WPF 将路径添加到 ContentControl 在运行时不起作用

Question

您有一个程序可以在运行时将任何对象添加到画布。我根据要求使用 ContentControl。 ContentControl 将附加到拖动、调整大小和旋转，这就是我们不能使用其他对象的原因。项目将在运行时添加，所有创建的控件将在最后添加到画布上。下面的代码简单地添加了两个对象，一个椭圆和一个几何。椭圆显示在画布中，但不显示几何。但是，如果直接添加到 XAML 中，则会显示。如果在代码中直接将路径添加为画布的子级，它也可以工作。请帮忙。添加到 ContentControl 时如何在运行时通过代码显示此几何形状。

不起作用

C#

  public partial class Window1 : Window
    {
        
        public Window1()
        {
            InitializeComponent();
            AddItemsToCanvas();
        }

        void AddItemsToCanvas()
        {
            //add Ellipse
            var contentControl = new ContentControl();
            contentControl.Width = 130;
            contentControl.Height = 130;
            contentControl.MinHeight = 5;
            contentControl.MinWidth = 5;
            Canvas.SetTop(contentControl, 50);
            Canvas.SetLeft(contentControl, 100);
            var ellipse = new Ellipse { Fill = Brushes.Blue, Stretch = Stretch.Fill, IsHitTestVisible = false };
            var border = new Border { Background = Brushes.Transparent, VerticalAlignment = VerticalAlignment.Stretch, HorizontalAlignment = HorizontalAlignment.Stretch };
            border.Child = ellipse;
            contentControl.Content = border;
            canvas.Children.Add(contentControl);

            //add geometry. This doesn't work.
            var contentGeomControl = new ContentControl();
            contentGeomControl.Width = 130;
            contentGeomControl.Height = 130;
            contentGeomControl.MinHeight = 5;
            contentGeomControl.MinWidth = 5;
            Canvas.SetTop(contentGeomControl, 50);
            Canvas.SetLeft(contentGeomControl, 100);
            var streamGeometry = StreamGeometry.Parse("M150,300 L300,300 A150,150 0 0 0 256,194 z");
            var path = new Path { Data = streamGeometry, Fill = Brushes.Wheat, IsHitTestVisible = false };
            var borderGeom = new Border { Background = Brushes.Transparent, VerticalAlignment = VerticalAlignment.Stretch, HorizontalAlignment = HorizontalAlignment.Stretch };
            borderGeom.Child = path;
            contentGeomControl.Content = borderGeom;
            canvas.Children.Add(contentGeomControl);
        }
    }
}

XAML

<Window x:Class="DiagramDesigner.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    WindowStartupLocation="CenterScreen"
    Title="Move, resize and rotate"
    Height="550" Width="750" Name="Win1">
<Window.Resources>
 <Canvas Name="canvas" Background="White" Opacity="99">
    
</Canvas>

这可行，但我们需要在运行时添加项目

XAML

<Canvas Name="canvas" Background="White" Opacity="99">
    <ContentControl>
        <ContentControl.Content>
            <Border >
                <Path Fill="Wheat" Data="M150,300 L300,300 A150,150 0 0 0 256,194 z"/>
            </Border>
        </ContentControl.Content>
    </ContentControl>
</Canvas>

Answer 1

您正在代码中设置 Width、Height、MinHeight、MinWidth、Canvas.Top 和 Canvas.Left 属性，但不在 XAML 中。这就是区别。尝试删除这些行：

var contentGeomControl = new ContentControl();
var streamGeometry = StreamGeometry.Parse("M150,300 L300,300 A150,150 0 0 0 256,194 z");
var path = new Path { Data = streamGeometry, Fill = Brushes.Wheat, IsHitTestVisible = false };
var borderGeom = new Border { Background = Brushes.Transparent, VerticalAlignment = VerticalAlignment.Stretch, HorizontalAlignment = HorizontalAlignment.Stretch };
borderGeom.Child = path;
contentGeomControl.Content = borderGeom;
canvas.Children.Add(contentGeomControl);

那么您应该会看到相同的结果。