c# – 在Custom Usercontrol – Window Store App中公开事件

我似乎在Xaml中暴露事件时遇到了问题.我在自定义用户控件中声明了一个公共事件处理程序.

public sealed partial class FoodItemControl : UserControl
{
    public event EventHandler<StringEventArgs> thumbnailClicked;

    public FoodItemControl()
    {
        InitializeComponent();
        (this.Content as FrameworkElement).DataContext = this;
    }



    private void Thumbnail_Tapped(object sender,TappedRoutedEventArgs e)
    {
        var handler = thumbnailClicked;
        if (handler != null)
        {
            handler(this,new StringEventArgs());
        }
    }
}

但是当我在xaml中为它分配事件时,无法找到暴露的事件处理程序.即

<local:FoodItemControl thumbnailClicked="SOMETHING" />

我在发现的例子中遗漏了什么吗？

编辑：我的问题似乎是我将事件定义为EventHandler< StringEventArgs>.一旦我将其改为简单的EventHandler I.e

public event EventHandler thumbnailedClicked;

但是我还是不明白为什么？

解决方法

您必须创建依赖项属性并注册该属性以在用户控件中公开它：

public sealed partial class FoodItemControl : UserControl
{
    public EventHandler thumbnailClicked
    {
        get { return (EventHandler)GetValue(thumbnailClickedProperty); }
        set { SetValue(thumbnailClickedProperty,value); }
    }

    public static readonly DependencyProperty thumbnailClickedProperty =
  DependencyProperty.Register("thumbnailClicked",typeof(EventHandler),typeof(FoodItemControl),new PropertyMetadata(""));


    public FoodItemControl()
    {
        this.InitializeComponent();
        (this.Content as FrameworkElement).DataContext = this;
    }
}