----創(chuàng)建位圖菜單其實非常簡單,它需要用到Windows應用程序編程接口(API)的 一些菜單函數(shù)和位圖函數(shù),你需要將這些函數(shù)的聲明包含在你的應用程序的標準模 塊中,具體的內容請參見樣例程序。步驟如下:
使用函數(shù)GetSubMenu來提取子菜單項的句柄,并通過使用函數(shù)CreateCompatibleDC 來創(chuàng)建一個兼容的設備環(huán)境描述表; 在一個循環(huán)過程中通過使用CreateCompatibleBitmap函數(shù),SelectObject函數(shù)以及 BitBlt函數(shù)來分別將針對各個菜單項所載入的位圖選入到兼容設備環(huán)境中; 通過ModifyMenu函數(shù)繪制真正的位圖菜單選項; 使用DeleteDC函數(shù)來釋放設備環(huán)境,以便其他的程序可以使用它們。 ----提取位圖可以有多種方法,在本樣例程序中在窗體上設置了四個圖形框控件, 使用它們載入4個預設的圖標來作為菜單選項位圖的源文件,當然你也可以使用其 他的方法,例如使用LoadPicture函數(shù)來從磁盤裝載位圖。
樣例程序
在Visual Basic中開始一個新的工程,采用缺省的方法建立Form1。 創(chuàng)建一個新的模塊,采用缺省的方法建立Module1.Bas。 將如下的聲明語句和常量添加到Module1.Bas模塊中: Option Explicit Declare Function GetMenu Lib "user32" (ByVal hwnd As Long) As Long Declare Function GetSubMenu Lib "user32" (ByVal hMenu As Long, ByVal nPos As Long) As Long Declare Function GetMenuItemID Lib "user32" (ByVal hMenu As Long, ByVal nPos As Long) As Long Declare Function ModifyMenu Lib "user32" Alias "ModifyMenuA" (ByVal hMenu As Long,ByVal nPosition As Long, ByVal wFlags As Long, ByVal wIDNewItem As Long, ByVal lpString As Any) As Long Declare Function CreateCompatibleDC Lib "gdi32" (ByVal hdc As Long) As Long Declare Function DeleteDC Lib "gdi32" (ByVal hdc As Long) As Long Declare Function CreateCompatibleBitmap Lib "gdi32" (ByVal hdc As Long, ByVal nWidth As Long, ByVal nHeight As Long) As Long Declare Function SelectObject Lib "gdi32" (ByVal hdc As Long, ByVal hObject As Long) As Long Declare Function BitBlt Lib "gdi32" (ByVal hDestDC As Long, ByVal x As Long, ByVal y As Long, ByVal nWidth As Long, ByVal nHeight As Long, ByVal hSrcDC As Long, ByVal xSrc As Long, ByVal ySrc As Long, ByVal dwRop As Long) As Long Public Const SRCCOPY = &HCC0020 Public Const MF_BYPOSITION = &H400& Public Const MF_BITMAP = &H4&
注意上面的聲明語句需要書寫在一行內。 在Form1上添加4個圖形框控件,將它們的Name屬性設置為Picture1,將它們的 Index屬性依次設置為0,1,2,3,將它們的AutoRedrew屬性設置為True,將它們 的AutoResize屬性設置為Ture,以及將它們的Visable屬性設置為False。 將上面的4個圖形框控件的Picture屬性依次設置為Face1.ico,F(xiàn)ace2.ico,F(xiàn)ace3. ico,F(xiàn)ace4.ico。 在Form1上添加第一個菜單項,將它的標題設置為“[&F]文件”,名稱設置為 mnuFile。在其下添加一個子菜單項,將它的標題設置為“[&E]退出”,名稱設置 為mnuExit。 在Form1上添加第二個菜單項,將它的標題設置為“[&A]臉譜”,名稱設置為 mnuFace。在其下添加4個子菜單項,分別將改4個子菜單項的名稱設置為“[N]正常” ,“[&S]微笑”,“ [&L]大笑”,以及“[&O]悲傷”。將它們的名稱設置為“ mnuFaceSel”,并相應將這4個子菜單項的索引設置為0,1,2,3。 將如下的代碼添加到Form1的Form_Load事件中: Private Sub Form_Load() Dim nLoopCtr As Integer Dim lResult As Long Dim hTempDC As Long Dim nWidth As Integer Dim nHeight As Integer Dim lTempID As Long Dim hMenuID As Long Dim lItemCount As Long Dim hBitmap As Long nWidth = Picture1(nLoopCtr).Width \ Screen.TwipsPerPixelX nHeight = Picture1(nLoopCtr).Height \ Screen.TwipsPerPixelY hMenuID = GetSubMenu(GetMenu((Me.hwnd)), 1) hTempDC = CreateCompatibleDC(Picture1(nLoopCtr).hdc) For nLoopCtr = 0 To 3 hBitmap = CreateCompatibleBitmap(Picture1(nLoopCtr).hdc, nWidth, nHeight) lTempID = SelectObject(hTempDC, hBitmap) lResult = BitBlt(hTempDC, 0, 0, nWidth, nHeight, (Picture1( nLoopCtr).hdc), 0, 0, SRCCOPY) lTempID = SelectObject(hTempDC, lTempID) nuFaceSel(nLoopCtr).Caption = "" lResult = ModifyMenu(hMenuID, nLoopCtr, MF_BYPOSITION Or MF_BITMAP, GetMenuItemID(hMenuID, nLoopCtr), hBitmap) Next nLoopCtr lResult = DeleteDC(hTempDC) End Sub 將如下的代碼添加到“退出”子菜單的單擊事件中: Private Sub mnuExit_Click(Index As Integer) Select Case Index Case 0 Unload Me End Select End Sub 運行該樣例程序,單擊“臉譜”菜單,則會看到由4個臉譜圖標所形成的位圖子菜 單項,單擊“文件”\“退出”菜單可退出應用程序。
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