逐步解說：使用 ElementHost 控制項對應屬性

  • 發行項

本逐步解說說明如何使用 PropertyMap 屬性，將 Windows Forms 屬性對應至託管 WPF 元素上的對應屬性。

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，您將能夠將 Windows Forms 屬性對應至裝載元素上的對應 WPF 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. 建立名為 PropertyMappingWithElementHost 的 Windows Forms 應用程式 專案。

  2. 在 方案總管 中，新增下列 WPF 元件的參考。

    • PresentationCore

    • PresentationFramework

    • WindowsBase

    • WindowsFormsIntegration

  3. 將下列程式碼複製到程式碼檔案頂 Form1 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。 按兩下表單以新增事件的事件處理常式 Load 。

  5. 返回 Windows Forms 設計工具，並新增表單 Resize 事件的事件處理常式。 如需詳細資訊，請參閱 如何：使用設計 工具建立事件處理常式。

  6. ElementHost宣告 類別中的 Form1 欄位。

    ElementHost elemHost = null;

    Private elemHost As ElementHost = Nothing

定義新的屬性對應

控制項 ElementHost 提供數個預設屬性對應。 您可以在 控制項 PropertyMap 的 上 ElementHost 呼叫 Add 方法，以新增屬性對應。

定義新的屬性對應

  1. 將下列程式碼複製到 類別的定義 Form1 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

    方法 AddMarginMapping 會新增 Margin 屬性的新對應。

    方法會將 OnMarginChangeMargin 屬性轉譯為 WPF Margin 屬性。

  2. 將下列程式碼複製到 類別的定義 Form1 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

    方法 AddRegionMapping 會新增 Region 屬性的新對應。

    方法會將 OnRegionChangeRegion 屬性轉譯為 WPF Clip 屬性。

    方法 Form1_Resize 會處理表單的事件 Resize ，並調整裁剪區域的大小以符合裝載的專案。

移除預設屬性對應

在 控制項 PropertyMap 上 ElementHost 呼叫 Remove 方法，以移除預設屬性對應。

移除預設屬性對應

  • 將下列程式碼複製到 類別的定義 Form1 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

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

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 類別的定義 Form1 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

    方法 ExtendBackColorMapping 會將自訂屬性翻譯工具新增至現有的 BackColor 屬性對應。

    方法 OnBackColorChange 會將特定映射指派給裝載控制項的 Background 屬性。 在 OnBackColorChange 套用預設屬性對應之後，會呼叫 方法。

初始化屬性對應

  1. 將下列程式碼複製到 類別的定義 Form1 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

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

    • 建立 WPF Button 專案。

    • 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