用VB編寫一個彈出選單類 (轉)

用VB編寫一個彈出選單類 (轉)[@more@]

'類的名稱為cPopupMenu

Option Explicit
'
Private Type POINT
  x As Long
  y As Long
End Type
'
Private Const MF_ENABLED = &H0&
Private Const MF_SEPARATOR = &H800&
Private Const MF_STRING = &H0&
Private Const TPM_RIGHTBUTTON = &H2&
Private Const TPM_LEFTALIGN = &H0&
Private Const TPM_NONOTIFY = &H80&
Private Const TPM_RETURNCMD = &H100&
Private Declare Function CreatePopupMenu Lib "user32" () As Long
Private Declare Function AppendMenu Lib "user32" Alias "AppendMenuA" (ByVal hMenu As Long, ByVal wFlags As Long, ByVal wIDNewItem As Long, ByVal sCaption As String) As Long
Private Declare Function TrackPopupMenu Lib "user32" (ByVal hMenu As Long, ByVal wFlags As Long, ByVal x As Long, ByVal y As Long, ByVal nReserved As Long, ByVal hwnd As Long, nIgnored As Long) As Long
Private Declare Function DestroyMenu Lib "user32" (ByVal hMenu As Long) As Long
Private Declare Function GetCursorPLib "user32" (lpPoint As POINT) As Long
Private Declare Function GetForegroundWindow Lib "user32" () As Long
Private Declare Function GetMenuString Lib "user32" Alias "GetMenuStringA" (ByVal hMenu As Long, ByVal wIDItem As Long, ByVal lpString As String, ByVal nMaxCount As Long, ByVal wFlag As Long) As Long
Private mSelMenuString As String
Public Property Get SelMenuString() As String
  SelMenuString = mSelMenuString
End Property
'
Public Function Popup(ParamArray param()) As Long
  Dim iMenu As Long
  Dim hMenu As Long
  Dim nMenus As Long
  Dim p As POINT

' get the current cursor pos in screen coordinates
  GetCursorPos p

' create an empty popup menu
  hMenu = CreatePopupMenu()

' detene # of strings in paramarray
  nMenus = 1 + UBound(param)

' put each string in the menu
  For iMenu = 1 To nMenus
' the AppendMenu function has been superseeded by the InsertMenuItem
' function, but it is a bit easier to use.
  If Trim$(CStr(param(iMenu - 1))) = "-" Then
' if the parameter is a single dash, a separator is drawn
  AppendMenu hMenu, MF_SEPARATOR, iMenu, ""
  Else
  AppendMenu hMenu, MF_STRING + MF_ENABLED, iMenu, CStr(param(iMenu - 1))
  End If
  Next iMenu

' show the menu at the current cursor location;
' the flags make the menu aligned to the right (!); enable the right button to
' an item; prohibit the menu from sending messages and make it return the index of
' the selected item.
' the TrackPopupMenu function returns when the user selected a menu item or cancelled
' the window handle used here may be any window handle from your application
' the return value is the (1-based) index of the menu item or 0 in case of cancelling
  iMenu = TrackPopupMenu(hMenu, TPM_RIGHTBUTTON + TPM_LEFTALIGN + TPM_NONOTIFY + TPM_RETURNCMD, p.x, p.y, 0, GetForegroundWindow(), 0)
  Dim result As Long
  Dim buffer As String
  Const MF_BYPOSITION = &H400&

  buffer = Space(255)
 
  result = GetMenuString(hMenu, (iMenu - 1), buffer, _
  Len(buffer), MF_BYPOSITION)
  'De.Print buffer
  mSelMenuString = Trim(buffer)
' release and destroy the menu (for sanity)
  DestroyMenu hMenu

' return the selected menu item's index
  Popup = iMenu

End Function

'結束

'以下是例項，在Form上新增一個ListBox

Option Explicit

Private Sub Form_Load()
  List1.AddItem "Right-Click here for a menu"
End Sub

Private Sub List1_MouseUp(Button As Integer, Shift As Integer, x As Single, y As Single)
  Dim oMenu As cPopupMenu
  Dim lMenuChosen As Long
'
  If Button = vbRightButton Then
  Set oMenu = New cPopupMenu
'
' Pass in the desired menu, use '-' for a separator
'
  lMenuChosen = oMenu.Popup("Menu 1", "Menu 2", "Menu 3", _
  "-", "Menu 4")
'
  Debug.Print lMenuChosen
  Debug.Print oMenu.SelMenuString
  End If

'
End Sub