逐步解說：使用 ElementHost 控制項對應屬性

本操作指引將向您展示如何使用此PropertyMap屬性，將 Windows Forms 屬性對應到託管的WPF項目上的相應屬性。

這個逐步解說中所述的工作包括：

• 建立專案。

• 定義新的屬性對應。

• 移除預設屬性對應。

• 擴充預設屬性對應。

完成時，您將可以用 Windows Forms 屬性對應到託管的WPF項目上的相應屬性。

必要條件

您需要下列元件才能完成這個逐步解說：

• Visual Studio 2017

建立專案

建立專案

1. 建立一個 Windows Forms 應用程式 專案名字PropertyMappingWithElementHost。

2. 在[方案總管]中，新增對下列WPF組件的引用。

   • PresentationCore

   • PresentationFramework

   • WindowsBase

   • WindowsFormsIntegration

3. 將下列Form1代碼複製到程式碼的檔案頂端。

   using System.Windows;
   using System.Windows.Media;
   using System.Windows.Media.Imaging;
   using System.Windows.Forms.Integration;
   

   Imports System.Windows
   Imports System.Windows.Media
   Imports System.Windows.Media.Imaging
   Imports System.Windows.Forms.Integration
   

4. 在 Windows Form 設計工具中開啟 Form1。 點選兩下該表單以新增該Load事件的事件處理程式。

5. 返回 Windows Form 設計工具，並新增表單Resize事件的事件處理程式。 若需更多資訊，請參閱如何：使用設計工具以建立事件處理程式。

6. 在本Form1類別中宣告ElementHost這個欄位。

   ElementHost elemHost = null;
   

   Private elemHost As ElementHost = Nothing
   

定義出新的屬性對應

該ElementHost控件提供了一些預設的屬性對應。 您可以透過在ElementHost控件的屬性PropertyMap上呼叫 Add該方法，以添加一個新的屬性對應。

為了定義出新的屬性對應

1. 將下列程式碼複製到該Form1類別的定義中。

   // The AddMarginMapping method adds a new property mapping
   // for the Margin property.
   private void AddMarginMapping()
   {
       elemHost.PropertyMap.Add(
           "Margin",
           new PropertyTranslator(OnMarginChange));
   }
   
   // The OnMarginChange method implements the mapping
   // from the Windows Forms Margin property to the
   // Windows Presentation Foundation Margin property.
   //
   // The provided Padding value is used to construct
   // a Thickness value for the hosted element's Margin
   // property.
   private void OnMarginChange(object h, String propertyName, object value)
   {
       ElementHost host = h as ElementHost;
       Padding p = (Padding)value;
       System.Windows.Controls.Button wpfButton =
           host.Child as System.Windows.Controls.Button;
   
       Thickness t = new Thickness(p.Left, p.Top, p.Right, p.Bottom );
   
       wpfButton.Margin = t;
   }
   

   ' The AddMarginMapping method adds a new property mapping
   ' for the Margin property.
   Private Sub AddMarginMapping()
   
       elemHost.PropertyMap.Add( _
           "Margin", _
           New PropertyTranslator(AddressOf OnMarginChange))
   
   End Sub
   
   
   ' The OnMarginChange method implements the mapping 
   ' from the Windows Forms Margin property to the
   ' Windows Presentation Foundation Margin property.
   '
   ' The provided Padding value is used to construct 
   ' a Thickness value for the hosted element's Margin
   ' property.
   Private Sub OnMarginChange( _
   ByVal h As Object, _
   ByVal propertyName As String, _
   ByVal value As Object)
   
       Dim host As ElementHost = h
       Dim p As Padding = CType(value, Padding)
       Dim wpfButton As System.Windows.Controls.Button = host.Child
   
   
       Dim t As New Thickness(p.Left, p.Top, p.Right, p.Bottom)
   
       wpfButton.Margin = t
   
   End Sub
   

   本AddMarginMapping方法會增加一個Margin屬性的新對應。

   本OnMarginChange方法會將Margin屬性轉譯為WPFMargin的屬性。

2. 將下列程式碼複製到該Form1類別的定義中。

   // The AddRegionMapping method assigns a custom
   // mapping for the Region property.
   private void AddRegionMapping()
   {
       elemHost.PropertyMap.Add(
           "Region",
           new PropertyTranslator(OnRegionChange));
   }
   
   // The OnRegionChange method assigns an EllipseGeometry to
   // the hosted element's Clip property.
   private void OnRegionChange(
       object h,
       String propertyName,
       object value)
   {
       ElementHost host = h as ElementHost;
       System.Windows.Controls.Button wpfButton =
           host.Child as System.Windows.Controls.Button;
   
       wpfButton.Clip = new EllipseGeometry(new Rect(
           0,
           0,
           wpfButton.ActualWidth,
           wpfButton.ActualHeight));
   }
   
   // The Form1_Resize method handles the form's Resize event.
   // It calls the OnRegionChange method explicitly to
   // assign a new clipping geometry to the hosted element.
   private void Form1_Resize(object sender, EventArgs e)
   {
       this.OnRegionChange(elemHost, "Region", null);
   }
   

   ' The AddRegionMapping method assigns a custom 
   ' mapping for the Region property.
   Private Sub AddRegionMapping()
   
       elemHost.PropertyMap.Add( _
           "Region", _
           New PropertyTranslator(AddressOf OnRegionChange))
   
   End Sub
   
   
   ' The OnRegionChange method assigns an EllipseGeometry to
   ' the hosted element's Clip property.
   Private Sub OnRegionChange( _
   ByVal h As Object, _
   ByVal propertyName As String, _
   ByVal value As Object)
   
       Dim host As ElementHost = h
   
       Dim wpfButton As System.Windows.Controls.Button = host.Child
   
       wpfButton.Clip = New EllipseGeometry(New Rect( _
           0, _
           0, _
           wpfButton.ActualWidth, _
           wpfButton.ActualHeight))
   
   End Sub
   
   
   ' The Form1_Resize method handles the form's Resize event.
   ' It calls the OnRegionChange method explicitly to 
   ' assign a new clipping geometry to the hosted element.
   Private Sub Form1_Resize( _
   ByVal sender As Object, _
   ByVal e As EventArgs) Handles MyBase.Resize
   
       If elemHost IsNot Nothing Then
           Me.OnRegionChange(elemHost, "Region", Nothing)
       End If
   
   End Sub
   

   本AddRegionMapping方法會增加一個Region屬性的新對應。

   本OnRegionChange方法會將Region屬性轉譯為WPFClip的屬性。

   本Form1_Resize方法會處理表單的Resize事件，並調整成剪輯區域的大小以符合託管的項目。

移除預設屬性對應

您可以透過在ElementHost控件的屬性PropertyMap上呼叫Remove該方法，以移除一個預設屬性對應。

移除預設屬性對應

• 將下列程式碼複製到該Form1類別的定義中。

  // The RemoveCursorMapping method deletes the default
  // mapping for the Cursor property.
  private void RemoveCursorMapping()
  {
      elemHost.PropertyMap.Remove("Cursor");
  }
  

  ' The RemoveCursorMapping method deletes the default
  ' mapping for the Cursor property.
  Private Sub RemoveCursorMapping()
      elemHost.PropertyMap.Remove("Cursor")
  End Sub
  

  本RemoveCursorMapping方法會刪除該Cursor屬性的預設對應。

擴充預設屬性對應

您可以使用預設屬性對應，也可以使用自己的對應來進行擴充。

擴充預設屬性對應

• 將下列程式碼複製到該Form1類別的定義中。

  // The ExtendBackColorMapping method adds a property
  // translator if a mapping already exists.
  private void ExtendBackColorMapping()
  {
      if (elemHost.PropertyMap["BackColor"] != null)
      {
          elemHost.PropertyMap["BackColor"] +=
              new PropertyTranslator(OnBackColorChange);
      }
  }
  
  // The OnBackColorChange method assigns a specific image
  // to the hosted element's Background property.
  private void OnBackColorChange(object h, String propertyName, object value)
  {
      ElementHost host = h as ElementHost;
      System.Windows.Controls.Button wpfButton =
          host.Child as System.Windows.Controls.Button;
  
      ImageBrush b = new ImageBrush(new BitmapImage(
          new Uri(@"file:///C:\WINDOWS\Santa Fe Stucco.bmp")));
      wpfButton.Background = b;
  }
  

  ' The ExtendBackColorMapping method adds a property
  ' translator if a mapping already exists.
  Private Sub ExtendBackColorMapping()
  
      If elemHost.PropertyMap("BackColor") IsNot Nothing Then
  
          elemHost.PropertyMap("BackColor") = PropertyTranslator.Combine( _
              elemHost.PropertyMap("BackColor"), _
              PropertyTranslator.CreateDelegate( _
              GetType(PropertyTranslator), _
              Me, _
              "OnBackColorChange"))
      End If
  
  End Sub
  
  
  ' The OnBackColorChange method assigns a specific image 
  ' to the hosted element's Background property.
  Private Sub OnBackColorChange( _
  ByVal h As Object, _
  ByVal propertyName As String, _
  ByVal value As Object)
  
      Dim host As ElementHost = h
      Dim wpfButton As System.Windows.Controls.Button = host.Child
      Dim b As New ImageBrush(New BitmapImage( _
          New Uri("file:///C:\WINDOWS\Santa Fe Stucco.bmp")))
      wpfButton.Background = b
  
  End Sub
  

  本ExtendBackColorMapping方法會將一個自定義屬性翻譯工具新增到現有的BackColor屬性對應中。

  本OnBackColorChange方法會將一個特定數位影像指派給主控控件的Background屬性上。 在套用預設屬性對應之後，會呼叫此OnBackColorChange方法。

初始化您的屬性對應

1. 將下列程式碼複製到該Form1類別的定義中。

   private void Form1_Load(object sender, EventArgs e)
   {
       // Create the ElementHost control.
       elemHost = new ElementHost();
       elemHost.Dock = DockStyle.Fill;
       this.Controls.Add(elemHost);
   
       // Create a Windows Presentation Foundation Button element
       // and assign it as the ElementHost control's child.
       System.Windows.Controls.Button wpfButton = new System.Windows.Controls.Button();
       wpfButton.Content = "Windows Presentation Foundation Button";
       elemHost.Child = wpfButton;
   
       // Map the Margin property.
       this.AddMarginMapping();
   
       // Remove the mapping for the Cursor property.
       this.RemoveCursorMapping();
   
       // Add a mapping for the Region property.
       this.AddRegionMapping();
   
       // Add another mapping for the BackColor property.
       this.ExtendBackColorMapping();
   
       // Cause the OnMarginChange delegate to be called.
       elemHost.Margin = new Padding(23, 23, 23, 23);
   
       // Cause the OnRegionChange delegate to be called.
       elemHost.Region = new Region();
   
       // Cause the OnBackColorChange delegate to be called.
       elemHost.BackColor = System.Drawing.Color.AliceBlue;
   }
   

   Private Sub Form1_Load( _
   ByVal sender As Object, _
   ByVal e As EventArgs) Handles MyBase.Load
   
       ' Create the ElementHost control.
       elemHost = New ElementHost()
       elemHost.Dock = DockStyle.Fill
       Me.Controls.Add(elemHost)
   
       ' Create a Windows Presentation Foundation Button element 
       ' and assign it as the ElementHost control's child. 
       Dim wpfButton As New System.Windows.Controls.Button()
       wpfButton.Content = "Windows Presentation Foundation Button"
       elemHost.Child = wpfButton
   
       ' Map the Margin property.
       Me.AddMarginMapping()
   
       ' Remove the mapping for the Cursor property.
       Me.RemoveCursorMapping()
   
       ' Add a mapping for the Region property.
       Me.AddRegionMapping()
   
       ' Add another mapping for the BackColor property.
       Me.ExtendBackColorMapping()
   
       ' Cause the OnMarginChange delegate to be called.
       elemHost.Margin = New Padding(23, 23, 23, 23)
   
       ' Cause the OnRegionChange delegate to be called.
       elemHost.Region = New [Region]()
   
       ' Cause the OnBackColorChange delegate to be called.
       elemHost.BackColor = System.Drawing.Color.AliceBlue
   
   End Sub
   

   本Form1_Load方法會處理該Load事件，並執行下列初始化作業。

   • 建立一個WPF的Button項目。

   • 呼叫您稍早在本逐步解說中所定義的方法來設定屬性對應。

   • 將初始值指派給對應的屬性。

2. 按 F5 以建置並執行應用程式。

另請參閱

• ElementHost.PropertyMap
• WindowsFormsHost.PropertyMap
• WindowsFormsHost
• Windows Forms 和 WPF 屬性對應
• 在 Visual Studio 中設計 XAML
• 逐步解說：在 Windows Form 中裝載 WPF 複合控制項