Delphi 2009 之 TStringBuilder 类[5]: Chars[] 属性与 CopyTo 方法

unit Unit1;



interface



uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, StdCtrls;



type

  TForm1 = class(TForm)

    Button1: TButton;

    Button2: TButton;

    procedure Button1Click(Sender: TObject);

    procedure Button2Click(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



//TStringBuilder.CopyTo

procedure TForm1.Button1Click(Sender: TObject);

var

  sb: TStringBuilder;

  arr: TCharArray;

  i: Integer;

begin

  sb := TStringBuilder.Create;

  sb.Append('123456789');



  SetLength(arr, 9);

  for i := Low(arr) to High(arr) do arr[i] := '*';



  sb.CopyTo(3, arr, 1, 5);

  ShowMessage(PChar(arr));   {*45678***}



  sb.Free;

end;



//TStringBuilder.Chars

procedure TForm1.Button2Click(Sender: TObject);

var

  sb: TStringBuilder;

begin

  sb := TStringBuilder.Create('Delphi 2009');



  ShowMessage(sb.Chars[0]);             {D}

  ShowMessage(sb.Chars[sb.Length - 1]); {9}



  sb.Free;

end;



end.