公开服务器端 UI 自动化提供程序

  • 项目

注意

本文档适用于想要使用 System.Windows.Automation 命名空间中定义的托管 UI 自动化类的 .NET Framework 开发人员。 有关 UI 自动化的最新信息，请参阅 Windows 自动化 API：UI 自动化。

本主题包含演示如何公开承载在 System.Windows.Forms.Control 窗口中服务器端 UI 自动化提供程序的代码示例。

此示例重写窗口过程以捕获 WM_GETOBJECT，这是客户端应用程序请求有关窗口的信息时，UI 自动化核心服务发送的消息。

示例

/// <summary>
/// Handles WM_GETOBJECT message; others are passed to base handler.
/// </summary>
/// <param name="m">Windows message.</param>
/// <remarks>
/// This method enables UI Automation to find the control.
/// In this example, the implementation of IRawElementProvider is in the same class
/// as this method.
/// </remarks>
protected override void WndProc(ref Message m)
{
    const int WM_GETOBJECT = 0x003D;

    if ((m.Msg == WM_GETOBJECT) && ((int)(long)m.LParam ==
        AutomationInteropProvider.RootObjectId))
    {
        m.Result = AutomationInteropProvider.ReturnRawElementProvider(
                this.Handle, m.WParam, m.LParam,
                (IRawElementProviderSimple)this);
        return;
    }
    base.WndProc(ref m);
}

''' <summary>
''' Handles WM_GETOBJECT message; others are passed to base handler.
''' </summary>
''' <param name="m">Windows message.</param>
''' <remarks>
''' This method enables UI Automation to find the control.
''' In this example, the implementation of IRawElementProvider is in the same class
''' as this method.
''' </remarks>
Protected Overrides Sub WndProc(ByRef m As Message)
    Const WM_GETOBJECT As Integer = &H3D

    If m.Msg = WM_GETOBJECT AndAlso CInt(CLng(m.LParam)) = AutomationInteropProvider.RootObjectId Then
        m.Result = AutomationInteropProvider.ReturnRawElementProvider(Me.Handle, m.WParam, m.LParam, DirectCast(Me, IRawElementProviderSimple))
        Return
    End If
    MyBase.WndProc(m)

End Sub

请参阅