unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    Button4: TButton;
    Button5: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
    procedure Button5Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var s: Widestring;
begin
s := '桂枝香在故国晚秋';
ShowMessage(IntToStr(Length(String(s))));//XE显示8   //D7 结果不是8而是16
end;

procedure TForm1.Button2Click(Sender: TObject);
var s: Widestring;
begin
s := '桂枝香在故国晚秋';
ShowMessage(IntToStr(Length(s))); //XE显示8  //D7结果不是16而是8
end;

procedure TForm1.Button3Click(Sender: TObject);
var
  s: AnsiString;
begin
  s:='桂枝香在故国晚秋';
  ShowMessage(IntToStr(Length(s)));  //XE显示16
end;

procedure TForm1.Button4Click(Sender: TObject);
var
  s: AnsiString;
begin
  s:='桂枝香在故国晚秋';
  ShowMessage(IntToStr(strlen(PWideChar(s)))); //XE显示8
end;

procedure TForm1.Button5Click(Sender: TObject);
var
  s: AnsiString;
begin
  s:='桂枝香在故国晚秋';
  ShowMessage(IntToStr(SizeOf(PWideChar(s)))); //XE显示4(32位程序)
end;

end.