创建透明窗体

     透明窗体，顾名思义，就是窗体是透明的，透过窗体可以看到窗体下面的东西。实现透明窗体的原理也很简单：首先得到主窗口的矩形区域，再得到客户区的矩形区域，然后用CombineRgn函数，使用异或操作，将重叠部分去除，再使用SetWindowRgn函数设置窗体区域，就行了。下面的例子实现了该功能。>>步骤1----建立新工程。>>步骤2----编写如下代码：Private Declare Function GetWindowRect Lib "user32" (ByVal hWnd _    As Long, lpRECT As RECT) As LongPrivate Declare Function GetClientRect Lib "user32" (ByVal hWnd _    As Long, lpRECT As RECT) As LongPrivate Declare Function CombineRgn Lib "gdi32" (ByVal hDestRgn _    As Long, ByVal hSrcRgn1 As Long, ByVal hSrcRgn2 As Long, _    ByVal nCombineMode As Long) As LongPrivate Declare Function CreateRectRgn Lib "gdi32" (ByVal X1 As _    Long, ByVal Y1 As Long, ByVal X2 As Long, ByVal Y2 As Long) _    As LongPrivate Declare Function ScreenToClient Lib "user32" (ByVal hWnd _    As Long, lpPoint As POINTAPI) As LongPrivate Declare Function SetWindowRgn Lib "user32" (ByVal hWnd As _    Long, ByVal hRgn As Long, ByVal bRedraw As Boolean) As LongConst RGN_XOR = 3Private Type POINTAPI    x As Long    Y As LongEnd TypePrivate Type RECT    Left As Long    Top As Long    Right As Long    Bottom As LongEnd TypePrivate rctClient As RECT, rctFrame As RECTPrivate hClient As Long, hFrame As LongPublic Sub MakeTransparent(frm As Form)    GetFrameClientRgn frm    SetWindowRgn frm.hWnd, hFrame, TrueEnd SubPrivate Sub GetFrameClientRgn(frm As Form)    GetWindowRect frm.hWnd, rctFrame    GetClientRect frm.hWnd, rctClient    '将窗口矩形坐标转换为屏幕坐标    Dim lpTL As POINTAPI, lpBR As POINTAPI    lpTL.x = rctFrame.Left    lpTL.Y = rctFrame.Top    lpBR.x = rctFrame.Right    lpBR.Y = rctFrame.Bottom    ScreenToClient frm.hWnd, lpTL    ScreenToClient frm.hWnd, lpBR    rctFrame.Left = lpTL.x    rctFrame.Top = lpTL.Y    rctFrame.Right = lpBR.x    rctFrame.Bottom = lpBR.Y    rctClient.Left = Abs(rctFrame.Left)    rctClient.Top = Abs(rctFrame.Top)    rctClient.Right = rctClient.Right + Abs(rctFrame.Left)    rctClient.Bottom = rctClient.Bottom + Abs(rctFrame.Top)    rctFrame.Right = rctFrame.Right + Abs(rctFrame.Left)    rctFrame.Bottom = rctFrame.Bottom + Abs(rctFrame.Top)    rctFrame.Top = 0    rctFrame.Left = 0    hClient = CreateRectRgn(rctClient.Left, rctClient.Top, _    rctClient.Right, rctClient.Bottom)    hFrame = CreateRectRgn(rctFrame.Left, rctFrame.Top, _    rctFrame.Right, rctFrame.Bottom)    CombineRgn hFrame, hClient, hFrame, RGN_XOREnd SubPrivate Sub Form_Resize()    MakeTransparent MeEnd Sub>>步骤3----编译运行，是不是看到效果了。