Data = null; 
} 
 
 public object Data {get;组; } 
 
 void DataSet（object sender，EventArgs e）{
 Console.WriteLine（object Data has been set。）; 
 mre.Set（）; 
} 
 
} 
  

代表似乎不是我需要的。一个事件，也许？如果这样做，我该怎么写？

  MyClass mc; 
 
 void processA（）{
 mc = new MyClass（）; 
 mc.Data = GetDataFromLongProcess（）; 
} 
  

解决方案

 私有对象数据; 
 public object Data {
 get {return data;} 
 set {
 if（value！= data）{
 data = value; 
 OnDataChanged（）; 
} 
} 
} 
 protected virtual void OnDataChanged（）{
 EventHandler handler = DataChanged; 
 if（handler！= null）handler（this，EventArgs.Empty）; 
} 
 public event EventHandler DataChanged; 
  

然后将任何代码挂接到 DataChanged 事件。例如：

  MyClass mc = ... 
 mc.DataChanged + = delegate {
控制台。 WriteLine（new data！wow！）; 
}; 
  

I want my C# code to call an event whenever a value is assigned to my object.

How exactly would I need to go about that?

class MyClass {

  ManualResetEvent mre;

  public MyClass() {
    mre = new ManualResetEvent(false);
    Data = null;
  }

  public object Data { get; set; }

  void DataSet(object sender, EventArgs e) {
    Console.WriteLine("object Data has been set.");
    mre.Set();
  }

}

Delegates don't seem to be what I need. An event, maybe? How would I write such an event, if so?

MyClass mc;

void processA() {
  mc = new MyClass();
  mc.Data = GetDataFromLongProcess();
}

解决方案

private object data;
public object Data {
    get { return data;}
    set {
        if(value != data) {
            data = value;
            OnDataChanged();
        }
    }
}
protected virtual void OnDataChanged() {
    EventHandler handler = DataChanged;
    if(handler != null) handler(this, EventArgs.Empty);
}
public event EventHandler DataChanged;

then hook any code to the DataChanged event. For example:

MyClass mc = ...
mc.DataChanged += delegate {
    Console.WriteLine("new data! wow!");
};

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