VB:如何?在代碼中彈出toolbar的ButtonMenu

      首先，需要指出的是toolbar的ButtonMenu不是標準的menu，所以用TrackPopupMenu之類的api函數無法達到我們的目的，事實上當使用者點擊dropdown button時，toolbar會發送TBN_DROPDOWN這條通知訊息，所以我們只要用代碼類比發送這條通知訊息即可。代碼如下：

Option Explicit
Private Type TBBUTTON
   iBitmap As Long
   idCommand As Long
   fsState As Byte
   fsStyle As Byte
   bReserved1 As Byte
   bReserved2 As Byte
   dwData As Long
   iString As Long
End Type
Private Type NMHDR
   hwndFrom As Long
   idfrom As Long
   code As Long
End Type

Private Type NMTOOLBAR
    hdr As NMHDR
    iItem As Long
    tbBtn As TBBUTTON
    cchText As Long
    lpszString As Long
End Type
Private Const TBN_FIRST = -700&
Private Const TBN_DROPDOWN = (TBN_FIRST - 10)

Private Const WM_USER = &H400
Private Const TB_GETBUTTON As Long = (WM_USER + 23)
Private Const WM_NOTIFY As Long = &H4E&
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
Private Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal hWnd1 As Long, ByVal hWnd2 As Long, ByVal lpsz1 As String, ByVal lpsz2 As String) As Long

Private Sub Toolbar1_ButtonClick(ByVal Button As MSComctlLib.Button)
    If Button.Index = 4 Then '假如toolbar上的第4個按鈕有buttonmenu，同時其樣式為5
       showbuttonmenu Toolbar1, Button.Index - 1
    End If
End Sub
Private Sub showbuttonmenu(Toolbar1 As MSComctlLib.Toolbar, ByVal Buttonindex As Long) 'buttonindex從0開始
    Dim tButton As TBBUTTON
    Dim tNotify As NMTOOLBAR
    Dim lResult As Long
    Dim mhwnd As Long
    Dim lCommandId As Long
    mhwnd = FindWindowEx(Toolbar1.hwnd, 0, "msvb_lib_toolbar", vbNullString)
    lResult = SendMessage(mhwnd, TB_GETBUTTON, Buttonindex, tButton)
    lCommandId = tButton.idCommand
    With tNotify
        .hdr.code = TBN_DROPDOWN
        .hdr.hwndFrom = mhwnd
        .iItem = lCommandId
    End With
    lResult = SendMessage(Toolbar1.hwnd, WM_NOTIFY, 0, tNotify)
End Sub