delphi的流 遍历内存流

源代码：
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unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Memo1: TMemo;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;

    { Public declarations }
  end;

var
  Form1: TForm1;
  fpath:string;
  mStream:TMemoryStream;

implementation

{$R *.dfm}
{$APPTYPE CONSOLE}

//遍历流
procedure TForm1.Button1Click(Sender: TObject);
var
  i:integer;
  str:string;
  c:char;
begin
  mStream.LoadFromFile(fpath);
  mStream.Position:=0;
  while mStream.Position  begin
    mStream.Read(c,1);
    writeln(c);
    str:=str+c+' ';
  end;
  memo1.Text:=str;
end;

constructor TForm1.Create(AOwner: TComponent);
var
  strList:TStringList;
begin
  inherited;
  strList:=TStringList.Create;
  fpath:=ExtractFilePath(Application.ExeName)+'test.txt';
  strList.Add('abcdefghijklmnopqrst');
  strList.SaveToFile(fpath);
  mStream:=TMemoryStream.Create;
end;

destructor TForm1.Destroy;
begin
  mStream.Free;
  inherited;
end;

end.