案例2：可擴(kuò)展的對(duì)話(huà)框2023/4/221需求與目標(biāo)這個(gè)功能類(lèi)似QQ的顯示聊天記錄當(dāng)用戶(hù)要顯示一些過(guò)多的選擇時(shí)，對(duì)話(huà)框自動(dòng)擴(kuò)展其大小，將隱藏的部分顯示出來(lái)2023/4/222效果2023/4/223效果2023/4/224手段利用CDialog類(lèi)的SetRect函數(shù)來(lái)設(shè)定對(duì)話(huà)框的大小2023/4/225手段利用CDialog類(lèi)的SetRect函數(shù)來(lái)設(shè)定對(duì)話(huà)框的大小調(diào)用MoveWindow函數(shù)來(lái)實(shí)現(xiàn)改變對(duì)話(huà)框的大小2023/4/226編程步驟（1）使用AppWizard創(chuàng)建一個(gè)基于對(duì)話(huà)框的應(yīng)用程序2023/4/227編程步驟（2）為對(duì)話(huà)框添加一些控件2023/4/228編程步驟（2）2023/4/229編程步驟（2）2023/4/2210編程步驟（3）為對(duì)話(huà)框添加3個(gè)成員變量：BOOLm_bExpand;//記錄是否已經(jīng)擴(kuò)展對(duì)話(huà)框UINTm_nExpandedHeight;//擴(kuò)展后對(duì)話(huà)框的高度UINTm_nNormalHeight;//擴(kuò)展前對(duì)話(huà)框的高度2023/4/2211BOOLtypedefintBOOL;typedeflongBOOL;ABooleanvalue.

2023/4/2212UINT

typedefunsignedintUINT;A16-bitunsignedintegeronWindowsversions3.0and3.1;a32-bitunsignedintegeronWin32.

2023/4/2213編程步驟（4）在對(duì)話(huà)框的OnInitDialog函數(shù)中加入以下代碼： 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);2023/4/2214CWnd::GetWindowRectvoid

GetWindowRect(

LPRECT

lpRect

)

const;

lpRectPointstoaCRectobjectoraRECTstructurethatwillreceivethescreencoordinatesoftheupper-leftandlower-rightcorners.RemarksCopiesthedimensionsoftheboundingrectangleoftheCWndobjecttothestructurepointedtobylpRect.Thedimensionsaregiveninscreencoordinatesrelativetotheupper-leftcornerofthedisplayscreen.Thedimensionsofthecaption,border,andscrollbars,ifpresent,areincluded.2023/4/2215RECT、LPRECTtypedefstructtagRECT{LONGleft;LONGtop;LONGright;LONGbottom;}RECT,*PRECT,NEAR*NPRECT,FAR*LPRECT;2023/4/2216CRectclassCRect:publictagRECT{public:…… //retrievesthewidth intWidth()const; //returnstheheight intHeight()const;……}2023/4/2217CWnd::GetDlgItem

CWnd*

GetDlgItem(

int

nID

)

const;nIDSpecifiestheidentifierofthecontrolorchildwindowtoberetrieved.ReturnValueApointertothegivencontrolorchildwindow.IfnocontrolwiththeintegerIDgivenbythenIDparameterexists,thevalueisNULL.Thereturnedpointermaybetemporaryandshouldnotbestoredforlateruse.RemarksRetrievesapointertothespecifiedcontrolorchildwindowinadialogboxorotherwindow.ThepointerreturnedisusuallycasttothetypeofcontrolidentifiedbynID.2023/4/2218控件IDresource.h#defineIDC_BORDER1000#defineIDC_EXPAND10012023/4/2219CRect::SetRectvoid

SetRect(

int

x1,

int

y1,

int

x2,

int

y2

);x1Specifiesthex-coordinateoftheupper-leftcorner.y1Specifiesthey-coordinateoftheupper-leftcorner.x2Specifiesthex-coordinateofthelower-rightcorner.y2Specifiesthey-coordinateofthelower-rightcorner.RemarksSetsthedimensionsofCRecttothespecifiedcoordinates.2023/4/2220CWnd::MoveWindowvoid

MoveWindow(

LPCRECT

lpRect,BOOL

bRepaint=TRUE

);lpRectTheCRectobjectorRECTstructurethatspecifiesthenewsizeandposition.bRepaintSpecifieswhetherCWndistoberepainted.RemarksChangesthepositionanddimensions.Foratop-levelCWndobject,thexandyparametersarerelativetotheupper-leftcornerofthescreen.ForachildCWndobject,theyarerelativetotheupper-leftcorneroftheparentwindow’sclientarea.2023/4/2221編程步驟（5）為“隱藏”按鈕添加單擊響應(yīng)函數(shù)OnExpand：2023/4/2222編程步驟（5）為“隱藏”按鈕添加單擊響應(yīng)函數(shù)OnExpand：voidCExpandDlgDlg::OnExpand(){ m_bExpand=!m_bExpand;

CRectrcDlg; GetWindowRect(rcDlg);2023/4/2223編程步驟（5） if(m_bExpand) { rcDlg.SetRect(rcDlg.left,rcDlg.top,rcDlg.left+rcDlg.Width(),rcDlg.top+m_nExpandedHeight); m_expand.SetWindowText("隱藏"); } else { rcDlg.SetRect(rcDlg.left,rcDlg.top,rcDlg.left+rcDlg.Width(),rcDlg.top+m_nNormalHeight); m_expand.SetWindowText("顯示"); } MoveWindow(rcDlg,TRUE);}2023/4/2224CWnd::SetWindowTextvoid

SetWindowText(

LPCTSTR

lpszString

);lpszStringPointstoaCStringobjectornull-terminatedstringtobeusedasthenewtitleorcontroltext.RemarksSetsthewindo