案例2：可扩展的对话框ppt课件

案例2：可扩展的对话框,1,需求与目标,这个功能类似QQ的显示聊天记录当用户要显示一些过多的选择时，对话框自动扩展其大小，将隐藏的部分显示出来,2,效果,3,效果,4,手段,利用CDialog类的SetRect函数来设定对话框的大小,5,手段,利用CDialog类的SetRect函数来设定对话框的大小调用MoveWindow函数来实现改变对话框的大小,6,编程步骤（1）,使用AppWizard创建一个基于对话框的应用程序,7,编程步骤（2）,为对话框添加一些控件,8,编程步骤（2）,9,编程步骤（2）,10,编程步骤（3）,为对话框添加3个成员变量：BOOLm_bExpand;/记录是否已经扩展对话框UINTm_nExpandedHeight;/扩展后对话框的高度UINTm_nNormalHeight;/扩展前对话框的高度,11,BOOL,typedefintBOOL;typedeflongBOOL;ABooleanvalue.,12,UINT,typedefunsignedintUINT;A16-bitunsignedintegeronWindowsversions3.0and3.1;a32-bitunsignedintegeronWin32.,13,编程步骤（4）,在对话框的OnInitDialog函数中加入以下代码：m_bExpand=FALSE;CRectrcDlg,rcMarker;GetWindowRect(rcDlg);m_nExpandedHeight=rcDlg.Height();GetDlgItem(IDC_BORDER)-GetWindowRect(rcMarker);m_nNormalHeight=(rcMarker.top-rcDlg.top);rcDlg.SetRect(rcDlg.left,rcDlg.top,rcDlg.left+rcDlg.Width(),rcDlg.top+m_nNormalHeight);MoveWindow(rcDlg,TRUE);,14,CWnd:GetWindowRect,voidGetWindowRect(LPRECTlpRect)const;lpRectPointstoaCRectobjectoraRECTstructurethatwillreceivethescreencoordinatesoftheupper-leftandlower-rightcorners.RemarksCopiesthedimensionsoftheboundingrectangleoftheCWndobjecttothestructurepointedtobylpRect.Thedimensionsaregiveninscreencoordinatesrelativetotheupper-leftcornerofthedisplayscreen.Thedimensionsofthecaption,border,andscrollbars,ifpresent,areincluded.,15,RECT、LPRECT,typedefstructtagRECTLONGleft;LONGtop;LONGright;LONGbottom;RECT,*PRECT,NEAR*NPRECT,FAR*LPRECT;,16,CRect,classCRect:publictagRECTpublic:/retrievesthewidthintWidth()const;/returnstheheightintHeight()const;,17,CWnd:GetDlgItem,CWnd*GetDlgItem(intnID)const;nIDSpecifiestheidentifierofthecontrolorchildwindowtoberetrieved.ReturnValueApointertothegivencontrolorchildwindow.IfnocontrolwiththeintegerIDgivenbythenIDparameterexists,thevalueisNULL.Thereturnedpointermaybetemporaryandshouldnotbestoredforlateruse.RemarksRetrievesapointertothespecifiedcontrolorchildwindowinadialogboxorotherwindow.ThepointerreturnedisusuallycasttothetypeofcontrolidentifiedbynID.,18,控件ID,resource.h#defineIDC_BORDER1000#defineIDC_EXPAND1001,19,CRect:SetRect,voidSetRect(intx1,inty1,intx2,inty2);x1Specifiesthex-coordinateoftheupper-leftcorner.y1Specifiesthey-coordinateoftheupper-leftcorner.x2Specifiesthex-coordinateofthelower-rightcorner.y2Specifiesthey-coordinateofthelower-rightcorner.RemarksSetsthedimensionsofCRecttothespecifiedcoordinates.,20,CWnd:MoveWindow,voidMoveWindow(LPCRECTlpRect,BOOLbRepaint=TRUE);lpRectTheCRectobjectorRECTstructurethatspecifiesthenewsizeandposition.bRepaintSpecifieswhetherCWndistoberepainted.RemarksChangesthepositionanddimensions.Foratop-levelCWndobject,thexandyparametersarerelativetotheupper-leftcornerofthescreen.ForachildCWndobject,theyarerelativetotheupper-leftcorneroftheparentwindowsclientarea.,21,编程步骤（5）,为“隐藏”按钮添加单击响应函数OnExpand：,22,编程步骤（5）,为“隐藏”按钮添加单击响应函数OnExpand：voidCExpandDlgDlg:OnExpand()m_bExpand=!m_bExpand;CRectrcDlg;GetWindowRect(rcDlg);,23,编程步骤（5）,if(m_bExpand)rcDlg.SetRect(rcDlg.left,rcDlg.top,rcDlg.left+rcDlg.Width(),rcDlg.top+m_nExpandedHeight);m_expand.SetWindowText(隐藏);elsercDlg.SetRect(rcDlg.left,rcDlg.top,rcDlg.left+rcDlg.Width(),rcDlg.top+m_nNormalHeight);m_expand.SetWindowText(显示);MoveWindow(rcDlg,TRUE);,24,CWnd:SetWindowText,voidSetWindowText(LPCTSTRlpszString);lpszStringPointstoaCStringobjectornull-terminatedstringtobeusedasthenewtitleorcontroltext.RemarksSets