GetForegroundWindow() 更改时是否会触发任何系统事件？

我正在开发一个应用程序，需要获取应用程序运行时处于活动状态的窗口名称，目前我每半秒执行一次对 GetForegroundwindow() 的调用，但这几乎不准确，我不想把它以 100 毫秒为间隔，我认为这很糟糕而且不准确，有没有任何系统事件可以为我做到这一点？

Thanks.

- 更新 -

你可以使用设置WindowsHookEx http://msdn.microsoft.com/en-us/library/windows/desktop/ms644990%28v=vs.85%29.aspx监视当前桌面，但这在托管代码中不起作用。相反，您必须使用设置WinEventHook http://msdn.microsoft.com/en-us/library/dd373640%28v=vs.85%29.aspx.

您曾问过如何使用设置WinEventHook http://msdn.microsoft.com/en-us/library/dd373640%28v=vs.85%29.aspxp/调用方法。这是你的答案：

首先确保此行位于代码文件的顶部：

Imports System.Runtime.InteropServices

接下来，声明调用该调用所需的所有内容：

Public Const WINEVENT_OUTOFCONTEXT = &H0  
'' Events are ASYNC

Public Const WINEVENT_SKIPOWNTHREAD = &H1  
'' Don't call back for events on installer's thread

Public Const WINEVENT_SKIPOWNPROCESS = &H2  
'' Don't call back for events on installer's process

Public Const WINEVENT_INCONTEXT = &H4  
'' Events are SYNC, this causes your dll to be injected into every process

    Public Declare Function SetWinEventHook Lib "user32.dll" _
       (eventMin As UInteger, _
        eventMax As UInteger, _
        hmodWinEventProc As IntPtr, _
        lpfnWinEventProc As IntPtr, _
        idProcess As UInteger, _
        idThread As UInteger, _
        dwflags As UInteger) As IntPtr

    Public Declare Function UnhookWinEvent Lib "user32.dll" _
        (hWinEventHook As IntPtr) As <MarshalAs(UnmanagedType.Bool)> Boolean

    Public Delegate Sub WinEventProc( _
          hWinEventHook As IntPtr, _
          [event] As UInteger, _
          hwnd As IntPtr, _
          idObject As Integer, _
          idChild As Integer, _
          dwEventThread As UInteger, _
          dwmsEventTime As UInteger)

接下来，您将一个函数和一个新变量声明为函数，并带有该函数的地址：

    Public Sub EventCallBack( _
      hWinEventHook As IntPtr, _
      [event] As UInteger, _
      hwnd As IntPtr, _
      idObject As Integer, _
      idChild As Integer, _
      dwEventThread As UInteger, _
      dwmsEventTime As UInteger)

' Some code goes here
    End Sub

    Private eventProc As New WinEventProc(AddressOf EventCallBack)
    Private hEventHook As IntPtr

最后，将它们连接在一起，并传递以下代码行来创建挂钩（0 和 255 是任意数字，将它们替换为您想要观看的最小和最大消息代码）：

hEventHook = SetWinEventHook(0, _
                             255, _
                             IntPtr.Zero, _
                             Marshal.GetFunctionPointerForDelegate(eventProc), _
                             0, _
                             0, _
                             WINEVENT_OUTOFCONTEXT)

当您的程序完成时，将以下行添加到应用程序终止事件或表单的 Dispose 或 Finalize 方法中：

        UnhookWinEvent(hEventHook)

这在我的测试应用程序上按预期运行。