2002年2月 Delphi大版内专家分月排行榜第三
本帖子已过去太久远了，不再提供回复功能。VB 6.0 中的AddressOf使用问题，请教各位大侠。做activex客户端控件时， 在共用方法中调用Addressof提示 调用无效， google了一番， 都说addressof要在类模块中当参数使用。 由于工作需要刚接触vb， 请教各位大侠， 如何在类模块中使用addressof， 具体步骤是怎么的啊？　　VB code　　 Dim strtest As String Public Function EnumChildProc(ByVal hwnd As Long, ByVal lParam As Long) As Long
Dim slength As Long, wintext As String ' title bar text length and buffer
Dim retval As Long ' return value
Dim Buffer As String
Buffer = Space(slength) ' make room in the buffer
retval = GetWindowText(hwnd, Buffer, slength) ' get title bar text
strtest = strtest & &---& & retval
EnumChildProc = 1 ' return value of 1 means continue enumeration End Function
调用方法 Dim lHandle As Long lHandle = FindWindow(vbNullString, &软件窗体名称&) Dim retval As Long ' return value retval = EnumChildWindows(lHandle, AddressOf EnumChildProc, 0)
AddressOf只能在标准模块中使用参阅：使用 AddressOf 关键字如果代码要调用 Visual Basic 5.0 的函数指针，则必须将该代码放到标准的 .BAS 模块中，不可以将其放到类模块中，也不能将其附加到窗体上。在使用 AddressOf 关键字声明函数时，必须注意下列事项：& AddressOf 只能紧接在是参数列表中的参数前；该参数可以是自定义的过程、函数或者属性的名字。写在 AddressOf 后面的过程、函数、属性必须与有关的声明和过程在同一个工程中。AddressOf 只能用于自定义的过程、函数和属性，不能将其用于 Declare 语句声明的外部函数，也不能将其用于类型库中的函数。在声明的 Sub、Function 或自定义的类型定义中，可以将函数指针传递到 As Any 或 As Long 类型的参数。& 注意
可创建用 Visual C++ （或类似的工具）编译的 DLL 中的回调函数原型。要使用 AddressOf 时，原型必须使用 __stdcall 调用约定。不能将缺省调用约定与 AddressOf 并用
　　VB code　　'Example Name:EnumWindows and EnumChildWindows Callbacks
'------------------------------------------
' BAS Moduel Code
'------------------------------------------
Option Explicit
Private Const LVIF_INDENT As Long = &H10
Private Const LVIF_TEXT As Long = &H1
Private Const LVM_FIRST As Long = &H1000
Private 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 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, _
ByVal lParam As Long) As Long
Private 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 Long
Private Declare Function IsWindowVisible Lib &user32& _
(ByVal hwnd As Long) As Long
Private Declare Function GetParent Lib &user32& _
(ByVal hwnd As Long) As Long
Private 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 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
'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 Function
Private 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)
'no title, so get the class name instead
sTitle = Space$(64)
Call GetClassName(hwnd, sTitle, 64)
sClass = sTitle
sIDType = &class&
GetWindowIdentification = TrimNull(sTitle)
End Function
Public Function EnumChildProc(ByVal hwnd As Long, _
ByVal lParam As Long) As Long
'working vars
Dim sTitle As String
Dim sClass As String
Dim sIDType As String
Dim itmX As ListItem
'get the window title / class name
sTitle = GetWindowIdentification(hwnd, sIDType, sClass)
'add to the listview
Set itmX = Form2.ListView1.ListItems.Add(Text:=sTitle)
itmX.SmallIcon = Form2.ImageList1.ListImages(&child&).Key
itmX.SubItems(1) = CStr(hwnd)
itmX.SubItems(2) = sIDType
itmX.SubItems(3) = sClass
Listview_IndentItem Form2.ListView1.hwnd, CLng(itmX.Index), 1
EnumChildProc = 1
End Function
Private Function TrimNull(startstr As String) As String
Dim pos As Integer
pos = InStr(startstr, Chr$(0))
If pos Then
TrimNull = Left$(startstr, pos - 1)
Exit Function
'if this far, there was
'no Chr$(0), so return the string
TrimNull = startstr
End Function
Private 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
.mask = LVIF_INDENT
.iItem = nItem - 1 'have to subtract 1
.iIndent = nIndent
Call SendMessage(hwnd, LVM_SETITEM, 0&, LV)
'--end block--'
'------------------------------------------
' Form Code
'------------------------------------------
Option Explicit
Private Sub Command1_Click()
ListView1.ListItems.Clear
Call EnumWindows(AddressOf EnumWindowProc, &H0)
Private Sub Form_Load()
Me.Move (Screen.Width - Me.Width) / 2, (Screen.Height - Me.Height) / 2
Private Sub ListView1_DblClick()
Dim hwndSelected As Long
hwndSelected = Val(ListView1.SelectedItem.Key)
Load Form2
Call Form2.EnumSelectedWindow(ListView1.SelectedItem.Text, hwndSelected)
'--end block--'
Form2 Code
Add the following code to Form2:
--------------------------------------------
Option Explicit
Public 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
Private Sub Form_Load()
Me.Move (Screen.Width - Me.Width) / 2, (Screen.Height - Me.Height) / 2