文件预览程序源代码

■编程实现文献预览————————————————下列为程序代码—————————————TXTDLGTEMPLATEDIALOG0,0,316,76STYLE0x404L|WS_CHILD|WS_VISIBLE|WS_CLIPSIBLINGSFONT8,"MSSansSerif"{LTEXT"",1119,0,0,204,76,SS_LEFT|WS_CHILD|NOTWS_VISIBLE|WS_GROUP}————————————————————————————————unittxtDialog;interfaceusesWindows,Messages,SysUtils,Classes,StdCtrls,ExtCtrls,Buttons,Dialogs,ShellAPI,Controls;typeTtxtDialog=class(TOpenDialog)private{Privatedeclarations}FtxtPanel:TPanel;FtxtLabel:TLabel;FPreviewButton:TSpeedButton;FtxtCtrl:TMemo;protected{Protecteddeclarations}procedurePreviewClick(Sender:TObject);virtual;procedureDoSelectionChange;override;procedureDoShow;override;propertytxtCtrl:TMemoreadFtxtCtrl;public{Publicdeclarations}constructorCreate(AOwner:TComponent);override;functionExecute:Boolean;override;published{Publisheddeclarations}end;implementation{$RtxtDialog.res}{TtxtDialog}constructorTtxtDialog.Create(AOwner:TComponent);begininheritedCreate(AOwner);//文献扩展名过滤器Filter:='文本文献(*.txt)|*.txt';//定义一种主Panel---FtxtPanel，其它全部的构件都建立在这个Panel上FtxtPanel:=TPanel.Create(Self);withFtxtPaneldobeginName:='txtPanel';Caption:='';SetBounds(204,5,169,200);BevelOuter:=bvNone;BorderWidth:=2;TabOrder:=1;FtxtLabel:=TLabel.Create(Self);withFtxtLabeldobeginName:='txtLabel';Caption:='文本文献预览';Font.Charset:=GB2312_CHARSET;Font.Name:='宋体';Font.Size:=9;SetBounds(6,6,157,23);Align:=alTop;AutoSize:=False;Parent:=FtxtPanel;end;//文献预览按钮FPreviewButton:=TSpeedButton.Create(Self);withFPreviewButtondobeginName:='PreviewButton';SetBounds(77,1,23,22);Enabled:=False;//从资源文献中读出TXTGLYPH图像，用于SpeedButton的图像Glyph.LoadFromResourceName(HInstance,'TXTGLYPH');Hint:='查看该文献';ParentShowHint:=False;ShowHint:=True;//OnClick事件，调用记事本打开该文本文献OnClick:=PreviewClick;Parent:=FtxtPanel;end;//添加一种Memo元件，用于显示文献内容FtxtCtrl:=TMemo.Create(Self);withFtxtCtrldobeginName:='Memo';SetBounds(6,29,157,145);Align:=alClient;//OnDblClick事件OnDblClick:=PreviewClick;TabOrder:=2;ReadOnly:=True;Text:='';ScrollBars:=ssBoth;Parent:=FtxtPanel;end;end;end;procedureTtxtDialog.DoSelectionChange;varValided:Boolean;f:TextFile;s:string;functionValidFile(constFileName:string):Boolean;beginResult:=GetFileAttributes(PChar(FileName))<>$FFFFFFFF;end;beginFtxtCtrl.Lines.Clear;Valided:=FileExists(FileName)andValidFile(FileName)and(UpperCase(ExtractFileExt(Filename))='.TXT');ifValidedthentry//打开文献，逐行读入Memo的Lines，完毕预览AssignFile(f,Filename);FileMode:=fmOpenRead;Reset(f);whilenotEOF(f)dobeginReadln(f,s);FtxtCtrl.Lines.Add(s);end;CloseFile(f);FPreviewButton.Enabled:=True;exceptValided:=False;end;ifnotValidedthenFPreviewButton.Enabled:=False;inheritedDoSelectionChange;end;procedureTtxtDialog.DoShow;varPreviewRect,StaticRect:TRect;begin//GetClientRect是WindowsAPI，求出了整个Client区的大小GetClientRect(Handle,PreviewRect);//GetStaticRect是TOpenDialog提供的办法，求出了原则区的大小StaticRect:=GetStaticRect;//将PreviewRect缩小在StaticRect的右边//应当使用PreviewRect.Left:=StaticRect.Right，此处保存了ExtDlgs.pas中语句PreviewRect.Left:=StaticRect.Left+(StaticRect.Right-StaticRect.Left);Inc(PreviewRect.Top,4);//添加预览内容FtxtPanel.BoundsRect:=PreviewRect;FPreviewButton.Left:=FtxtCtrl.BoundsRect.Right-FPreviewButton.Width-2;FtxtPanel.ParentWindow:=Handle;inheritedDoShow;end;functionTtxtDialog.Execute:Boolean;begin//传递自定义对话框TXTDLGTEMPLATEifNewStyleControlsandnot(ofOldStyleDialoginOptions)thenTemplate:='TXTDLGTEMPLATE'elseTemplate:=nil;Result:=inheritedExecute;end;procedureTtxtDialog.PreviewClick(Sender:TObject);begin//使用记事本打开该文本文献ifUpperCase(ExtractFileExt(Filename))='.TXT't