关于EnumWindows的问题？
EnumWindows如果没有找到要找的窗口，就让它执行一段代码，该怎么做？
[解决办法]
'Example Name:EnumWindows and EnumChildWindows Callbacks '------------------------------------------'' BAS Moduel Code''------------------------------------------Option Explicit Private Const LVIF_INDENT As Long = &H10Private Const LVIF_TEXT As Long = &H1Private Const LVM_FIRST As Long = &H1000Private Const LVM_SETITEM As Long = (LVM_FIRST + 6)Private 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 LongEnd TypePublic 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, _ ByVal lParam As Long) As LongPrivate Declare Function GetWindowTextLength Lib "user32" _ Alias "GetWindowTextLengthA" _ (ByVal hwnd As Long) As Long Private Declare Function GetWindowText Lib "user32" _ Alias "GetWindowTextA" _ (ByVal hwnd As Long, _ ByVal lpString As String, _ ByVal cch As Long) As Long Private Declare Function GetClassName Lib "user32" _ Alias "GetClassNameA" _ (ByVal hwnd As Long, _ ByVal lpClassName As String, _ ByVal nMaxCount As Long) As LongPrivate Declare Function IsWindowVisible Lib "user32" _ (ByVal hwnd As Long) As Long Private Declare Function GetParent Lib "user32" _ (ByVal hwnd As Long) As LongPrivate Declare Function SendMessage Lib "user32" _ Alias "SendMessageA" _ (ByVal hwnd As Long, _ ByVal wMsg As Long, _ ByVal wParam As Long, _ lParam As Any) As LongPublic Function EnumWindowProc(ByVal hwnd As Long, _ ByVal lParam As Long) As Long 'working vars Dim nSize As Long Dim sTitle As String Dim sClass As String Dim sIDType As String Dim itmX As ListItem Dim nodX As Node 'eliminate windows that are not top-level. If GetParent(hwnd) = 0& And _ IsWindowVisible(hwnd) Then 'get the window title / class name sTitle = GetWindowIdentification(hwnd, sIDType, sClass) 'add to the listview Set itmX = Form1.ListView1.ListItems.Add(Text:=sTitle, Key:=CStr(hwnd) & "h") itmX.SmallIcon = Form1.ImageList1.ListImages("parent").Key itmX.SubItems(1) = CStr(hwnd) itmX.SubItems(2) = sIDType itmX.SubItems(3) = sClass End If 'To continue enumeration, return True 'To stop enumeration return False (0). 'When 1 is returned, enumeration continues 'until there are no more windows left. EnumWindowProc = 1 End FunctionPrivate Function GetWindowIdentification(ByVal hwnd As Long, _ sIDType As String, _ sClass As String) As String Dim nSize As Long Dim sTitle As String 'get the size of the string required 'to hold the window title nSize = GetWindowTextLength(hwnd) 'if the return is 0, there is no title If nSize > 0 Then sTitle = Space$(nSize + 1) Call GetWindowText(hwnd, sTitle, nSize + 1) sIDType = "title" sClass = Space$(64) Call GetClassName(hwnd, sClass, 64) Else 'no title, so get the class name instead sTitle = Space$(64) Call GetClassName(hwnd, sTitle, 64) sClass = sTitle sIDType = "class" End If GetWindowIdentification = TrimNull(sTitle)End FunctionPublic Function EnumChildProc(ByVal hwnd As Long, _ ByVal lParam As Long) As Long 'working vars Dim sTitle As String Dim sClass As String Dim sIDType As String Dim itmX As ListItem 'get the window title / class name sTitle = GetWindowIdentification(hwnd, sIDType, sClass) 'add to the listview Set itmX = Form2.ListView1.ListItems.Add(Text:=sTitle) itmX.SmallIcon = Form2.ImageList1.ListImages("child").Key itmX.SubItems(1) = CStr(hwnd) itmX.SubItems(2) = sIDType itmX.SubItems(3) = sClass Listview_IndentItem Form2.ListView1.hwnd, CLng(itmX.Index), 1 EnumChildProc = 1 End FunctionPrivate Function TrimNull(startstr As String) As String Dim pos As Integer pos = InStr(startstr, Chr$(0)) If pos Then TrimNull = Left$(startstr, pos - 1) Exit Function End If 'if this far, there was 'no Chr$(0), so return the string TrimNull = startstr End FunctionPrivate Sub Listview_IndentItem(hwnd As Long, _ nItem As Long, _ nIndent As Long) Dim LV As LVITEM 'if nIndent indicates that indentation 'is requested nItem is the item to indent If nIndent > 0 Then With LV .mask = LVIF_INDENT .iItem = nItem - 1 'have to subtract 1 .iIndent = nIndent End With Call SendMessage(hwnd, LVM_SETITEM, 0&, LV) End If End Sub'--end block--''------------------------------------------'' Form Code''------------------------------------------Option ExplicitPrivate Sub Command1_Click() ListView1.ListItems.Clear Call EnumWindows(AddressOf EnumWindowProc, &H0)End SubPrivate Sub Form_Load() Me.Move (Screen.Width - Me.Width) / 2, (Screen.Height - Me.Height) / 2End SubPrivate Sub ListView1_DblClick() Dim hwndSelected As Long hwndSelected = Val(ListView1.SelectedItem.Key) Load Form2 Call Form2.EnumSelectedWindow(ListView1.SelectedItem.Text, hwndSelected) End Sub'--end block--' Form2 Code Add the following code to Form2: -------------------------------------------- Option ExplicitPublic Sub EnumSelectedWindow(sItem As String, hwnd As Long) ListView1.ListItems.Clear ListView1.ListItems.Add Text:=sItem, SmallIcon:="parent" Call EnumChildWindows(hwnd, AddressOf EnumChildProc, &H0) Me.Show vbModal End SubPrivate Sub Form_Load() Me.Move (Screen.Width - Me.Width) / 2, (Screen.Height - Me.Height) / 2 End Sub