WinAPI 字符及字符串函数(1): CharLower - 字符或字符串转小写

unit Unit1;



interface



uses

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

  Dialogs, 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);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



{对字符}

procedure TForm1.Button1Click(Sender: TObject);

var

  C: Char;

begin

  C := 'A';

  C := Char(CharLower(PChar(C)));

  ShowMessage(C); {a}

end;



{对字符常量}

procedure TForm1.Button2Click(Sender: TObject);

var

  C: Char;

begin

  C := Char(CharLower(PChar('A')));

  ShowMessage(C); {a}

end;



{对字符数组}

procedure TForm1.Button3Click(Sender: TObject);

var

  Arr: array[0..2+1] of Char;

begin

  Arr := 'ABC';

  CharLower(Arr);

  ShowMessage(Arr); {abc}

end;



{对字符串}

procedure TForm1.Button4Click(Sender: TObject);

var

  str: string;

begin

  str := 'ABC';

  CharLower(@str[1]);

  ShowMessage(str); {abc}

end;



{Delphi 的 SysUtils.LowerCase}

procedure TForm1.Button5Click(Sender: TObject);

var

  str: string;

begin

  str := 'ABC';

  str := LowerCase(str);

  ShowMessage(str); {abc}

end;



end.