用API給普通VB窗體加滾動條.doc

用API給普通VB窗體加滾動條，并響應其消息一、創(chuàng)建一般工程，在窗體上加4個標簽控件，目的是顯示通過API生成的滾動條的數據。名稱分別是：lblmin、lblmax、lblstep、lblpos二、在窗體FORM1的代碼中添加：PrivateSubForm_Load()SUBCLASS窗口，設定新的窗體過程prevProc=GetWindowLong(Form1.hwnd,GWL_WNDPROC)SetWindowLongForm1.hwnd,GWL_WNDPROC,AddressOfwndProc為窗口加載滾動條，并設置其相應參數a.cbSize=Len(a)a.fMask=SIF_ALLa.nMax=3000a.nMin=100a.nPage=hStepa.nPos=100ShowScrollBarForm1.hwnd,SB_BOTH,TrueSetScrollInfoForm1.hwnd,SB_HORZ,a,Truelblmin.Caption=a.nMinlblmax.Caption=a.nMaxlblpos.Caption=a.nPoslblstep.Caption=a.nPageEndSubPrivateSubForm_Unload(CancelAsInteger)恢復窗口的原過程，避免數據丟失SetWindowLongForm1.hwnd,GWL_WNDPROC,prevProcEndSub三、添加一標準模塊。滾動條信息結構體PublicTypeSCROLLINFOcbSizeAsLongfMaskAsLongnMinAsLongnMaxAsLongnPageAsLongnPosAsLongnTrackPosAsLongEndType顯示滾動條與設置滾動條信息函數PublicDeclareFunctionShowScrollBarLibuser32(ByValhwndAsLong,ByValwBarAsLong,ByValbShowAsLong)AsLongPublicDeclareFunctionSetScrollInfoLibuser32(ByValhwndAsLong,ByValnAsLong,lpcScrollInfoAsSCROLLINFO,ByValboolAsBoolean)AsLong滾動條相應常量與標志PublicConstSIF_RANGE=&H1PublicConstSIF_PAGE=&H2PublicConstSIF_POS=&H4PublicConstSIF_ALL=SIF_RANGEOrSIF_PAGEOrSIF_POSPublicConstSB_HORZ=0PublicConstSB_BOTH=3PublicConstSB_BOTTOM=7PublicConstSB_ENDSCROLL=8PublicConstSB_LINEDOWN=1PublicConstSB_LINELEFT=0PublicConstSB_PAGELEFT=2PublicConstSB_PAGERIGHT=3PublicConstSB_LINERIGHT=1PublicConstSB_THUMBTRACK=5PublicConstSB_THUMBPOSITION=4PublicConstSB_TOP=6獲取窗口過程與設置窗口過程函數及其常量PublicDeclareFunctionSetWindowLongLibuser32AliasSetWindowLongA(ByValhwndAsLong,ByValnIndexAsLong,ByValdwNewLongAsLong)AsLongPublicDeclareFunctionGetWindowLongLibuser32AliasGetWindowLongA(ByValhwndAsLong,ByValnIndexAsLong)AsLongPublicDeclareFunctionCallWindowProcLibuser32AliasCallWindowProcA(ByVallpPrevWndFuncAsLong,ByValhwndAsLong,ByValmsgAsLong,ByValwParamAsLong,ByVallParamAsLong)AsLongPublicConstGWL_WNDPROC=(-4)窗體滾動條消息PublicConstWM_HSCROLL=&H114PublicConstWM_VSCROLL=&H115三個全局變量與常量PublicprevProcAsLongPublicaAsSCROLLINFOPublicConsthStep=100PublicFunctionwndProc(ByValhwndAsLong,ByValmsgAsLong,ByValwpAsLong,ByVallpAsLong)AsLongSelectCasemsgCaseWM_HSCROLLCallsetHScrollbar(wp)截取到橫向滾動消息后,調用處理過程CaseWM_VSCROLLCallsetVScrollbar(wp)截取到縱向滾動條消息后,調用處理過程EndSelectwndProc=CallWindowProc(prevProc,hwnd,msg,wp,lp)將滾動條以外的消息交給原過程處理EndFunctionPublicSubsetHScrollbar(ByValwpAsLong)對橫向滾動條的消息進行處理的過程DimposAsLongDimflagAsLongpos=wp65536拖拽時返回的滾動條值flag=wpMod65536判斷滾動條的動作Debug.Print我移動了!&flag&-&posSelectCaseflagCaseSB_LINERIGHT點右按鈕a.nPos=a.nPos+hStepIfa.nPos=a.nMaxThena.nPos=3000SetScrollInfoForm1.hwnd,SB_HORZ,a,TrueCaseSB_LINELEFT點左按鈕a.nPos=a.nPos-hStepIfa.nPos= a.nMin Then a.nPos = 100SetScrollInfo Form1.hwnd, SB_HORZ, a, TrueCase SB_PAGELEFT 點滾動條左邊a.nPos = a.nPos - hStepIf a.nPos =a.nMaxThena.nPos=3000SetScrollInfoForm1.hwnd,SB_HORZ,a,TrueCaseSB_THUMBTRACK拖拽滾動條a.nPos=posSetScrollInfoForm1.hwnd,SB_HORZ,a,TrueCaseSB_BOTTOM到最右端a.nPos=a.nMaxSetScrollInfoForm1.hwnd,SB_HORZ,a,TrueCaseSB_TOP到最左端a.nPos=a.nMinSetScrollInfoForm1.hwnd,SB_HORZ,a,TrueEndSelectForm1.lblpos.Caption=a.nPosEndSubPublicSubsetVScrollbar