为了能够创建需要在Xamarin环境中本机完成的样式，我使用的是自定义渲染器 . 在android方面，我收到 System.InvalidCastException ，我不知道如何解决这个问题 . 我正在包装 Android.Widget.StackView 由于this guys建议我之前得到的错误（没有默认构造函数接受0参数错误） . 由于声明或实例化，似乎没有发生错误，而是当我将它添加到ContentView并在返回时发生（通过注释掉行，如下所示） .

MainPage = new ContentPage {
            Content = new StackLayout {
                VerticalOptions = LayoutOptions.Center,
                Children = {
                    item1,
                    item2,
                    item3,
                    item4,
                    item5,
                    item6,
                    //rendererIWantToAdd,//taking out this line make it work. adding it breaks it
                }
            }
        };

代码

RendererView

public class RendererView :  View
{

    public static readonly BindableProperty ImageProperty = BindableProperty.Create(
        propertyName: "Src",
        returnType: typeof(string),
        declaringType: typeof(string),
        defaultValue: ""
    );
    public String Src
    {
        get { return (string)GetValue(ImageProperty); }
        set { SetValue(ImageProperty, value); }
    }

    public static readonly BindableProperty TextProperty = BindableProperty.Create(
        propertyName: "Text",
        returnType: typeof(string),
        declaringType: typeof(string),
        defaultValue: "Hello World"
    );
    public String Text
    {
        get { return (string)GetValue(TextProperty); }
        set { SetValue(TextProperty, value); }
    }

    public static readonly BindableProperty ColorProperty = BindableProperty.Create(
        propertyName: "Color",
        returnType: typeof(string),
        declaringType: typeof(string),
        defaultValue: "#AAAAAA"
    );
    public String Color
    {
        get { return (string) GetValue(ColorProperty); }
        set { SetValue(ColorProperty, value); }
    }
}

RendererViewAndroid

[assembly: ExportRenderer(typeof(Project.RendererView), typeof(stackViewWrapper))]
namespace Project.Droid
{
    public class RendererViewAndroid : ViewRenderer<RendererView, stackViewWrapper>
    {

        Android.Widget.TextView label;
        Android.Widget.ImageView image;

        protected override void OnElementChanged(ElementChangedEventArgs<RendererView> e)
        {
            base.OnElementChanged(e);
            if (Control == null)
            {
                createItem(e);
            }

            if (e.OldElement != null)
            {

                unsubscribe(e);
            }

            if (e.NewElement != null)
            {
                subscribe(e);
            }



        }


        protected void createItem(ElementChangedEventArgs<RendererView> e)
        {


            SetNativeControl(new stackViewWrapper());
            label = new Android.Widget.TextView(Context)
            {
                Text = Element.Text
            };

            image = new Android.Widget.ImageView(Context);
            if (!string.IsNullOrWhiteSpace(Element.Src))
            {
                Context.Resources.GetBitmapAsync(Element.Src).ContinueWith((t) =>
                {
                    var bitmap = t.Result;
                    if (bitmap != null)
                    {
                        image.SetImageBitmap(bitmap);
                        bitmap.Dispose();
                    }
                }, TaskScheduler.FromCurrentSynchronizationContext());

            }
            else {
            //  // clear the image
                image.SetImageBitmap(null);
            }


            Control.AddView(image);
            Control.AddView(label);



        }
        protected void subscribe(ElementChangedEventArgs<RendererView> e)
        {

        }
        protected void unsubscribe(ElementChangedEventArgs<RendererView> e)
        {

        }





        protected override void Dispose(bool disposing)
        {
            base.Dispose(disposing);
        }





    }


    public  class stackViewWrapper : Android.Views.View
    {
        public stackViewWrapper() : base(Android.App.Application.Context)
        {
        }
    }
}

错误堆栈跟踪

System.InvalidCastException：指定的强制转换无效 . at at（wrapper castclass）System.Object：__ castclass_with_cache（object，intptr，intptr）at Xamarin.Forms.Registrar1 [TRegistrable] .GetHandler（System.Type type）[0x0001b] in C：\ BuildAgent2 \ work \ aad494dc9bc9783 \ Xamarin . Forms.Core \ Registrar.cs：24 at Xamarin.Forms.Registrar1 [TRegistrable] .GetHandler [TOut]（System.Type type）[0x00000]在C：\ BuildAgent2 \ work \ aad494dc9bc9783 \ Xamarin.Forms.Core \ Registrar . cs：29位于C：\ BuildAgent2 \ work \ aad494dc9bc9783 \ Xamarin.Forms.Platform.Android \ Platform.cs：281 at的Xamarin.Forms.Platform.Android.Platform.CreateRenderer（Xamarin.Forms.VisualElement element）[0x00006] Xamarin.Forms.Platform.Android.VisualElementPackager.AddChild（Xamarin.Forms.VisualElement视图，IVisualElementRenderer oldRenderer，Xamarin.Forms.Platform.Android.RendererPool池，布尔sameChildren）[0x00023]在C：\ BuildAgent2 \ work \ aad494dc9bc9783 \ Xamarin中.Forms.Platform.Android \ VisualElementPackager.cs：72 at Xamarin.Forms.Platform.Android.VisualElementPackager.SetElement（Xamarin.Forms.Visual）元素oldElement，Xamarin.Forms.VisualElement newElement）[0x00104]在C：\ BuildAgent2 \ work \ aad494dc9bc9783 \ Xamarin.Forms.Platform.Android \ VisualElementPackager.cs：204 at Xamarin.Forms.Platform.Android.VisualElementPackager.Load（） [0x00000]位于C：\ BuildAgent2 \ work \ aad494dc9bc9783 \ Xamarin.Forms.Platform.Android \ VisualElementPackager.cs：56，位于Xamarin.Forms.Platform.Android.VisualElementRenderer1 [TElement] .SetPackager（Xamarin.Forms.Platform.Android . VisualElementPackager packager）[0x00007]在C：\ BuildAgent2 \ work \ aad494dc9bc9783 \ Xamarin.Forms.Platform.Android \ VisualElementRenderer.cs：327 at Xamarin.Forms.Platform.Android.VisualElementRenderer1 [TElement] .SetElement（Xamarin.Forms.Platform .Android.Telement元素）[0x00111]在C：\ BuildAgent2 \ work \ aad494dc9bc9783 \ Xamarin.Forms.Platform.Android \ VisualElementRenderer.cs：195 at Xamarin.Forms.Platform.Android.VisualElementRenderer1 [TElement] .Xamarin.Forms . Platform.Android.IVisualElementRenderer.SetElement（Xamarin.Forms.VisualElement元素） [0x00027]在X：\ BuildAgent2 \ work \ aad494dc9bc9783 \ Xamarin.Forms.Platform.Android \ VisualElementRenderer.cs：128中的Xamarin.Forms.Platform.Android.Platform.CreateRenderer（Xamarin.Forms.VisualElement element）[0x0001f] in C：\ BuildAgent2 \ work \ aad494dc9bc9783 \ Xamarin.Forms.Platform.Android \ Platform.cs：282 at Xamarin.Forms.Platform.Android.VisualElementPackager.AddChild（Xamarin.Forms.VisualElement view，IVisualElementRenderer oldRenderer，Xamarin.Forms.Platform .Android.RendererPool pool，Boolean sameChildren）[0x00023]在C：\ BuildAgent2 \ work \ aad494dc9bc9783 \ Xamarin.Forms.Platform.Android \ VisualElementPackager.cs：72 at Xamarin.Forms.Platform.Android.VisualElementPackager.SetElement（Xamarin . 在Xamarin.Forms.Platform.Android.VisualElementPackager.Load的C：\ BuildAgent2 \ work \ aad494dc9bc9783 \ Xamarin.Forms.Platform.Android \ VisualElementPackager.cs：204中的Forms.VisualElement oldElement，Xamarin.Forms.VisualElement newElement）[0x00104] （）[0x00000]在C：\ BuildAgent2 \ work \ aad494dc9bc9783 \ Xamarin.Forms中.Platform.Android \ VisualElementPackager.cs：56位于C：\ BuildAgent2 \ work \ aad494dc9bc9783中的Xamarin.Forms.Platform.Android.VisualElementRenderer1 [TElement] .SetPackager（Xamarin.Forms.Platform.Android.VisualElementPackager packager）[0x00007] Xamarin.Forms.Platform.Android \ VisualElementRenderer.cs：327在C：\ BuildAgent2 \ work中的Xamarin.Forms.Platform.Android.VisualElementRenderer1 [TElement] .SetElement（Xamarin.Forms.Platform.Android.TElement element）[0x00111] \ aad494dc9bc9783 \ Xamarin.Forms.Platform.Android \ VisualElementRenderer.cs：195 at Xamarin.Forms.Platform.Android.VisualElementRenderer1 [TElement] .Xamarin.Forms.Platform.Android.IVisualElementRenderer.SetElement（Xamarin.Forms.VisualElement element）[0x00027]在X：\ BuildAgent2 \ work \ aad494dc9bc9783 \ Xamarin.Forms.Platform.Android \ VisualElementRenderer.cs：128中的Xamarin.Forms.Platform.Android.Platform.CreateRenderer（Xamarin.Forms.VisualElement element）[0x0001f] in C：\ BuildAgent2 \ work \ aad494dc9bc9783 \ Xamarin.Forms.Platform.Android \ Platform.cs：282 at Xamarin.Forms.Platform.Android.Platform.AddChild（Xamarin.Forms.VisualElement view，Boolean layout）[0x00015] in C ：\ BuildAgent2 \ work \ aad494dc9bc9783 \ Xamarin.Forms.Platform.Android \ Platform.cs：518，位于C：\ BuildAgent2中的Xamarin.Forms.Platform.Android.Platform.SetPage（Xamarin.Forms.Page newRoot）[0x00089] work \ aad494dc9bc9783 \ Xamarin.Forms.Platform.Android \ Platform.cs：406 at Xamarin.Forms.Platform.Android.FormsApplicationActivity.InternalSetPage（Xamarin.Forms.Page page）[0x000b7] in C：\ BuildAgent2 \ work \ aad494dc9bc9783 \ Xamarin.Forms.Platform.Android \ FormsApplicationActivity.cs：286在C：\ BuildAgent2 \ work \ aad4中的Xamarin.Forms.Platform.Android.FormsApplicationActivity.SetMainPage（）[0x00000] 94dc9bc9783 \ Xamarin.Forms.Platform.Android \ FormsApplicationActivity.cs：305在C：\ BuildAgent2 \ work \ aad494dc9bc9783 \ Xamarin中的Xamarin.Forms.Platform.Android.FormsApplicationActivity.LoadApplication（Xamarin.Forms.Application应用程序）[0x0002d] . 在/Users/ryan/project-app-xamarin/Project/Project.Droid/MainActivity中的Project.Droid.MainActivity.OnCreate（Android.OS.Bundle包）[0x000ae]中的Forms.Platform.Android \ FormsApplicationActivity.cs：108 . cs：47在Android.App.Activity.n_OnCreate_Landroid_os_Bundle_（IntPtr jnienv，IntPtr native__this，IntPtr native_savedInstanceState）[0x00011] /Users/builder/data/lanes/3340/4e275588/source/monodroid/src/Mono.Android/platforms/ android-23 / src / generated / Android.App.Activity.cs：2426 at at（wrapper dynamic-method）System.Object：688deba4-7150-4f17-9062-10e53a94164c（intptr，intptr，intptr）