Question

我可以将ContentControl的Content属性设置为DrawingVisual对象吗？它在文档中说，内容可以是任何东西，但我尝试过，当我将控件添加到画布时没有任何显示。是否可以，如果可以，您可以发布将ContentControl（其内容为DrawingVisual）添加到画布的完整代码吗？

Answer 1

我可以将ContentControl的Content属性设置为DrawingVisual对象吗？

技术上，是的，你可以。但是，这可能不是你想要的。添加到ContentControl的DrawingVisual将只显示字符串“System.Windows.Media.DrawingVisual”。网格中的以下代码将证明这一点：

<Button>
    <DrawingVisual/>
</Button>

要正确使用DrawingVisual，您需要将其封装在FrameworkElement中。请参阅Microsoft Reference。

因此，以下代码应该有助于做你想要的。

<Window x:Class="TestDump.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:TestDump"
Title="Window1" Height="300" Width="600" >
<Grid>
    <Canvas>
        <Button >
            <local:MyVisualHost Width="600" Height="300"/>
        </Button>
    </Canvas>
</Grid>
</Window>

在C＃方面：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace TestDump
{
/// <summary>
/// Interaction logic for Window1.xaml
/// </summary>
public partial class Window1 : Window
{
    public Window1()
    {
        InitializeComponent();
    }
}

public class MyVisualHost : FrameworkElement
{
    private VisualCollection _children;
    public MyVisualHost()
    {
        _children = new VisualCollection(this);
        _children.Add(CreateDrawingVisualRectangle());
    }
    // Create a DrawingVisual that contains a rectangle.
    private DrawingVisual CreateDrawingVisualRectangle()
    {
        DrawingVisual drawingVisual = new DrawingVisual();

        // Retrieve the DrawingContext in order to create new drawing content.
        DrawingContext drawingContext = drawingVisual.RenderOpen();

        // Create a rectangle and draw it in the DrawingContext.
        Rect rect = new Rect(new System.Windows.Point(160, 100), new System.Windows.Size(320, 80));
        drawingContext.DrawRectangle(System.Windows.Media.Brushes.Blue, (System.Windows.Media.Pen)null, rect);

        // Persist the drawing content.
        drawingContext.Close();

        return drawingVisual;
    }

    // Provide a required override for the VisualChildrenCount property.
    protected override int VisualChildrenCount
    {
        get { return _children.Count; }
    }

    // Provide a required override for the GetVisualChild method.
    protected override Visual GetVisualChild(int index)
    {
        if (index < 0 || index >= _children.Count)
        {
            throw new ArgumentOutOfRangeException();
        }

        return _children[index];
    }

}
}

WPF - 作为DrawingVisual的ContentControl内容

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