再问如何用Delphi运行DOS命令

Question

unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs,shellapi, StdCtrls;type
  TForm1 = class(TForm)
    Edit1: TEdit;
    Memo1: TMemo;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;var
  Form1: TForm1;implementation{$R *.dfm}procedure TForm1.Button1Click(Sender: TObject);
begin
  ShellExecute(handle,'open','cmd.exe',' /k "dir edit1.text > c:\ao.txt"','',SW_HIDE);  Memo1.Lines.LoadFromFile('c:\ao.txt');
end;end.
为什么有时提示错误找不到文件,而提示错误后再运行一次MEMO1就显示
驱动器D的卷是SOFT
卷的序列号是3F14-01C3
D:\Program Files\Borland\Delphi7\Projects 的目录

Answer 1

WinExec(PChar(Format('dir %s > c:\ao.txt', [Edit1.text])), SW_HIDE);

Answer 2

var
 Command:string;
begin
 Command:='COMMAND.COM /C dir>c:\dir.txt';
 WinExec(pchar(Command), sw_shownormal);
end;