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;
    Button4: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

uses IOUtils, Types;

const path = 'C:\Program Files\Embarcadero\RAD Studio\7.0';

//准备给 TDirectory.GetFiles 调用的函数, 须符合 TDirectory.TFilterPredicate 格式
function fp(const Path: string; const SearchRec: TSearchRec): Boolean;
begin
  Form1.Memo1.Lines.Add(Path + '\' + SearchRec.Name);
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  files: TStringDynArray;
begin
  Memo1.Clear;
  files := TDirectory.GetFiles(path, fp);
end;

procedure TForm1.Button2Click(Sender: TObject);
var
  files: TStringDynArray;
begin
  Memo1.Clear;
  files := TDirectory.GetFiles(path, '*.txt', fp);
end;

procedure TForm1.Button3Click(Sender: TObject);
var
  files: TStringDynArray;
begin
  Memo1.Clear;
  files := TDirectory.GetFiles(path, '*.txt', TSearchOption.soAllDirectories, fp);
end;

//可以这样方便地使用匿名函数
procedure TForm1.Button4Click(Sender: TObject);
var
  files: TStringDynArray;
begin
  Memo1.Clear;
  files := TDirectory.GetFiles(path,
    function(const Path: string; const SearchRec: TSearchRec): Boolean
    begin
      Memo1.Lines.Add(Path + '\' + SearchRec.Name);
    end
  );
end;

end.