处理之文本文件

 1 unit Unit1;

 2 

 3 interface

 4 

 5 uses

 6   Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

 7   Dialogs, StdCtrls;

 8 

 9 type

10   TForm1 = class(TForm)

11     Button1: TButton;

12     Button2: TButton;

13     Button3: TButton;

14     procedure Button1Click(Sender: TObject);

15     procedure Button2Click(Sender: TObject);

16     procedure Button3Click(Sender: TObject);

17   private

18     { Private declarations }

19   public

20     { Public declarations }

21   end;

22 

23 var

24   Form1: TForm1;

25 

26 implementation

27 

28 var

29   F: TextFile;

30   FileName: string = 'c:/A.txt';

31 

32 

33 {$R *.dfm}

34 

35 //向文本文件写入内容

36 procedure TForm1.Button1Click(Sender: TObject);

37 begin

38   AssignFile(F,FileName);

39   Rewrite(F);        //重写(覆盖)已存在的文件

40   Writeln(F,'one');  //写入一行

41   Writeln(F,'two');

42   CloseFile(F);

43 end;

44 

45 //读取文本文件内容

46 procedure TForm1.Button2Click(Sender: TObject);

47 var

48   str:string;

49 begin

50   AssignFile(F,FileName);

51   Reset(F);         //以只读方式打开文本文件

52   while not Eof(F) do      //循环文本文件,判断是否到尾部

53   begin

54     Readln(F,str);         //读取一行

55     ShowMessage(str);

56   end;

57 end;

58 

59 //向文本文件追加内容

60 procedure TForm1.Button3Click(Sender: TObject);

61 begin

62   AssignFile(F,FileName);

63   Append(F);              //打开文件准备追加,指针指向文本末尾

64   Writeln(F, 'three');   //写入一行

65   Writeln(F, 'four');

66   CloseFile(F);

67 end;

68 

69 end.

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