用API给普通VB窗体加滚动条.doc

用API给普通VB窗体加滚动条，并响应其消息一、创建一般工程，在窗体上加4个标签控件，目的是显示通过API生成的滚动条的数据。名称分别是：lblmin、lblmax、lblstep、lblpos二、在窗体FORM1的代码中添加：PrivateSubForm_Load()SUBCLASS窗口，设定新的窗体过程prevProc=GetWindowLong(Form1.hwnd,GWL_WNDPROC)SetWindowLongForm1.hwnd,GWL_WNDPROC,AddressOfwndProc为窗口加载滚动条，并设置其相应参数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)恢复窗口的原过程，避免数据丢失SetWindowLongForm1.hwnd,GWL_WNDPROC,prevProcEndSub三、添加一标准模块。滚动条信息结构体PublicTypeSCROLLINFOcbSizeAsLongfMaskAsLongnMinAsLongnMaxAsLongnPageAsLongnPosAsLongnTrackPosAsLongEndType显示滚动条与设置滚动条信息函数PublicDeclareFunctionShowScrollBarLibuser32(ByValhwndAsLong,ByValwBarAsLong,ByValbShowAsLong)AsLongPublicDeclareFunctionSetScrollInfoLibuser32(ByValhwndAsLong,ByValnAsLong,lpcScrollInfoAsSCROLLINFO,ByValboolAsBoolean)AsLong滚动条相应常量与标志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获取窗口过程与设置窗口过程函数及其常量PublicDeclareFunctionSetWindowLongLibuser32AliasSetWindowLongA(ByValhwndAsLong,ByValnIndexAsLong,ByValdwNewLongAsLong)AsLongPublicDeclareFunctionGetWindowLongLibuser32AliasGetWindowLongA(ByValhwndAsLong,ByValnIndexAsLong)AsLongPublicDeclareFunctionCallWindowProcLibuser32AliasCallWindowProcA(ByVallpPrevWndFuncAsLong,ByValhwndAsLong,ByValmsgAsLong,ByValwParamAsLong,ByVallParamAsLong)AsLongPublicConstGWL_WNDPROC=(-4)窗体滚动条消息PublicConstWM_HSCROLL=&H114PublicConstWM_VSCROLL=&H115三个全局变量与常量PublicprevProcAsLongPublicaAsSCROLLINFOPublicConsthStep=100PublicFunctionwndProc(ByValhwndAsLong,ByValmsgAsLong,ByValwpAsLong,ByVallpAsLong)AsLongSelectCasemsgCaseWM_HSCROLLCallsetHScrollbar(wp)截取到横向滚动消息后,调用处理过程CaseWM_VSCROLLCallsetVScrollbar(wp)截取到纵向滚动条消息后,调用处理过程EndSelectwndProc=CallWindowProc(prevProc,hwnd,msg,wp,lp)将滚动条以外的消息交给原过程处理EndFunctionPublicSubsetHScrollbar(ByValwpAsLong)对横向滚动条的消息进行处理的过程DimposAsLongDimflagAsLongpos=wp65536拖拽时返回的滚动条值flag=wpMod65536判断滚动条的动作Debug.Print我移动了!&flag&-&posSelectCaseflagCaseSB_LINERIGHT点右按钮a.nPos=a.nPos+hStepIfa.nPos=a.nMaxThena.nPos=3000SetScrollInfoForm1.hwnd,SB_HORZ,a,TrueCaseSB_LINELEFT点左按钮a.nPos=a.nPos-hStepIfa.nPos= a.nMin Then a.nPos = 100SetScrollInfo Form1.hwnd, SB_HORZ, a, TrueCase SB_PAGELEFT 点滚动条左边a.nPos = a.nPos - hStepIf a.nPos =a.nMaxThena.nPos=3000SetScrollInfoForm1.hwnd,SB_HORZ,a,TrueCaseSB_THUMBTRACK拖拽滚动条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