演练：使用 WindowsFormsHost 元素映射属性

项目
05/04/2023

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

创建一个名为 PropertyMappingWithWfhSample 的 WPF 应用项目。
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。
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

在 WPF 设计器中打开 Window1.xaml。

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>

在代码编辑器中打开 Window1.xaml.cs。

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

在 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

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。

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。

通过

演练：使用 WindowsFormsHost 元素映射属性

先决条件

创建并设置项目

定义应用程序布局

定义应用程序布局

定义新的属性映射

定义新的属性映射

删除默认属性映射

删除默认属性映射

替换默认属性映射

替换默认属性映射

扩展默认属性映射

扩展默认属性映射

初始化属性映射

初始化属性映射

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