具有自定义类型的UIButton丢失单击事件

Question

我有以下用Xamarin创建自定义iOS UIButton的代码：

    protected override void OnElementChanged(ElementChangedEventArgs<Button> e)
    {
        // will have to create a native Custom type of ios button to avoid text dimming
        // when touched

        // logic of element processing from
        // https://developer.xamarin.com/guides/xamarin-forms/custom-renderer/view/

        // except we don't call the base immediately
        // because it will create the Control for us, but we don't want that here
        if (Control == null)
        {
            // instantiate the native control and assign it to the Control property with
            // the SetNativeControl method
            uiBtn = new UIButton(UIButtonType.Custom);
            SetNativeControl(uiBtn); // should set Control to the newly created element 
            // and prevent base.OnElementChanged(e) from creating a new element instead
        }

        base.OnElementChanged(e);

        // some button customization code here - it does not matter, the issue happens also without it...

渲染器代码运行良好，但现在我在Xamarin.Forms按钮上没有收到任何单击的事件。

如何恢复丢失的点击功能？

Answer 1

最后，在Xamarin源代码中，我发现了这个：

https://github.com/xamarin/Xamarin.Forms/blob/2d9288eee6e6f197364a64308183725e7bd561f9/Xamarin.Forms.Platform.iOS/Renderers/ButtonRenderer.cs

看看OnElementChanged，我有点惊讶，只有当OnElementChanged的这个实例创建原生元素时，才会附加事件。不确定为什么要这样做，但至少现在我知道，如果我自己创建一个控件，那么我将不得不自己连接click事件。