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.