unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Memo1: TMemo;
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

uses IOUtils, Types;

{这是随意拿来的测试路径}
const path = 'C:\Program Files\Embarcadero\RAD Studio\7.0';

//获取指定目录下的所有文件
procedure TForm1.Button1Click(Sender: TObject);
var
  dir: TDirectory; {这是个结构, 后面就不再声明了, 将直接使用}
  files: TStringDynArray; {TStringDynArray = array of string;}
  str: string;
begin
  files := dir.GetFiles(path);
  Memo1.Clear;
  for str in files do Memo1.Lines.Add(str);
end;

//获取指定目录下的所有指定类型的文件
procedure TForm1.Button2Click(Sender: TObject);
var
  files: TStringDynArray;
  str: string;
begin
  files := TDirectory.GetFiles(path, '*.txt');
  Memo1.Clear;
  for str in files do Memo1.Lines.Add(str);
end;

//获取指定目录及其嵌套目录下的所有指定类型的文件
procedure TForm1.Button3Click(Sender: TObject);
var
  files: TStringDynArray;
  str: string;
begin
  files := TDirectory.GetFiles(path, '*.txt', TSearchOption.soAllDirectories);
  Memo1.Clear;
  for str in files do Memo1.Lines.Add(str);
end;

end.