关于 Delphi 中流的使用(4) 遍历读取流中的所有数据

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Memo1: TMemo;
    Memo2: TMemo; {需要添加两个 Memo 用于显示}
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

//先制造一个测试文件
procedure TForm1.FormCreate(Sender: TObject);
var
  strList: TStringList;
begin
  strList := TStringList.Create;
  strList.Add('ABCDEFGHIJKLMNOPQRSTUVWXYZ');
  strList.SaveToFile('c:\temp\test.txt');
  strList.Free;
end;


procedure TForm1.Button1Click(Sender: TObject);
var
  ms: TMemoryStream;
  c: Char;
  s1,s2: string;
begin
  ms := TMemoryStream.Create;
  ms.LoadFromFile('c:\temp\test.txt'); {读入内存流}

  s1 := '';
  s2 := '';
  ms.Position := 0;                       {指针到开始}
  while ms.Position < ms.Size do          {循环读出; 应该写作 while ms.Read(c,1) > 0 do }
  begin
    ms.Read(c,1);                         {每读出一个字节, 指针会自动移到新的位置}
    s1 := s1 + c + ' ';                   {用文本记录}
    s2 := s2 + IntToHex(Byte(c),2) + ' '; {用两位数的十六进制记录}
  end;

  Memo1.Lines.Text := s1;
  Memo2.Lines.Text := s2;

  {Memo1 会显示: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z }
  {Memo2 会显示: 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F 50 51 52 53 54 55 56 57 58 59 5A 0D 0A}
  ms.Free;
end;

end.