1、第四講：鼠標只要鼠標跨越窗口，或者在某窗口中按下鼠標按鈕，那么窗口過程函數就會收到鼠標消息，而不管該窗口是否為活動窗口和是否擁有輸入焦點窗口。鼠標消息：1. lParam是相對于客戶區左上角的坐標，其中X坐標:LOWORD(IParam)Y坐標:HIWORD(lParam)2. wParam是Shift鍵和Ctrl鍵或鼠標按鈕的狀態，若wParam&MK_SHIFT0wParam&MK_CONTROL0wParam&MK_LBUTTON0wParam&MK_MBUTTON0wParam&MK_RBUTTON0表示在產生相應的鼠標消息時，也按下了Shift鍵和Ctrl鍵或鼠標按鈕。WM_LBUT

2、TONDOWNWM_MBUTTONDOWNWM_RBUTTONDOWNWM_LBUTTONUPWM_RBUTTONUPWM_MBUTTONUPWM_LBUTTONDBLCLKWM_MBUTTONDBLCLKWM_RBUTTONDBLCLKWM_MOUSEMOVE鼠標雙擊消息如果希望窗口過程函數能接受鼠標雙擊消息，那么在注冊窗口類時，窗口風格應為：wndclass.style=CS_HREDRAW|CS_VREDRAW|CS_DBLCLKS;重點：鼠標消息：WM_LBUTTONDOWNWM_MBUTTONDOWNWM_RBUTTONDOWNWM_LBUTTONUPWM_RBUTTONUPWM_M

3、BUTTONUPWM_LBUTTONDBLCLKWM_MBUTTONDBLCLKWM_RBUTTONDBLCLKWM_MOUSEMOVE子窗口風格：WS_CHILDWINDOW|WS_VISIBLE取程序實例句柄：(HINSTANCE)GetWindowLong(hwnd,GWL_HINSTANCE)函數MoveWindow(hwndChildxy,x*cxBIock,y*cyBlock,cxBIock,cyBlock,TRUE);移動窗口和改變窗口大小尺寸，產生WM_SIZE消息。存取預留在窗口額外字節的函數:SetWindowLong(hwnd,0,0);GetWindowLong(hwn

4、d,0,0);設置窗口捕獲鼠標函數：SetCapture(hwnd)旦窗口hwnd被設置了捕獲鼠標，不管鼠標光標是否在窗口hwnd的邊界之內，窗口hwnd都接受鼠標輸入。釋放窗口捕獲鼠標函數：ReleaseCapture();WM_MOUSEMOVE消息：每當鼠標移動時，窗口接收WM_MOUSEMOVE消息，系統此時自動把鼠標光標形狀切換到在窗口類中定義的鼠標光標形狀，如wndclass.hCursor=LoadCursor(NULL,IDC_ARROW);/*CONNECT.C-Connect-the-DotsMouseDemoProgram(c)CharlesPetzold,1998*/#

5、include#defineMAXPOINTS1000LRESULTCALLBACKWndProc(HWND,UINT,WPARAM,LPARAM);intWINAPIWinMain(HINSTANCEhlnstanee,HINSTANCEhPrevInstanee,PSTRszCmdLine,intiCmdShow)staticTCHARszAppName=TEXT(Connect);HWNDhwnd;MSGmsg;WNDCLASSwndclass;wndclass.stylewndclass.hCursor=CS_HREDRAW|CS_VREDRAW;=WndProc;=0;=0;=hln

6、stanee;=LoadIcon(NULL,IDI_APPLICATION);=LoadCursor(NULL,IDC_ARROW);wndclass.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);wndclass.lpszMenuName=NULL;wndclass.lpszClassName=szAppName;if(!RegisterClass(&wndclass)MessageBox(NULL,TEXT(ProgramrequiresWindowsNT!),szAppName,MB_ICONERROR);return0;hwnd=C

7、reateWindow(szAppName,TEXT(Connect-the-PointsMouseDemo),WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,NULL,NULL,hInstanee,NULL);ShowWindow(hwnd,iCmdShow);UpdateWindow(hwnd);while(GetMessage(&msg,NULL,0,0)TranslateMessage(&msg);DispatchMessage(&msg);returnmsg.wParam;wPar

8、am,LRESULTCALLBACKWndProc(HWNDhwnd,UINTmessage,WPARAMLPARAMIParam)staticPOINTptMAXPOINTS;staticintiCount;HDChdc;inti,j；PAINTSTRUCTps;switch(message)caseWM_LBUTTONDOWN:iCount=0;InvalidateRect(hwnd,NULL,TRUE);return0;caseWM_MOUSEMOVE:if(wParam&MK_LBUTTON&iCount1000)ptiCount.x=LOWORD(IParam);ptiCount+.

9、y=HIWORD(IParam);hdc=GetDC(hwnd);/SetPixel(hdc,LOWORD(IParam),HIWORD(IParam),0);SetPixel(hdc,LOWORD(lParam),HIWORD(lParam),RGB(255,0,0);ReleaseDC(hwnd,hdc);return0;caseWM_LBUTTONUP:InvalidateRect(hwnd,NULL,FALSE);return0;caseWM_PAINT:hdc=BeginPaint(hwnd,&ps);SetCursor(LoadCursor(NULL,IDC_WAIT);ShowC

10、ursor(TRUE);for(i=0;iiCount-1;i+)for(j=i+1;jiCount;j+)MoveToEx(hdc,pti.x,pti.y,NULL);LineTo(hdc,ptj.x,ptj.y);ShowCursor(FALSE);SetCursor(LoadCursor(NULL,IDC_ARROW);EndPaint(hwnd,&ps);return0;caseWM_DESTROY:PostQuitMessage(0);return0;returnDefWindowProc(hwnd,message,wParam,lParam);/*CHECKER1.C-MouseH

11、it-TestDemoProgramNo.1(c)CharlesPetzold,1998*/#include#defineDIVISIONS5LRESULTCALLBACKWndProc(HWND,UINT,WPARAM,LPARAM);intWINAPIWinMain(HINSTANCEhlnstanee,HINSTANCEhPrevInstanee,PSTRszCmdLine,intiCmdShow)staticTCHARszAppName=TEXT(Checkerl);HWNDhwnd;MSGmsg;WNDCLASSwndclass;wndclass.stylewndclass.1pfn

12、WndProcwndclass.cbCIsExtra=CS_HREDRAW|CS_VREDRAW;=WndProc;=0；=0；=hlnstanee;=LoadIcon(NULL,IDI_APPLICATION);=LoadCursor(NULL,IDC_ARROW);wndclass.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);wndclass.lpszMenuName=NULL;wndclass.lpszClassName=szAppName;if(!RegisterClass(&wndclass)MessageBox(NULL,TE

13、XT(ProgramrequiresWindowsNT!),szAppName,MB_ICONERROR);return0;hwnd=CreateWindow(szAppName,TEXT(CheckerlMouseHit-TestDemo),WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,NULL,NULL,hInstanee,NULL);ShowWindow(hwnd,iCmdShow);UpdateWindow(hwnd);while(GetMessage(&msg,NULL,0,0)

14、TranslateMessage(&msg);DispatchMessage(&msg);returnmsg.wParam;wParam,LRESULTCALLBACKWndProc(HWNDhwnd,UINTmessage,WPARAMLPARAMIParam)staticBOOLfStateDIVISIONSDIVISIONS;staticintcxBlock,cyBlock;HDChdc;intx,y;PAINTSTRUCTps;RECTrect;switch(message)caseWM_SIZE:cxBlock=LOWORD(IParam)/DIVISIONS;cyBlock=HIW

15、ORD(IParam)/DIVISIONS;return0;caseWM_LBUTTONDOWN:x=LOWORD(lParam)/cxBlock;y=HIWORD(lParam)/cyBlock;if(xDIVISIONS&yDIVISIONS)fStatexyA=1;rect.left=x*cxBlock;rect.top=y*cyBlock;rect.right=(x+1)*cxBlock;rect.bottom=(y+1)*cyBlock;InvalidateRect(hwnd,&rect,FALSE);elseMessageBeep(0);return0;caseWM_PAINT:h

16、dc=BeginPaint(hwnd,&ps);for(x=0;xDIVISIONS;x+)for(y=0;yDIVISIONS;y+)Rectangle(hdc,x*cxBIock,y*cyBlock,(x+1)*cxBlock,(y+1)*cyBlock);if(fState兇y)MoveToEx(hdc,x*cxBlock,y*cyBlock,NULL);LineTo(hdc,(x+1)*cxBlock,(y+1)*cyBlock);MoveToEx(hdc,x*cxBlock,(y+1)*cyBlock,NULL);LineTo(hdc,(x+1)*cxBlock,y*cyBlock)

17、;EndPaint(hwnd,&ps);return0;caseWM_DESTROY:PostQuitMessage(0);return0;returnDefWindowProc(hwnd,message,wParam,lParam);/*CHECKER3.C-MouseHit-TestDemoProgramNo.3(c)CharlesPetzold,1998*/#include#defineDIVISIONS5LRESULTCALLBACKWndProc(HWND,UINT,WPARAM,LPARAM);LRESULTCALLBACKChildWndProc(HWND,UINT,WPARAM

18、,LPARAM);TCHARszChildClass=TEXT(Checker3_Child);intWINAPIWinMain(HINSTANCEhlnstanee,HINSTANCEhPrevInstanee,PSTRszCmdLine,intiCmdShow)staticTCHARszAppName=TEXT(Checker3);HWNDhwnd;MSGMSGmsg;WNDCLASSwndclass;wndclass.stylewndclass.lpfnWndProcwndclass.cbCIsExtra=CS_HREDRAW|CS_VREDRAW;=WndProc;=0;=0；=hln

19、stanee;=Loadlcon(NULL,IDI_APPLICATION);=LoadCursor(NULL,IDC_ARROW);wndclass.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);wndclass.lpszMenuName=NULL;wndclass.lpszClassName=szAppName;if(!RegisterClass(&wndclass)MessageBox(NULL,TEXT(ProgramrequiresWindowsNT!),szAppName,MB_ICONERROR);return0;wndcla

20、ss.lpfnWndProc=ChildWndProc;wndclass.cbWndExtra=sizeof(long);wndclass.hIcon=NULL;wndclass.lpszClassName=szChildClass;RegisterClass(&wndclass);hwnd=CreateWindow(szAppName,TEXT(Checker3MouseHit-TestDemo),WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,NULL,NULL,hInstanee,NU

21、LL);ShowWindow(hwnd,iCmdShow);UpdateWindow(hwnd);while(GetMessage(&msg,NULL,0,0)TranslateMessage(&msg);DispatchMessage(&msg);returnmsg.wParam;LRESULTCALLBACKWndProc(HWNDhwnd,UINTmessage,WPARAMLPARAMIParam)staticHWNDhwndChildDIVISIONSDIVISIONS;intcxBIock,cyBIock,x,y;switch(message)caseWM_CREATE:for(x

22、=0;xDIVISIONS;x+)for(y=0;yDIVISIONS;y+)hwndChildxy=CreateWindow(szChildCIass,NULL,WS_CHILDWINDOW|WS_VISIBLE,0,0,0,0,hwnd,(HMENU)(y8|x),(HINSTANCE)GetWindowLongGWL_HINSTANCE),NULL);return0;caseWM_SIZE:cxBIock=LOWORD(IParam)/DIVISIONS;cyBIock=HIWORD(IParam)/DIVISIONS;for(x=0;xDIVISIONS;x+)for(y=0;yDIV

23、ISIONS;y+)MoveWindow(hwndChildxy,x*cxBIock,y*cyBIock,cxBIock,cyBIock,TRUE);return0;caseWM_LBUTTONDOWN:MessageBeep(0);return0;caseWM_DESTROY:PostQuitMessage(0);return0;returnDefWindowProc(hwnd,message,wParam,IParam);wParam,(hwnd,LRESULTCALLBACKChildWndProc(HWNDhwnd,UINTmessage,WPARAMwParam,LPARAMIPar

24、am)HDChdc;PAINTSTRUCTps;RECTrect;switch(message)/on/offflag/on/offflagcaseWM_CREATE:SetWindowLong(hwnd,0,0);return0;caseWM_LBUTTONDOWN:SetWindowLong(hwnd,0,1AGetWindowLong(hwnd,0);InvalidateRect(hwnd,NULL,FALSE);return0;caseWM_PAINT:hdc=BeginPaint(hwnd,&ps);GetClientRect(hwnd,&rect);Rectangle(hdc,0,

25、0,rect.right,rect.bottom);if(GetWindowLong(hwnd,0)MoveToEx(hdc,0,0,NULL);LineTo(hdc,rect.right,rect.bottom);MoveToEx(hdc,0,rect.bottom,NULL);LineTo(hdc,rect.right,0);EndPaint(hwnd,&ps);return0;returnDefWindowProc(hwnd,message,wParam,lParam);相關函數SetPixelTheSetPixelfunctionsetsthepixelatthespecifiedco

26、ordinatestothespecifiedcolor.COLORREFSetPixel(/handletoDCHDChdc,intXintY,COLORREFcrColorintXintY,COLORREFcrColor/x-coordinateofpixel/y-coordinateofpixel/pixelcolor);ParametershdcinHandletothedevicecontext.inSpecifiesthex-coordinate,inlogicalunits,ofthepointtobeset.inSpecifiesthey-coordinate,inlogica

27、lunits,ofthepointtobeset.crColorinSpecifiesthecolortobeusedtopaintthepoint.TocreateaCOLORREFcolorvalue,usetheRGBmacro.ReturnValuesIfthefunctionsucceeds,thereturnvalueistheRGBvaluethatthefunctionsetsthepixelto.ThisvaluemaydifferfromthecolorspecifiedbycrColor;thatoccurswhenanexactmatchforthespecifiedc

28、olorcannotbefound.Ifthefunctionfails,thereturnvalueis1.SetCursorTheSetCursorfunctionsetsthecursorshape.HCURSORSetCursor(HCURSORhCursor/handletocursor);ParametershCursorinHandletothecursor.ThecursormusthavebeencreatedbytheCreateCursorfunctionorloadedbytheLoadCursororLoadImagefunction.Ifthisparameteri

29、sNULL,thecursorisremovedfromthescreen.ReturnValuesThereturnvalueisthehandletothepreviouscursor,iftherewasone.Iftherewasnopreviouscursor,thereturnvalueisNULL.LoadCursorTheLoadCursorfunctionloadsthespecifiedcursorresourcefromtheexecutable(.EXE)fileassociatedwithanapplicationinstanee.HCURSORLoadCursor(

30、HINSTANCEhlnstanee,/handletoapplicationinstaneeLPCTSTRlpCursorName/nameorresourceidentifier)；LoadCursor(NULL,IDC_WAIT)IDC_ARROW,IDC_CROSS,IDC_WAITMoveToExTheMoveToExfunctionupdatesthecurrentpositiontothespecifiedpointandoptionallyreturnsthepreviousposition.BOOLMoveToEx(HDChdc,/handletodevicecontexti

31、ntX,/x-coordinateofnewcurrentpositionintY,/y-coordinateofnewcurrentpositionLPPOINTlpPoint/oldcurrentposition)；ParametershdcinHandletoadevicecontext.XinSpecifiesthex-coordinateofthenewposition,inlogicalunits.YinSpecifiesthey-coordinateofthenewposition,inlogicalunits.lpPointoutPointertoaPOINTstructure

32、thatreceivesthepreviouscurrentposition.IfthisparameterisaNULLpointer,thepreviouspositionisnotreturned.ReturnValuesIfthefunctionsucceeds,thereturnvalueisnonzero.Ifthefunctionfails,thereturnvalueiszero.LineToTheLineTofunctiondrawsalinefromthecurrentpositionupto,butnotincluding,thespecifiedpoint.BOOLLi

33、neTo(HDChdc,/devicecontexthandleintnXEnd/x-coordinateofendingpointintnYEnd/y-coordinateofendingpoint);ParametershdcinHandletoadevicecontext.nXEndinSpecifiesthex-coordinateofthelinesendingpoint,nYEndinSpecifiesthey-coordinateofthelinesendingpoint.ReturnValuesIfthefunctionsucceeds,thereturnvalueisnonz

34、ero.Ifthefunctionfails,thereturnvalueiszero.RectangleBOOLRectangle(HDChdc,intnLeftRect,intnTopRect,intnRightRect:BOOLRectangle(TheRectanglefunctiondrawsarectangle.Therectangleisoutlinedbyusingthecurrentpenandfilledbyusingthecurrentbrush./handletoDC/x-coordofupper-leftcornerofrectangle/y-coordofupper

35、-leftcornerofrectangle/x-coordoflower-rightcornerofrectangle)；ParametershdcinHandletothedevicecontext.nLeftRectinSpecifiesthelogicalx-coordinateoftheupper-leftcorneroftherectangle.nTopRectinSpecifiesthelogicaly-coordinateoftheupper-leftcorneroftherectangle.nRightRectinSpecifiesthelogicalx-coordinate

36、ofthelower-rightcorneroftherectangle.nBottomRectinSpecifiesthelogicaly-coordinateofthelower-rightcorneroftherectangle.CreateSolidBrushTheCreateSolidBrushfunctioncreatesalogicalbrushthathasthespecifiedsolidcolor.HBRUSHCreateSolidBrush(COLORREFcrColor/brushcolorvalue);ParameterscrColorinSpecifiestheco

37、lorofthebrush.TocreateaCOLORREFcolorvalue,usetheRGBmacro.CreatePenTheCreatePenfunctioncreatesalogicalpenthathasthespecifiedstyle,width,andcolor.Thepencansubsequentlybeselectedintoadevicecontextandusedtodrawlinesandcurves.HPENCreatePen(intfnPenStyle,/penstyleintnWidth,/penwidthCOLORREFcrColor/pencolo

38、r);ParametersfnPenStyleinSpecifiesthepenstyle.Itcanbeanyoneofthefollowingvalues.ValueMeaningPS_SOLIDThepenissolid.PS_DASHThepenisdashed.Thisstyleisvalidonlywhenthepenwidthisoneorlessindeviceunits.PS_DOTThepenisdotted.Thisstyleisvalidonlywhenthepenwidthisoneorlessindeviceunits.PS_DASHDOTThepenhasalte

39、rnatingdashesanddots.Thisstyleisvalidonlywhenthepenwidthisoneorlessindeviceunits.PS_DASHDOTDOTThepenhasalternatingdashesanddoubledots.Thisstyleisvalidonlywhenthepenwidthisoneorlessindeviceunits.PS_NULLThepenisinvisible.PS_INSIDEFRAMEThepenissolid.WhenthispenisusedinanyGDIdrawingfunctionthattakesabou

40、ndingrectangle,thedimensionsofthefigureareshrunksothatitfitsentirelyintheboundingrectangle,takingintoaccountthewidthofthepen.Thisappliesonlytogeometricpens.nWidthinSpecifiesthewidthofthepen,inlogicalunits.IfnWidthiszero,thepenisasinglepixelwide,regardlessofthecurrenttransformation.CreatePenreturnsap

41、enwiththespecifiedwidthbitwiththePS_SOLIDstyleifyouspecifyawidthgreaterthanoneforthefollowingstyles:PS_DASH,PS_DOT,PS_DASHDOT,PS_DASHDOTDOT.crColorinSpecifiesacolorreferenceforthepencolor.TogenerateaCOLORREFstructure,usetheRGBmacro.ReturnValuesIfthefunctionsucceeds,thereturnvalueisahandlethatidentif

42、iesalogicalpen.Ifthefunctionfails,thereturnvalueisNULL.GetLastErrorWindowsNT/2000:Togetextendederrorinformation,callRemarksAfteranapplicationcreatesalogicalpen,itcanselectthatpenintoadevicecontextbycallingtheSelectObjectfunction.Afterapenisselectedintoadevicecontext,itcanbeusedtodrawlinesandcurves.I

43、fthevaluespecifiedbythenWidthparameteriszero,alinedrawnwiththecreatedpenalwaysisasinglepixelwideregardlessofthecurrenttransformation.IfthevaluespecifiedbynWidthisgreaterthan1,thefnPenStyleparametermustbePS_NULL,PS_SOLID,orPS_INSIDEFRAME.IfthevaluespecifiedbynWidthisgreaterthan1andfnPenStyleisPS_INSI

44、DEFRAMEhelineassociatedwiththepenisdrawninsidetheframeofallprimitivesexceptpolygonsandpolylines.IfthevaluespecifiedbynWidthisgreaterthan1,fnPenStyleisPS_INSIDEFRAM同ndthecolorspecifiedbythecrColorparameterdoesnotmatchoneoftheentriesinthelogicalpalette,thesystemdrawslinesbyusingaditheredcolor.Dithered

45、colorsarenotavailablewithsolidpens.WhenyounoIongerneedthepen,calltheDeleteObjectfunctiontodeleteit.ShowCursorTheShowCShowCursor(BOOLbShow/cursorvisibility);ParametersbShowinSpecifieswhethertheinternaldisplaycounteristobeincrementedordecremented.IfbShowisTRUE,

46、thedisplaycountisincrementedbyone.IfbShowisFALSE,thedisplaycountisdecrementedbyone.ReturnValuesThereturnvaluespecifiesthenewdisplaycounter.RemarksThisfunctionsetsaninternaldisplaycounterthatdetermineswhetherthecursorshouldbedisplayed.Thecursorisdisplayedonlyifthedisplaycountisgreaterthanorequalto0.I

47、famouseisinstalled,theinitialdisplaycountis0.Ifnomouseisinstalled,thedisplaycountis-1.GetCursorPosTheGetCursorPosfunctionretrievesthecursorsposition,inscreencoordinates.BOOLGetCursorPos(LPPOINTlpPoint/cursorposition);ParameterslpPointoutPointertoaPOINTstructurethatreceivesthescreencoordinatesofthecu

48、rsor.ScreenToClientTheScreenToClientfunctionconvertsthescreencoordinatesofaspecifiedpointonthescreentoclientcoordinates.BOOLScreenToClient(HWNDhWnd/handletowindowLPPOINTlpPoint/screencoordinates);ParametershWndinHandletothewindowwhoseclientareawillbeusedfortheconversion.lpPointinPointertoaPOINTstruc

49、turethatspecifiesthescreencoordinatestobeconverted.ReturnValuesIfthefunctionsucceeds,thereturnvalueisnonzero.Ifthefunctionfails,thereturnvalueiszero.WindowsNT/2000:Togetextendederrorinformation,callGetLastErrorRemarksThefunctionusesthewindowidentifiedbythehWncparameterandthescreencoordinatesgivenint

50、hePOINTstructuretocomputeclientcoordinates.Itthenreplacesthescreencoordinateswiththeclientcoordinates.Thenewcoordinatesarerelativetotheupper-leftcornerofthespecifiedwindowsclientarea.TheScreenToClientfunctionassumesthespecifiedpointisinscreencoordinates.Allcoordinatesareindeviceunits.ClientToScreenT

51、heClientToScreenfunctionconvertstheclient-areacoordinatesofaspecifiedpointtoscreencoordinates.BOOLClientToScreen(HWNDhWnd/handletowindowLPPOINTlpPoint/screencoordinates)；ParametershWndinHandletothewindowwhoseclientareaisusedfortheconversion.lpPointin/outPointertoaPOINTstructurethatcontainstheclientc

52、oordinatestobeconverted.Thenewscreencoordinatesarecopiedintothisstructureifthefunctionsucceeds.ReturnValuesIfthefunctionsucceeds,thereturnvalueisnonzero.Ifthefunctionfails,thereturnvalueiszero.WindowsNT/2000:Togetextendederrorinformation,callGetLastErrorRemarksTheClientToScreenfunctionreplacesthecli

53、ent-areacoordinatesinthePOINTstructurewiththescreencoordinates.Thescreencoordinatesarerelativetotheupper-leftcornerofthescreen.Note,ascreen-coordinatepointthatisabovethewindowsclientareahasanegativey-coordinate.Similarly,ascreencoordinatetotheleftofaclientareahasanegativex-coordinate.Allcoordinatesa

54、redevicecoordinates.RequirementsSetCursorPosTheSetCursorPosfunctionmovesthecursortothespecifiedscreencoordinates.BOOLSetCursorPos(intX,/horizontalpositionintY/verticalposition);ParametersXinSpecifiesthenewx-coordinateofthecursor,inscreencoordinates.YinSpecifiesthenewy-coordinateofthecursor,inscreenc

55、oordinates.GetWindowLongTheGetWindowLongfunctionretrievesinformationaboutthespecifiedwindow.Thefunctionalsoretrievesthe32-bit(long)valueatthespecifiedoffsetintotheextrawindowmemory.Ifyouareretrievingapointerorahandle,thisfunctionhasbeensupersededbytheGetWindowLongPtrfunction.(Pointersandhandlesare32

56、bitson32-bitWindowsand64bitson64-bitWindows.)Towritecodethatiscompatiblewithboth32-bitand64-bitversionsofWindows,useGetWindowLongPtr.LONGGetWindowLong(HWNDhWnd/handletowindowintnlndex/offsetofvaluetoretrieve);ParametershWndinHandletothewindowand,indirectly,theclasstowhichthewindowbelongs.nlndexinSpecifiesthezero-basedoffsettothevaluetoberetrieved.Validvaluesareintherangezerothroughthenumberofbyteso