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----創(chuàng)建位圖菜單其實(shí)非常簡單,它需要用到Windows應(yīng)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(yīng)用程序的標(biāo)準(zhǔn)模 塊中,具體的內(nèi)容請(qǐng)參見樣例程序。步驟如下:
使用函數(shù)GetSubMenu來提取子菜單項(xiàng)的句柄,并通過使用函數(shù)CreateCompatibleDC 來創(chuàng)建一個(gè)兼容的設(shè)備環(huán)境描述表; 在一個(gè)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(duì)各個(gè)菜單項(xiàng)所載入的位圖選入到兼容設(shè)備環(huán)境中; 通過ModifyMenu函數(shù)繪制真正的位圖菜單選項(xiàng); 使用DeleteDC函數(shù)來釋放設(shè)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(shè)置了四個(gè)圖形框控件, 使用它們載入4個(gè)預(yù)設(shè)的圖標(biāo)來作為菜單選項(xiàng)位圖的源文件,當(dāng)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(gè)新的工程,采用缺省的方法建立Form1。 創(chuàng)建一個(gè)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(nèi)。 在Form1上添加4個(gè)圖形框控件,將它們的Name屬性設(shè)置為Picture1,將它們的 Index屬性依次設(shè)置為0,1,2,3,將它們的AutoRedrew屬性設(shè)置為True,將它們 的AutoResize屬性設(shè)置為Ture,以及將它們的Visable屬性設(shè)置為False。 將上面的4個(gè)圖形框控件的Picture屬性依次設(shè)置為Face1.ico,F(xiàn)ace2.ico,F(xiàn)ace3. ico,F(xiàn)ace4.ico。 在Form1上添加第一個(gè)菜單項(xiàng),將它的標(biāo)題設(shè)置為“[&F]文件”,名稱設(shè)置為 mnuFile。在其下添加一個(gè)子菜單項(xiàng),將它的標(biāo)題設(shè)置為“[&E]退出”,名稱設(shè)置 為mnuExit。 在Form1上添加第二個(gè)菜單項(xiàng),將它的標(biāo)題設(shè)置為“[&A]臉譜”,名稱設(shè)置為 mnuFace。在其下添加4個(gè)子菜單項(xiàng),分別將改4個(gè)子菜單項(xiàng)的名稱設(shè)置為“[N]正常” ,“[&S]微笑”,“ [&L]大笑”,以及“[&O]悲傷”。將它們的名稱設(shè)置為“ mnuFaceSel”,并相應(yīng)將這4個(gè)子菜單項(xiàng)的索引設(shè)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(yùn)行該樣例程序,單擊“臉譜”菜單,則會(huì)看到由4個(gè)臉譜圖標(biāo)所形成的位圖子菜 單項(xiàng),單擊“文件”\“退出”菜單可退出應(yīng)用程序。
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