窗体代码:

Option Explicit

Private Sub Check1_Click()
    Dim t As Long
    If Me.Check1.Value = 1 Then
        t = HWND_TOPMOST
    Else
        t = HWND_NOTOPMOST
    End If
    Call SetWindowPos(Me.hwnd, t, Me.Left, Me.Top, Me.Width, Me.Height, 3)
End Sub

Private Sub cmdEnumAll_Click()
    Me.lvDetail.ListItems.Clear
    Call EnumWindows(AddressOf EnumWindowProc, &H0&)
End Sub

Private Sub cmdEnumChild_Click()
    If Me.lvDetail.SelectedItem Is Nothing Then
        MsgBox "无子窗体可枚举", vbOKOnly + vbInformation, "提示"
        Exit Sub
    End If
    Dim lParam As Long
    lParam = 0
    Call EnumChildWindows(GetKey(Me.lvDetail.SelectedItem.Key), AddressOf EnumChildWindowProc, lParam)
    If lParam = 0 Then
        MsgBox "当前窗口无子窗口!", vbOKOnly + vbInformation, "提示"
    End If
End Sub

Private Sub cmdEnumParent_Click()
    If Me.lvDetail.SelectedItem Is Nothing Then
        MsgBox "无上一级窗体可枚举", vbOKOnly + vbInformation, "提示"
        Exit Sub
    End If
    If GetParent(GetKey(Me.lvDetail.SelectedItem.Key)) = 0 Then
        MsgBox "当前窗体是顶级窗口!", vbOKOnly + vbInformation, "提示"
        Exit Sub
    Else
        If GetParent(GetParent(GetKey(Me.lvDetail.SelectedItem.Key))) = 0 Then
            Call cmdEnumAll_Click
        Else
            Dim lParam As Long
            lParam = 0
            Call EnumChildWindows(GetParent(GetParent(GetKey(Me.lvDetail.SelectedItem.Key))), AddressOf EnumChildWindowProc, lParam)
        End If
    End If
End Sub

Public Sub cmdGetMouseWindow_Click()
    idHotKey = 1
    If Timer1.Enabled = False Then
        Me.Timer1.Interval = 1
        Me.Timer1.Enabled = True
        Me.cmdGetMouseWindow.Caption = "停止鼠标获取(CTRL+S)"
        Modifiers = MOD_CONTROL
        idHotKey = 1
        If RegisterHotKey(Me.hwnd, idHotKey, Modifiers, vbKeyS) = False Then
            MsgBox "注册Ctrl+S热键失败", vbOKOnly + vbYesNo, "提示"
        End If
        preWinProc = SetWindowLong(Me.hwnd, GWL_WNDPROC, AddressOf wndProc)
    Else
        Me.Timer1.Enabled = False
        Me.cmdGetMouseWindow.Caption = "鼠标获取"
        SetWindowLong Me.hwnd, GWL_WNDPROC, preWinProc
        If UnregisterHotKey(Me.hwnd, idHotKey) = False Then
            MsgBox "取消热键Ctrl+S失败", vbOKOnly + vbInformation, "提示"
        End If
    End If
End Sub

Private Sub cmdSendMessage_Click()
    On Error GoTo errHandle:
    Call SendMessage(CLng(Me.txthWnd.Text), CLng(Me.txtMsg.Text), CLng(Me.txtWparam.Text), CLng(Me.txtlParam.Text))
    Exit Sub
errHandle:
    MsgBox Err.Description

End Sub

Private Sub Form_Load()
    Me.Check1.Value = 0
    Me.Check1.Value = 1
End Sub

Private Sub Timer1_Timer()
    Dim PT As POINTAPI
    Dim strTitle As String
    Dim strClassName As String
    Dim myItem As ListItem
    Call GetCursorPos(PT)
    Dim hwnd As Long
    hwnd = WindowFromPoint(PT.x, PT.y)
    Call GetTitleClass(hwnd, strTitle, strClassName)
    Me.lvDetail.ListItems.Clear
    Set myItem = Me.lvDetail.ListItems.Add(, MakeKey(CStr(hwnd)))
    myItem.Text = strTitle
    myItem.SubItems(1) = strClassName
    myItem.SubItems(2) = hwnd
End Sub
'模块代码:

Option Explicit

Public Const LVIF_INDENT As Long = &H10
Public Const LVIF_TEXT As Long = &H1
Public Const LVM_FIRST As Long = &H1000
Public Const LVM_SETITEM As Long = (LVM_FIRST + 6)
Public Const HWND_TOPMOST = -1
Public Const HWND_NOTOPMOST = -2
Public Const SWP_SHOWWINDOW = &H40
Public Const WM_HOTKEY = &H312
Public Const MOD_ALT = &H1
Public Const MOD_CONTROL = &H2
Public Const MOD_SHIFT = &H4
Public Const GWL_WNDPROC = (-4)

Public preWinProc As Long
Public Modifiers As Long, uVirtKey As Long, idHotKey As Long

Public Type POINTAPI
        x As Long
        y As Long
End Type

Public Type LVITEM
   mask As Long
   iItem As Long
   iSubItem As Long
   state As Long
   stateMask As Long
   pszText As String
   cchTextMax As Long
   iImage As Long
   lParam As Long
   iIndent As Long
End Type

Public Declare Function WindowFromPoint Lib "user32" (ByVal xPoint As Long, ByVal yPoint As Long) As Long
Public Declare Function GetCursorPos Lib "user32" (lpPoint As POINTAPI) As Long
Public Declare Function RegisterHotKey Lib "user32" (ByVal hwnd As Long, ByVal id As Long, ByVal fsModifiers As Long, ByVal vk As Long) As Boolean
Public Declare Function UnregisterHotKey Lib "user32" (ByVal hwnd As Long, ByVal id As Long) As Boolean
Public Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Public Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long) As Long
Public Declare Function CallWindowProc Lib "user32" Alias "CallWindowProcA" (ByVal lpPrevWndFunc As Long, ByVal hwnd As Long, ByVal msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Public Declare Function SetWindowPos Lib "user32" _
    (ByVal hwnd As Long, ByVal hWndInsertAfter As Long, _
    ByVal x As Long, ByVal y As Long, ByVal cx As Long, ByVal cy As Long, _
    ByVal wFlags As Long) As Long

Public Declare Function EnumWindows Lib "user32" _
  (ByVal lpEnumFunc As Long, _
   ByVal lParam As Long) As Long
  
Public Declare Function EnumChildWindows Lib "user32" _
  (ByVal hWndParent As Long, _
   ByVal lpEnumFunc As Long, _
   ByRef lParam As Long) As Long

Public Declare Function GetWindowTextLength Lib "user32" _
    Alias "GetWindowTextLengthA" _
   (ByVal hwnd As Long) As Long
   
Public Declare Function GetWindowText Lib "user32" _
    Alias "GetWindowTextA" _
   (ByVal hwnd As Long, _
    ByVal lpString As String, _
    ByVal cch As Long) As Long
   
Public Declare Function GetClassName Lib "user32" _
    Alias "GetClassNameA" _
   (ByVal hwnd As Long, _
    ByVal lpClassName As String, _
    ByVal nMaxCount As Long) As Long

Public Declare Function IsWindowVisible Lib "user32" _
   (ByVal hwnd As Long) As Long
  
Public Declare Function GetParent Lib "user32" _
   (ByVal hwnd As Long) As Long

Public Declare Function SendMessage Lib "user32" _
   Alias "SendMessageA" _
  (ByVal hwnd As Long, _
   ByVal wMsg As Long, _
   ByVal wParam As Long, _
   lParam As Any) As Long
Public Function wndProc(ByVal hwnd As Long, ByVal msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
    If msg = WM_HOTKEY Then
        If wParam = idHotKey Then
            Call frmLookWindow.cmdGetMouseWindow_Click
        End If
    End If
    wndProc = CallWindowProc(preWinProc, hwnd, msg, wParam, lParam)
End Function

'  www.  EnumWindows函数所需要的回调函数
Public Function EnumWindowProc(ByVal hwnd As Long, _
                               ByVal lParam As Long) As Long
    Dim myItem As ListItem
    Dim nSize As Long
    Dim strTitle As String
    Dim strClassName As String
    If GetParent(hwnd) = 0 And IsWindowVisible(hwnd) Then
        Call GetTitleClass(hwnd, strTitle, strClassName)
        Set myItem = frmLookWindow.lvDetail.ListItems.Add(, MakeKey(CStr(hwnd)))
        myItem.Text = strTitle
        myItem.SubItems(1) = strClassName
        myItem.SubItems(2) = hwnd
    End If
    EnumWindowProc = 1
End Function
'  www.  EnumWindows函数所需要的回调函数
Public Function EnumChildWindowProc(ByVal hwnd As Long, _
                                    ByRef lParam As Long) As Long
    Dim myItem As ListItem
    Dim nSize As Long
    Dim strTitle As String
    Dim strClassName As String
    If lParam = 0 Then
        frmLookWindow.lvDetail.ListItems.Clear
    End If
    lParam = 1
    Call GetTitleClass(hwnd, strTitle, strClassName)
    Set myItem = frmLookWindow.lvDetail.ListItems.Add(, "A" & hwnd)
    myItem.Text = strTitle
    myItem.SubItems(1) = strClassName
    myItem.SubItems(2) = hwnd
    EnumChildWindowProc = 1
End Function
'  www.  EnumWindows函数所需要的回调函数
Public Sub GetTitleClass(ByVal hwnd As Long, Title As String, ClassName As String)
    Dim nSize As Long
    Dim strTitle As String
    Dim strClassName As String
    nSize = GetWindowTextLength(hwnd)
    If nSize > 0 Then
        strTitle = Space(255)
        Call GetWindowText(hwnd, strTitle, Len(strTitle))
        strTitle = Trim(strTitle)
    Else
        strTitle = "No Title"
    End If
    strClassName = Space(255)
    Call GetClassName(hwnd, strClassName, Len(strClassName))
    strClassName = Trim(strClassName)
    Title = strTitle
    ClassName = strClassName
End Sub
Public Function GetKey(str As String) As String
    GetKey = Right(str, Len(str) - 1)
End Function
Public Function MakeKey(str As String) As String
    MakeKey = "A" & str
End Function