演练:使用 WindowsFormsHost 元素映射属性

本演练演示如何使用PropertyMap 属性将 WPF 属性映射到托管 Windows 窗体控件上的相应属性。

本演练涉及以下任务:

  • 创建项目。

  • 定义应用程序布局。

  • 定义新的属性映射。

  • 删除默认属性映射。

  • 替换默认属性映射。

  • 扩展默认属性映射。

完成后,你将能够将 WPF 属性映射到托管 Windows 窗体控件上的相应属性。

先决条件

你需要满足以下条件才能完成本演练:

  • Visual Studio 2017

创建并设置项目

  1. 创建一个名为 PropertyMappingWithWfhSample 的 WPF 应用项目

  2. 在解决方案资源管理器中,添加对 WindowsFormsIntegration 程序集的引用,该程序集名为 WindowsFormsIntegration.dll

  3. 在解决方案资源管理器中,添加对 System.Drawing 和 System.Windows.Forms 程序集的引用

定义应用程序布局

基于 WPF 的应用程序使用 WindowsFormsHost 元素托管 Windows 窗体控件。

定义应用程序布局

  1. 在 WPF 设计器中打开 Window1.xaml。

  2. 用下面的代码替换现有代码。

    <Window x:Class="PropertyMappingWithWfh.Window1"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="PropertyMappingWithWfh" Height="300" Width="300"
        Loaded="WindowLoaded">
      <DockPanel Name="panel1" LastChildFill="True">
        <WindowsFormsHost Name="wfHost" DockPanel.Dock="Left" SizeChanged="Window1_SizeChanged" FontSize="20" />
      </DockPanel>
    </Window>
    
  3. 在代码编辑器中打开 Window1.xaml.cs。

  4. 在该文件顶部导入以下命名空间。

    using System.Drawing;
    using System.Drawing.Drawing2D;
    using System.Windows.Forms;
    using System.Windows.Forms.Integration;
    
    Imports System.Drawing
    Imports System.Drawing.Drawing2D
    Imports System.Windows.Forms
    Imports System.Windows.Forms.Integration
    

定义新的属性映射

WindowsFormsHost 元素提供了若干默认的属性映射。 在 WindowsFormsHost 元素的 PropertyMap 上调用 Add 方法添加新的属性映射。

定义新的属性映射

  • 将以下代码复制到 Window1 类的定义中。

    // The AddClipMapping method adds a custom
    // mapping for the Clip property.
    private void AddClipMapping()
    {
        wfHost.PropertyMap.Add(
            "Clip",
            new PropertyTranslator(OnClipChange));
    }
    
    // The OnClipChange method assigns an elliptical clipping
    // region to the hosted control's Region property.
    private void OnClipChange(object h, String propertyName, object value)
    {
        WindowsFormsHost host = h as WindowsFormsHost;
        System.Windows.Forms.CheckBox cb = host.Child as System.Windows.Forms.CheckBox;
    
        if (cb != null)
        {
            cb.Region = this.CreateClipRegion();
        }
    }
    
    // The Window1_SizeChanged method handles the window's
    // SizeChanged event. It calls the OnClipChange method explicitly
    // to assign a new clipping region to the hosted control.
    private void Window1_SizeChanged(object sender, SizeChangedEventArgs e)
    {
        this.OnClipChange(wfHost, "Clip", null);
    }
    
    // The CreateClipRegion method creates a Region from an
    // elliptical GraphicsPath.
    private Region CreateClipRegion()
    {
        GraphicsPath path = new GraphicsPath();
    
        path.StartFigure();
    
        path.AddEllipse(new System.Drawing.Rectangle(
            0,
            0,
            (int)wfHost.ActualWidth,
            (int)wfHost.ActualHeight ) );
    
        path.CloseFigure();
    
        return( new Region(path) );
    }
    
    ' The AddClipMapping method adds a custom mapping 
    ' for the Clip property.
    Private Sub AddClipMapping()
    
        wfHost.PropertyMap.Add( _
            "Clip", _
            New PropertyTranslator(AddressOf OnClipChange))
    
    End Sub
    
    ' The OnClipChange method assigns an elliptical clipping 
    ' region to the hosted control's Region property.
    Private Sub OnClipChange( _
    ByVal h As Object, _
    ByVal propertyName As String, _
    ByVal value As Object)
    
        Dim host As WindowsFormsHost = h
    
        Dim cb As System.Windows.Forms.CheckBox = host.Child
    
        If cb IsNot Nothing Then
            cb.Region = Me.CreateClipRegion()
        End If
    
    End Sub
    
    ' The Window1_SizeChanged method handles the window's 
    ' SizeChanged event. It calls the OnClipChange method explicitly 
    ' to assign a new clipping region to the hosted control.
    Private Sub Window1_SizeChanged( _
    ByVal sender As Object, _
    ByVal e As SizeChangedEventArgs)
    
        Me.OnClipChange(wfHost, "Clip", Nothing)
    
    End Sub
    
    ' The CreateClipRegion method creates a Region from an
    ' elliptical GraphicsPath.
    Private Function CreateClipRegion() As [Region] 
        Dim path As New GraphicsPath()
        
        path.StartFigure()
        
        path.AddEllipse(New System.Drawing.Rectangle( _
            0, _
            0, _
            wfHost.ActualWidth, _
            wfHost.ActualHeight))
        
        path.CloseFigure()
        
        Return New [Region](path)
    
    End Function
    

    AddClipMapping 方法将为 Clip 属性添加新映射。

    OnClipChange 方法将 Clip 属性转换为 Windows FormsRegion 属性。

    Window1_SizeChanged 方法处理窗口的 SizeChanged 事件并调整剪切区域的大小以适应应用程序窗口。

删除默认属性映射

WindowsFormsHost 元素的 PropertyMap 上调用 Remove 方法删除默认属性映射。

删除默认属性映射

  • 将以下代码复制到 Window1 类的定义中。

    // The RemoveCursorMapping method deletes the default
    // mapping for the Cursor property.
    private void RemoveCursorMapping()
    {
        wfHost.PropertyMap.Remove("Cursor");
    }
    
    ' The RemoveCursorMapping method deletes the default
    ' mapping for the Cursor property.
    Private Sub RemoveCursorMapping()
        wfHost.PropertyMap.Remove("Cursor")
    End Sub
    

    RemoveCursorMapping 方法删除 Cursor 属性的默认映射。

替换默认属性映射

通过删除默认映射并在 WindowsFormsHost 元素的 PropertyMap 上调用 Add 方法可以替换默认属性映射。

替换默认属性映射

  • 将以下代码复制到 Window1 类的定义中。

    // The ReplaceFlowDirectionMapping method replaces the
    // default mapping for the FlowDirection property.
    private void ReplaceFlowDirectionMapping()
    {
        wfHost.PropertyMap.Remove("FlowDirection");
    
        wfHost.PropertyMap.Add(
            "FlowDirection",
            new PropertyTranslator(OnFlowDirectionChange));
    }
    
    // The OnFlowDirectionChange method translates a
    // Windows Presentation Foundation FlowDirection value
    // to a Windows Forms RightToLeft value and assigns
    // the result to the hosted control's RightToLeft property.
    private void OnFlowDirectionChange(object h, String propertyName, object value)
    {
        WindowsFormsHost host = h as WindowsFormsHost;
        System.Windows.FlowDirection fd = (System.Windows.FlowDirection)value;
        System.Windows.Forms.CheckBox cb = host.Child as System.Windows.Forms.CheckBox;
    
        cb.RightToLeft = (fd == System.Windows.FlowDirection.RightToLeft ) ?
            RightToLeft.Yes : RightToLeft.No;
    }
    
    // The cb_CheckedChanged method handles the hosted control's
    // CheckedChanged event. If the Checked property is true,
    // the flow direction is set to RightToLeft, otherwise it is
    // set to LeftToRight.
    private void cb_CheckedChanged(object sender, EventArgs e)
    {
        System.Windows.Forms.CheckBox cb = sender as System.Windows.Forms.CheckBox;
    
        wfHost.FlowDirection = ( cb.CheckState == CheckState.Checked ) ?
                System.Windows.FlowDirection.RightToLeft :
                System.Windows.FlowDirection.LeftToRight;
    }
    
    ' The ReplaceFlowDirectionMapping method replaces the
    ' default mapping for the FlowDirection property.
    Private Sub ReplaceFlowDirectionMapping()
    
        wfHost.PropertyMap.Remove("FlowDirection")
    
        wfHost.PropertyMap.Add( _
            "FlowDirection", _
            New PropertyTranslator(AddressOf OnFlowDirectionChange))
    End Sub
    
    
    ' The OnFlowDirectionChange method translates a 
    ' Windows Presentation Foundation FlowDirection value 
    ' to a Windows Forms RightToLeft value and assigns
    ' the result to the hosted control's RightToLeft property.
    Private Sub OnFlowDirectionChange( _
    ByVal h As Object, _
    ByVal propertyName As String, _
    ByVal value As Object)
    
        Dim host As WindowsFormsHost = h
    
        Dim fd As System.Windows.FlowDirection = _
            CType(value, System.Windows.FlowDirection)
    
        Dim cb As System.Windows.Forms.CheckBox = host.Child
    
        cb.RightToLeft = IIf(fd = System.Windows.FlowDirection.RightToLeft, _
            RightToLeft.Yes, _
            RightToLeft.No)
    
    End Sub
    
    
    ' The cb_CheckedChanged method handles the hosted control's
    ' CheckedChanged event. If the Checked property is true,
    ' the flow direction is set to RightToLeft, otherwise it is
    ' set to LeftToRight.
    Private Sub cb_CheckedChanged( _
    ByVal sender As Object, _
    ByVal e As EventArgs)
    
        Dim cb As System.Windows.Forms.CheckBox = sender
    
        wfHost.FlowDirection = IIf(cb.CheckState = CheckState.Checked, _
        System.Windows.FlowDirection.RightToLeft, _
        System.Windows.FlowDirection.LeftToRight)
    
    End Sub
    

    ReplaceFlowDirectionMapping 方法替换 FlowDirection 属性的默认映射。

    OnFlowDirectionChange 方法将 FlowDirection 属性转换为 Windows FormsRightToLeft 属性。

    cb_CheckedChanged 方法处理 CheckBox 控件上的 CheckedChanged 事件。 它根据 CheckState 属性的值分配 FlowDirection 属性

扩展默认属性映射

可以使用默认属性映射,并使用自己的映射对其进行扩展。

扩展默认属性映射

  • 将以下代码复制到 Window1 类的定义中。

    // The ExtendBackgroundMapping method adds a property
    // translator if a mapping already exists.
    private void ExtendBackgroundMapping()
    {
        if (wfHost.PropertyMap["Background"] != null)
        {
            wfHost.PropertyMap["Background"] += new PropertyTranslator(OnBackgroundChange);
        }
    }
    
    // The OnBackgroundChange method assigns a specific image
    // to the hosted control's BackgroundImage property.
    private void OnBackgroundChange(object h, String propertyName, object value)
    {
        WindowsFormsHost host = h as WindowsFormsHost;
        System.Windows.Forms.CheckBox cb = host.Child as System.Windows.Forms.CheckBox;
        ImageBrush b = value as ImageBrush;
    
        if (b != null)
        {
            cb.BackgroundImage = new System.Drawing.Bitmap(@"C:\WINDOWS\Santa Fe Stucco.bmp");
        }
    }
    
    ' The ExtendBackgroundMapping method adds a property
    ' translator if a mapping already exists.
    Private Sub ExtendBackgroundMapping() 
        If wfHost.PropertyMap("Background") IsNot Nothing Then
    
            wfHost.PropertyMap("Background") = PropertyTranslator.Combine( _
            wfHost.PropertyMap("Background"), _
            PropertyTranslator.CreateDelegate( _
                GetType(PropertyTranslator), _
                Me, _
                "OnBackgroundChange"))
        End If
    
    End Sub
    
    
    ' The OnBackgroundChange method assigns a specific image 
    ' to the hosted control's BackgroundImage property.
    Private Sub OnBackgroundChange(ByVal h As Object, ByVal propertyName As String, ByVal value As Object) 
        Dim host As WindowsFormsHost = h 
        Dim cb As System.Windows.Forms.CheckBox = host.Child 
        Dim b As ImageBrush = value 
        
        If Not (b Is Nothing) Then
            cb.BackgroundImage = New System.Drawing.Bitmap("C:\WINDOWS\Santa Fe Stucco.bmp")
        End If
    
    End Sub
    

    ExtendBackgroundMapping 方法将自定义属性转换器添加到现有的 Background 属性映射。

    OnBackgroundChange 方法将特定图像分配给托管控件的 BackgroundImage 属性。 在应用默认属性映射后会调用 OnBackgroundChange 方法。

初始化属性映射

通过调用 Loaded 事件处理程序中前面所述的方法来设置属性映射。

初始化属性映射

  1. 将以下代码复制到 Window1 类的定义中。

    // The WindowLoaded method handles the Loaded event.
    // It enables Windows Forms visual styles, creates
    // a Windows Forms checkbox control, and assigns the
    // control as the child of the WindowsFormsHost element.
    // This method also modifies property mappings on the
    // WindowsFormsHost element.
    private void WindowLoaded(object sender, RoutedEventArgs e)
    {
        System.Windows.Forms.Application.EnableVisualStyles();
    
        // Create a Windows Forms checkbox control and assign
        // it as the WindowsFormsHost element's child.
        System.Windows.Forms.CheckBox cb = new System.Windows.Forms.CheckBox();
        cb.Text = "Windows Forms checkbox";
        cb.Dock = DockStyle.Fill;
        cb.TextAlign = ContentAlignment.MiddleCenter;
        cb.CheckedChanged += new EventHandler(cb_CheckedChanged);
        wfHost.Child = cb;
    
        // Replace the default mapping for the FlowDirection property.
        this.ReplaceFlowDirectionMapping();
    
        // Remove the mapping for the Cursor property.
        this.RemoveCursorMapping();
    
        // Add the mapping for the Clip property.
        this.AddClipMapping();
    
        // Add another mapping for the Background property.
        this.ExtendBackgroundMapping();
    
        // Cause the OnFlowDirectionChange delegate to be called.
        wfHost.FlowDirection = System.Windows.FlowDirection.LeftToRight;
    
        // Cause the OnClipChange delegate to be called.
        wfHost.Clip = new RectangleGeometry();
    
        // Cause the OnBackgroundChange delegate to be called.
        wfHost.Background = new ImageBrush();
    }
    
    ' The WindowLoaded method handles the Loaded event.
    ' It enables Windows Forms visual styles, creates 
    ' a Windows Forms checkbox control, and assigns the
    ' control as the child of the WindowsFormsHost element. 
    ' This method also modifies property mappings on the 
    ' WindowsFormsHost element.
    Private Sub WindowLoaded( _
    ByVal sender As Object, _
    ByVal e As RoutedEventArgs)
    
        System.Windows.Forms.Application.EnableVisualStyles()
    
        ' Create a Windows Forms checkbox control and assign 
        ' it as the WindowsFormsHost element's child.
        Dim cb As New System.Windows.Forms.CheckBox()
        cb.Text = "Windows Forms checkbox"
        cb.Dock = DockStyle.Fill
        cb.TextAlign = ContentAlignment.MiddleCenter
        AddHandler cb.CheckedChanged, AddressOf cb_CheckedChanged
        wfHost.Child = cb
    
        ' Replace the default mapping for the FlowDirection property.
        Me.ReplaceFlowDirectionMapping()
    
        ' Remove the mapping for the Cursor property.
        Me.RemoveCursorMapping()
    
        ' Add the mapping for the Clip property.
        Me.AddClipMapping()
    
        ' Add another mapping for the Background property.
        Me.ExtendBackgroundMapping()
    
        ' Cause the OnFlowDirectionChange delegate to be called.
        wfHost.FlowDirection = System.Windows.FlowDirection.LeftToRight
    
        ' Cause the OnClipChange delegate to be called.
        wfHost.Clip = New RectangleGeometry()
    
        ' Cause the OnBackgroundChange delegate to be called.
        wfHost.Background = New ImageBrush()
    
    End Sub
    

    WindowLoaded 方法处理 Loaded 事件并执行以下初始化。

    • 创建 Windows FormsCheckBox 控件。

    • 调用先前在演练中定义的方法来设置属性映射。

    • 将初始值分配给映射的属性。

  2. 按 F5 生成并运行应用程序。 单击复选框可查看 FlowDirection 映射的效果。 单击复选框时,布局会反转其左右方向。

另请参阅