问题：异常类和自定义异常类构造函数的实现代码写在程序的什么部位？

Question

问题：异常类和自定义异常类构造函数的实现代码写在程序的什么部位？

Answer 1

unit test;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;type
  TForm1 = class(TForm)
    Label1: TLabel;
    Edit1: TEdit;
    Label2: TLabel;
    Edit2: TEdit;  //  einvalidation =class(exception)
  //  einvalidpassword =class(einvalidation)
  // einvalidinput =class(einvalidation)
    procedure passwordkeypress(sender:tobject;var key:char);
    procedure inputeditkeypress(sender:tobject;var key:char);
 private
    { Private declarations }
 public
 // errorcode:integer;
  //constructor create(const msg:string;errornum:integer);
//  constructor create;
//  constructor create(errornum:intger);
    { Public declarations }
  end;var
  Form1: TForm1;
implementation{$R *.dfm}type
einvalidation =class(exception)
public
errorcode:integer;
constructor create(const msg:string;errornum:integer);
end;einvalidpassword =class(einvalidation)
public
   constructor create;
   end;einvalidinput =class(einvalidation)
public
  constructor create(errornum:integer);
end;constructor einvalidation.create(const msg:string;errornum:integer);
begin
inherited create(msg);
errorcode:=errornum;
end;constructor einvalidpassword.create;
begin
inherited create('invalid password enter',0);
end;constructor einvalidinput.create(errornum:integer);
var
msg:string;
begin
case errornum of
1:
msg:='11111111';
2:
msg:='22222222';
else
msg:='33333';
end;
inherited create(msg,errornum);
end;
procedure tform1.passwordkeypress(sender:tobject;var key:char);
  const
    currentpassword='delphi';
    begin
    if key=#13 then
    begin
     try
       if password.text<>currentpassword then
       raise einvalidpassword.create;
       label2.visibel:=true;
       inputedit.visible:=true;
       inputedit.setfocus;
       password.visible:=false;
       label1.visible:=false;
       except
        on einvalidpassword do
        begin
        password.text:='';
        raise;
        end;
        end;
        key:=#0;
        end;
        end; 
 procedure tform1.inputeditkeypress(sender:tobject;var key:char);
 var
 res:real;
 code:integer;
 begin
 if key=#13 then
 begin
 try
 val(inputedit.text,res,code);
 if code<>0 then
 raise einvalidinput.create(1); if (res>1) or (res<0) then
 raise einvalidinput.create(2);
 messagedlg('correct input',mtinformation,[mbok],0);
 key:=#0;
 except
 on e:envalidinput do
 begin
 inputedit.text:='';
 messagedlg(e.message,mtwarning,[mbok],0);
 end;
 end;
 end;
end;
end.
这段程序错哪了？

Answer 2

已经调试可以运行了，但是不论在password里面输入什么，回车都没反映。怎么回事呢？
unit test;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;type
  TForm1 = class(TForm)
    Label1: TLabel;
    password: TEdit;
    Label2: TLabel;
    inputedit: TEdit;
    Button1: TButton;  procedure passwordkeypress(sender:tobject;var key:char);
  procedure inputeditkeypress(sender:tobject;var key:char);
  procedure Button1Click(Sender: TObject);
 private
    { Private declarations }
 public
    { Public declarations }
  end;var
  Form1: TForm1;
implementation{$R *.dfm}type
    einvalidation =class(exception)
public
errorcode:integer;
constructor create(const msg:string;errornum:integer);
end;einvalidpassword =class(einvalidation)
public
   constructor create;
   end;einvalidinput =class(einvalidation)
public
  constructor create(errornum:integer);
end;constructor einvalidation.create(const msg:string;errornum:integer);
begin
inherited create(msg);
errorcode:=errornum;
end;constructor einvalidpassword.create;
begin
inherited create('invalid password enter',0);
end;constructor einvalidinput.create(errornum:integer);
var
msg:string;
begin
case errornum of
1:
msg:='11111111';
2:
msg:='22222222';
else
msg:='33333';
end;
inherited create(msg,errornum);
end;
procedure tform1.passwordkeypress(sender:tobject;var key:char);
  const
    currentpassword='delphi';
    begin
    if key=#13 then
    begin
     try
       if password.text<>currentpassword then
       raise einvalidpassword.create;
       label2.visible:=true;
       inputedit.visible:=true;
       inputedit.setfocus;
       password.visible:=false;
       label1.visible:=false;
       except
        on einvalidpassword do
        begin
        password.text:='';
        raise;
        end;
        end;
        key:=#0;
        end;
        end; 
 procedure tform1.inputeditkeypress(sender:tobject;var key:char);
 var
 res:real;
 code:integer;
 begin
 if key=#13 then
 begin
 try
 val(inputedit.text,res,code);
 if code<>0 then
 raise einvalidinput.create(1); if (res>1) or (res<0) then
 raise einvalidinput.create(2);
 messagedlg('correct input',mtinformation,[mbok],0);
 key:=#0;
 except
 on e:einvalidinput do
 begin
 inputedit.text:='';
 messagedlg(e.message,mtwarning,[mbok],0);
 end;
 end;
 end;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
close
end;end.