把主调程序的变量传到DLL的窗体上.

Question

下面是我动态调用DLL的代码(测试过没问题),现在我想在不改动现有代码的情况下,加一个函数,把主调程序的S变量,传到DLL窗体上的label1.caption中. 
问题:根据下面代码,把新的传递函数加进去.(如能帮忙写出代码,不胜感激.先谢谢了.)主调代码: unit Unit1;  //主调程序 interface uses 
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, 
  Dialogs, StdCtrls; type 
tshowcalendar=function(ahandle:thandle;acaption:pchar):tdatetime;stdcall; 
  edllloaderror=class(exception); 
  Tmainform = class(TForm) 
    Button1: TButton; 
    Button2: TButton; 
    procedure Button1Click(Sender: TObject); 
    procedure Button2Click(Sender: TObject); 
  private 
    { Private declarations } 
  public 
    { Public declarations } 
  end; var 
  mainform: Tmainform; implementation {$R *.dfm} procedure Tmainform.Button1Click(Sender: TObject); 
var 
libhandle:thandle; 
showcalendar:tshowcalendar; 
s:STRING; 
begin 
libhandle:=loadlibrary('dll.dll'); 
try 
if libhandle=0 then 
  raise edllloaderror.Create('DLL不存在!'); 
  @showcalendar:=getprocaddress(libhandle,'showcalendar'); 
if not (@showcalendar=nil) then 
  showcalendar(application.MainForm.Handle,pchar(caption)) 
else 
  raiselastwin32error; 
finally 
freelibrary(libhandle); 
end; end; 
DLL窗体代码: unit dll_1; interface uses 
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, 
  Dialogs, StdCtrls; type 
  TdllForm = class(TForm) 
    Label1: TLabel; 
    procedure FormClose(Sender: TObject; var Action: TCloseAction); 
    procedure Label1Click(Sender: TObject); 
  private 
    { Private declarations } 
  public 
    { Public declarations } 
  end; var 
  dllform: Tdllform; function showcalendar(ahandle: thandle; acaption: PChar): tdatetime; stdcall; 
implementation {$R *.dfm} 
  function showcalendar(ahandle: thandle; acaption: PChar): tdatetime; stdcall; 
var 
  dllform: Tdllform; 
begin 
  application.Handle := ahandle; 
  dllform := tdllform.Create(application); 
  try 
    dllform.Caption := acaption; 
    dllform.ShowModal; 
    Result := Now; 
  finally 
    dllform.Free; 
  end; 
end; procedure TdllForm.FormClose(Sender: TObject; var Action: TCloseAction); 
begin 
Action:=caFree; 
end; 

Answer 1

就这工作量，你还不如改一下现有代码了，恕我直言，这代码写得真是不咋地。
全局变量dllform定义来有什么用？

Answer 2

主调代码: unit Unit1;  //主调程序 interface uses 
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, 
  Dialogs, StdCtrls; type 
tshowcalendar=function(ahandle:thandle;acaption:pchar):tdatetime;stdcall; 
TSetLabelCaption=procedure(s:pchar);stdcall; 
  edllloaderror=class(exception); 
  Tmainform = class(TForm) 
    Button1: TButton; 
    Button2: TButton; 
    procedure Button1Click(Sender: TObject); 
    procedure Button2Click(Sender: TObject); 
  private 
    { Private declarations } 
  public 
    { Public declarations } 
  end; var 
  mainform: Tmainform; implementation {$R *.dfm} procedure Tmainform.Button1Click(Sender: TObject); 
var 
libhandle:thandle; 
showcalendar:tshowcalendar; 
SetLabelCaption:TSetLabelCaption;
s:STRING; 
begin 
libhandle:=loadlibrary('dll.dll'); 
try 
if libhandle=0 then 
  raise edllloaderror.Create('DLL不存在!'); 
  @showcalendar:=getprocaddress(libhandle,'showcalendar'); 
if not (@showcalendar=nil) then 
  showcalendar(application.MainForm.Handle,pchar(caption)) 
else 
  raiselastwin32error;  @SetLabelCaption:=getprocaddress(libhandle,'SetLabelCaption');
if not (@showcalendar=nil) then 
  showcalendar(pchar(caption)) 
else 
  raiselastwin32error; finally 
freelibrary(libhandle); 
end; end; 
DLL窗体代码: unit dll_1; interface uses 
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, 
  Dialogs, StdCtrls; type 
  TdllForm = class(TForm) 
    Label1: TLabel; 
    procedure FormClose(Sender: TObject; var Action: TCloseAction); 
    procedure Label1Click(Sender: TObject); 
  private 
    { Private declarations } 
  public 
    { Public declarations } 
  end; var 
  dllform: Tdllform; function showcalendar(ahandle: thandle; acaption: PChar): tdatetime; stdcall; 
procedure SetLabelCaption(S:PChar);stdcall;
implementation {$R *.dfm} 
  function showcalendar(ahandle: thandle; acaption: PChar): tdatetime; stdcall;
var 
  dllform: Tdllform; 
begin 
  application.Handle := ahandle; 
  dllform := tdllform.Create(application); 
  try 
    dllform.Caption := acaption; 
    dllform.ShowModal; 
    Result := Now; 
  finally 
    dllform.Free; 
  end; 
end; procedure SetLabelCaption(S:PChar);stdcall;
begin 
   dllform.label1.caption := s;
end; 
procedure TdllForm.FormClose(Sender: TObject; var Action: TCloseAction); 
begin 
Action:=caFree; 
end; 

Answer 3

主调代码报错:
[Warning] Unit1.pas(46): Symbol 'RaiseLastWin32Error' is deprecated
[Error] Unit1.pas(50): Incompatible types: 'Cardinal' and 'PAnsiChar'
[Warning] Unit1.pas(52): Symbol 'RaiseLastWin32Error' is deprecated
[Fatal Error] Project1.dpr(5): Could not compile used unit 'Unit1.pas'unit Unit1;  //主调程序 interface uses 
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, 
  Dialogs, StdCtrls; type 
tshowcalendar=function(ahandle:thandle;acaption:pchar):tdatetime;stdcall; 
TSetLabelCaption=procedure(s:pchar);stdcall; 
  edllloaderror=class(exception); 
  Tmainform = class(TForm) 
    Button1: TButton; 
    Button2: TButton; 
    procedure Button1Click(Sender: TObject); 
    procedure Button2Click(Sender: TObject); 
  private 
    { Private declarations } 
  public 
    { Public declarations } 
  end; var 
  mainform: Tmainform; implementation {$R *.dfm} procedure Tmainform.Button1Click(Sender: TObject); 
var 
libhandle:thandle; 
showcalendar:tshowcalendar; 
SetLabelCaption:TSetLabelCaption; 
s:STRING; 
begin 
libhandle:=loadlibrary('dll.dll'); 
try 
if libhandle=0 then 
  raise edllloaderror.Create('DLL不存在!'); 
  @showcalendar:=getprocaddress(libhandle,'showcalendar'); 
if not (@showcalendar=nil) then 
  showcalendar(application.MainForm.Handle,pchar(caption)) 
else 
  raiselastwin32error; @SetLabelCaption:=getprocaddress(libhandle,'SetLabelCaption'); 
if not (@showcalendar=nil) then 
  showcalendar(pchar(caption)) 这里报错,是不是可以直接把caption换成我的A变量呀,要不要用那个函数转换?
else 
  raiselastwin32error; finally 
freelibrary(libhandle); 
end; end;