关于前台窗口的解决方法

forowhl · 发表于 2011-8-19 22:01:00

最近做了一个小程序，要从自己编写的小程序切换到窗口，当然用alt+tab也可以切换，现在想自动切换，以前用vb的时候知道怎么做，现在用vb.net了。到网上搜了好久也没有看到好方法，呵呵，就把以前的vb代码升级了一下，大家看着用。。有好方法的告诉我一声。。
代码示例：要求新建一个窗体应用程序项目，在form1里面添加一个Button1按钮，复制下面代码，运行点击button1，切换到autocad窗口，在cad窗体上面选择一点，然后返回到form窗口。

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Public Class Form1
    Private Declare Function GetWindowThreadProcessId Lib "user32" (ByVal hWnd As Integer, ByRef lpdwProcessId As Integer) As Integer
    Private Declare Function AttachThreadInput Lib "user32" (ByVal idAttach As Integer, ByVal idAttachTo As Integer, ByVal fAttach As Integer) As Integer
    Private Declare Function GetForegroundWindow Lib "user32" () As Integer
    Private Declare Function SetForegroundWindow Lib "user32" (ByVal hWnd As Integer) As Integer
    Private Declare Function IsIconic Lib "user32" (ByVal hWnd As Integer) As Integer
    Private Declare Function ShowWindow Lib "user32" (ByVal hWnd As Integer, ByVal nCmdShow As Integer) As Integer
    Private Const SW_SHOW As Short = 5
    Private Const SW_RESTORE As Short = 9
    Public Function ForceForegroundWindow(ByVal hWnd As Integer) As Boolean
        Dim ThreadID1 As Integer ' 线程ID
        Dim ThreadID2 As Integer ' 线程ID
        Dim nRet As Integer
        '  如果指定的窗体已经在前台，不做任何操作
        If hWnd = GetForegroundWindow() Then
            ForceForegroundWindow = True
        Else
            ' 首先获得指定窗体相关的线程和当前前台窗口所在的线程
            ThreadID1 = GetWindowThreadProcessId(GetForegroundWindow, 0)
            ThreadID2 = GetWindowThreadProcessId(hWnd, 0)
            ' 通过共享输入状态，两个线程分享当前窗口
            If ThreadID1  ThreadID2 Then
                Call AttachThreadInput(ThreadID1, ThreadID2, True)
                nRet = SetForegroundWindow(hWnd)
                Call AttachThreadInput(ThreadID1, ThreadID2, False)
            Else
                nRet = SetForegroundWindow(hWnd)
            End If
            '恢复和重画
            If IsIconic(hWnd) Then
                Call ShowWindow(hWnd, SW_RESTORE)
            Else
                Call ShowWindow(hWnd, SW_SHOW)
            End If
            '  精确地返回函数执行结果
            ForceForegroundWindow = CBool(nRet)
        End If
    End Function
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim myAcadApp As Object
        myAcadApp = GetObject(, "Autocad.Application") '获得autocad程序
        ' myAcadApp = GetObject(, "Excel.Application")'如果想切换到excel窗口，用这句代码
        ForceForegroundWindow(myAcadApp.hWnd)
        myAcadApp.ActiveDocument.Utility.GetPoint(, "选择一点：")
        ForceForegroundWindow(Me.Handle)
    End Sub
End Class