unit Unit1;interfaceuses  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,  Dialogs, StdCtrls;type  TForm1 = class(TForm)    Label1: TLabel;    Edit1: TEdit;    Edit2: TEdit;    Button1: TButton;    procedure Button1Click(Sender: TObject);  private    { Private declarations }  public    { Public declarations }  end;var  Form1: TForm1;implementation{$R *.dfm}type  epasswordinvalid = class(exception);procedure TForm1.Button1Click(Sender: TObject);var  gpassword: string;begin  if edit1.Text <> edit2.Text then    begin      raise epasswordinvalid.Create('由程序员显示异常信息' + #10 + #13 + '密码输入有误！');      edit2.Text := '';                         //此行永远不会被执行    end  else    begin      gpassword := edit1.Text;      showmessage('密码设定完成');    end;  showmessage('欢迎光临！');                    //前面不产生异常时，此行才会执行end;end.