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用VB编写一个弹出菜单类
作者:佚名  文章来源:不详  点击数  更新时间:2008/4/18 14:44:27  文章录入:杜斌  责任编辑:杜斌

  类的名称为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 GetCursorPos Lib "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()

´ determine # 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 select
   ´ 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)
   ´Debug.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

  ´结束

  ´以下是实例,在Form上添加一个ListBox控件

  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

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