c# - 如何将属性附加到自定义事件？

Question

我有一个自定义事件并想为其附加一个属性(一个字符串就可以)。我的代码需要更改什么:

    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，您需要创建一个包含新属性的新 RoutedEventArgs 派生类。像这样的东西:

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，您必须创建一个使用新事件参数的委托(delegate):

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

之后，您必须对上面的代码进行更改，以便它使用这些新对象:

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);
}