我如何将属性附加到自定义事件？

Question

我有一个自定义事件，并希望附加一个属性（一个字符串将罚款）。 什么我需要在我的代码更改：

public static readonly RoutedEvent ModelClickEvent = EventManager.RegisterRoutedEvent(
     "ModelClick", RoutingStrategy.Bubble, typeof(RoutedEventHandler), typeof(InfoBox)); 

    // Provide CLR accessors for the event 
    public event RoutedEventHandler FadeIn 
    { 
     add { AddHandler(ModelClickEvent, value); } 
     remove { RemoveHandler(ModelClickEvent, value); } 
    } 

    // This method raises the Tap event 
    void RaiseTapEvent() 
    { 
     RoutedEventArgs newEventArgs = new RoutedEventArgs(InfoBox.FadeInEvent); 
     RaiseEvent(newEventArgs); 
    } 

Answer 1

首先，你需要创建一个包含新特性新RoutedEventArgs派生类。喜欢的东西：

public class ModelClickEventArgs : RoutedEventArgs 
{ 
    public string MyString { get; set; } 
    public ModelClickEventArgs() : base() { } 
    public ModelClickEventArgs(RoutedEvent routedEvent) : base(routedEvent) { } 
    public ModelClickEventArgs(RoutedEvent routedEvent, object source) : base(routedEvent, source) { } 
} 

然后，你必须创建一个使用新的事件参数的委托：

public delegate void ModelClickEventHandler(object sender, ModelClickEventArgs e); 

之后，你将不得不做出上述更改您的代码，以便它使用这些新的对象：

public static readonly RoutedEvent ModelClickEvent = EventManager.RegisterRoutedEvent(
     "ModelClick", RoutingStrategy.Bubble, typeof(ModelClickEventHandler), typeof(Window)); 

// Provide CLR accessors for the event 
public event ModelClickEventHandler FadeIn 
{ 
    add { AddHandler(ModelClickEvent, value); } 
    remove { RemoveHandler(ModelClickEvent, value); } 
} 

// This method raises the Tap event 
void RaiseTapEvent() 
{ 
    ModelClickEventArgs newEventArgs = new ModelClickEventArgs(); 
    newEventArgs.MyString = "some string"; 
    RaiseEvent(newEventArgs); 
} 

Answer 2

如果你的意思是你想一个属性添加到R​​outedEventArgs对象的处理程序接收，那么所有你需要做的就是宣布自RoutedEventArgs继承的类并有你想添加的属性（-y/-ies）。

它看起来像下面这样：

public class ModelRoutedEventArgs : RoutedEventArgs 
{ 
    public string ExtraMessage { get; set; } 
    public ModelRoutedEventArgs(RoutedEvent routedEvent, string message) : base(routedEvent) 
    { 
    ExtraMessage = message; 
    } 
    // anything else you'd like to add can go here 
} 

或者，而不是添加一个构造函数重载，你可以实例化您的自定义RoutedEventArgs类，并把它传递给RaiseEvent()调用之前设置该属性。