C# 如何在Xamarin.forms中显示边框边缘上的阴影？

目前，我希望我的框架元素的边缘在Xamarin XAML中显示为着色，使用框架元素的Hassadow属性，但它不起作用或标记差异，然后我将渲染自定义框架，如果它出来但不是着色，则将其作为第二行，我使用Android 7

Codigo XAML：

        <localframe:MyFrame 
           HasShadow="True" 
           ShadowColor="Red" 
           BorderColor="Red"
           BorderWidth="10"/>

Android中的代码渲染帧：

[assembly: ExportRenderer(typeof(MyFrame), typeof(FrameRendererMy))]
namespace xxxxxxxxxx.Droid
{
    [Obsolete]
    public class FrameRendererMy : FrameRenderer
    {

        public FrameRendererMy(Context context) : base(context)
        {

        }


        protected override void OnDraw(Canvas canvas)
        {

            var frame = Element as MyFrame;

            var my1stPaint = new Android.Graphics.Paint();
            var my2ndPaint = new Android.Graphics.Paint();
            var backgroundPaint = new Android.Graphics.Paint();

            my1stPaint.AntiAlias = true;
            my1stPaint.SetStyle(Paint.Style.Stroke);
            my1stPaint.StrokeWidth = frame.BorderWidth + 2;
            my1stPaint.Color = frame.BorderColor.ToAndroid();

            my2ndPaint.AntiAlias = true;
            my2ndPaint.SetStyle(Paint.Style.Stroke);
            my2ndPaint.StrokeWidth = frame.BorderWidth;
            my2ndPaint.Color = frame.BackgroundColor.ToAndroid();

            backgroundPaint.SetStyle(Paint.Style.Stroke);
            backgroundPaint.StrokeWidth = 4;
            backgroundPaint.Color = frame.BackgroundColor.ToAndroid();

            Rect oldBounds = new Rect();
            canvas.GetClipBounds(oldBounds);

            RectF oldOutlineBounds = new RectF();
            oldOutlineBounds.Set(oldBounds);

            RectF myOutlineBounds = new RectF();
            myOutlineBounds.Set(oldBounds);
            myOutlineBounds.Top += (int)my2ndPaint.StrokeWidth + 3;
            myOutlineBounds.Bottom -= (int)my2ndPaint.StrokeWidth + 3;
            myOutlineBounds.Left += (int)my2ndPaint.StrokeWidth + 3;
            myOutlineBounds.Right -= (int)my2ndPaint.StrokeWidth + 3;


            canvas.DrawRoundRect(oldOutlineBounds, 10, 10, backgroundPaint); //to "hide" old outline
            canvas.DrawRoundRect(myOutlineBounds, frame.CornerRadius, frame.CornerRadius, my1stPaint);
            canvas.DrawRoundRect(myOutlineBounds, frame.CornerRadius, frame.CornerRadius, my2ndPaint);

            base.OnDraw(canvas);
        }


    }
}

我相信这是一个以Xamarin.Forms形式出现的问题。他们还提到了Hassadow中的Android问题，Hassadow对Android没有影响

您可以使用它，这是一个非常好的、功能齐全的替代

框架

试试这段代码

    <StackLayout Margin="10">
    <Frame  CornerRadius="5"  Padding="8" HasShadow="True" Margin="10">
        <StackLayout>
            <Label Text="Frame Example" FontSize="Medium"  FontAttributes="Bold" />
            <BoxView Color="Gray" HeightRequest="2" HorizontalOptions="Fill" />
            <Label Text="Frames can wrap more complex layouts"/>
        </StackLayout>
    </Frame>
</StackLayout>

如果不起作用，请检查下面的答案

---

是否要为

边框绘制圆角矩形？如果你能提供一个屏幕截图或其他简单的关于你的需求？
    <StackLayout Margin="10">
    <Frame  CornerRadius="5"  Padding="8" HasShadow="True" Margin="10">
        <StackLayout>
            <Label Text="Frame Example" FontSize="Medium"  FontAttributes="Bold" />
            <BoxView Color="Gray" HeightRequest="2" HorizontalOptions="Fill" />
            <Label Text="Frames can wrap more complex layouts"/>
        </StackLayout>
    </Frame>
</StackLayout>