dll调用子窗体内存释放问题急！

Question

library Project1;
uses
  SysUtils,
  windows,
  messages,
  controls,
  forms,
  dialogs,
  graphics,
  Classes,
  Unit1 in 'Unit1.pas' {Form1};{$R *.RES}
   var dllapplication :tapplication;
     dllproc:pointer; procedure provachild(parentapplication:tapplication;parentform:tform);export;stdcall;
 var form1:tform1;  begin
  application:=parentapplication;
  form1:=tform1.Create(parentform);
  form1.myparentapplication:=parentapplication;
  form1.myparentform:=parentform;
  windows.SetParent(form1.handle,parentform.handle);
  form1.FormStyle:=fsmdichild;
  form1.Show;  end;
 procedure dllunloadproc(reason:integer);register;
 begin
 if reason=DLL_PROCESS_DETACH then
 application:=dllapplication;
 end; exports
 provachild;
  begin
 // dllapplication:=application;
 // dllproc:=@dllunloadproc;
end.
mdi 子窗体
 
unit1;
public
   myparentapplication:tapplication;
   myparentform:tform;
    { Public declarations }
  end;
var
  Form1: TForm1;implementation{$R *.DFM}procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
application.Handle:=0;
action:=caFree ;end;
 调用代码 
procedure TForm1.Button1Click(Sender: TObject);
 var
proaddr:farproc;
provachild:T_provachlid;begin
 
 dllhandle:=loadlibrary('Project1.dll');
 @provachild:=getprocaddress(dllhandle,'provachild');
 if @provachild<>nil then
 provachild(application,self); end;procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin    while dllhandle<>0 do
    FreeLibrary(dllhandle);
    close;
     end;procedure TForm1.FormCreate(Sender: TObject);
begin
  dllhandle:=0;
end;
1： 程关闭时，按 ctrl+alt+delete 看，程序还存在啊，
2：mdi的application 关闭时，是否释放，怎样释放

Answer 1

exports 
provachild;
begin
  dllapplication:=application;
  dllproc:=@dllunloadproc;
  //去掉这里的注释
end.

Answer 2

我现在做的项目就采用楼主的模式，所有的功能都封装在一个个DLL中，同样也存在DLL库MDI子窗体释放的问题，这个问题从项目开始到现在快半年啦，眼看项目都要结束这个问题还没得到解决，真是寝食不安，CSDN经常有人说自己是高手，如果那写所谓的高手能给我解决这个难题，我一定开贴重酬！

Answer 3

zdy0155 () 程序写的什么呀！to Liusp:
这种模式很常用的，但动态加载功能dll是不可取的，
静态是很简单的。主程序有一个主窗口，各个功能用dll来实现，dll中可能会有子窗口
我不知道你具体用的什么方式。我说一下我们以前一个程序的处理方式，1.
dll中提供一个函数，用来创建子窗口，假设子窗口类名为TGIS02F01
函数名为GIS02F01_Open;
procedure GIS02F01_Open(var Form: TForm; Parameter: string);
begin
  Form := TGIS02F01.Create(nil);
  Form.WindowState:= ...;
end;子窗口关闭的时候用action:= caFree;2.
在主窗口中点击相应的菜单时，调用GIS02F01_Open就行了；
子窗口在关闭后是可以释放的

Answer 4

library dlldb;uses
  Windows,
  Forms in 'forms.pas',
  udll in 'udll.pas' {dll_Frm},
  umainformsVar in 'umainformsVar.pas';{}
{Function: Load the child Form
 Returns : FormVariable
 Par0: Application var off ExeFile
 Par1: CallBack procedure pointer to inform exefile of unloaded (freed)
       Form
}
function ShowChild(App:TApplication;PFormFreeCallBack:Pointer):TForm;stdcall; export;
begin
  Application:=App;
  Result:=TDll_Frm.Create(Application);
  @FormFreeCallBack:=PFormFreeCallBack;
end;
{Function: Set Dll-Application Var back to originall Value
}
procedure SetOldApplication;stdcall;export;
begin
  Application:=OldApp;
end;
{$R *.RES}
  exports ShowChild,SetOldApplication;
begin
  {Save original Applicatioin Variable}
  OldApp:=Application;
end.unit udll;interfaceuses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls;type
  Tdll_Frm = class(TForm)
    Memo1: TMemo;
    procedure FormDestroy(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
  private
    { Private-Deklarationen }
  public
    { Public-Deklarationen }
//    procedure CreateParams(var Params: TCreateParams);override;
  end;
  {ProtoType of Exe_CallBackFunction}
  tf_FormFreeCallBack=procedure ;stdcall;var
  dll_Frm: Tdll_Frm;
  FormFreeCallBack:Tf_FormFreeCallBack;
implementationuses mdidll,umainformsVar;{$R *.DFM}procedure Tdll_Frm.FormDestroy(Sender: TObject);
begin
  {notify exe-File that Form is onloaded}
  FormFreeCallBack;
end;procedure Tdll_Frm.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  action:=caFree;
end;end.

Answer 5

主程序：
program maindb;uses
  Forms,
  uexe in 'uexe.pas' {Form1},
  Umain in 'Umain.pas' {main};{$R *.RES}begin
  Application.Initialize;
  Application.CreateForm(Tmain, main);
  Application.CreateForm(TForm1, Form1);
  Application.Run;
end.mainform：
unit Umain;interfaceuses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  Menus;type
  Tmain = class(TForm)
    MainMenu1: TMainMenu;
    Datei1: TMenuItem;
    Neu1: TMenuItem;
    ffnen1: TMenuItem;
    Speichern1: TMenuItem;
    Speichernunter1: TMenuItem;
    N1: TMenuItem;
    Drucken1: TMenuItem;
    Druckereinrichtung1: TMenuItem;
    N2: TMenuItem;
    Beenden1: TMenuItem;
    Bearbeiten1: TMenuItem;
    Rckgngig1: TMenuItem;
    WiederholenBefehl1: TMenuItem;
    N3: TMenuItem;
    Ausschneiden1: TMenuItem;
    Kopieren1: TMenuItem;
    Einfgen1: TMenuItem;
    Inhalteeinfgen1: TMenuItem;
    N4: TMenuItem;
    Suchen1: TMenuItem;
    Ersetzen1: TMenuItem;
    Gehezu1: TMenuItem;
    N5: TMenuItem;
    Verknpfungen1: TMenuItem;
    Objekt1: TMenuItem;
    Fenster1: TMenuItem;
    NeuesFenster1: TMenuItem;
    Nebeneinander1: TMenuItem;
    berlappend1: TMenuItem;
    Alleanordnen1: TMenuItem;
    N6: TMenuItem;
    Verbergen1: TMenuItem;
    Zeigen1: TMenuItem;
    Hilfe1: TMenuItem;
    Inhalt1: TMenuItem;
    Index1: TMenuItem;
    Befehle1: TMenuItem;
    Verfahren1: TMenuItem;
    Tastatur1: TMenuItem;
    Suchen2: TMenuItem;
    Lernprogramm1: TMenuItem;
    Hilfebenutzen1: TMenuItem;
    Info1: TMenuItem;
  private
    { Private-Deklarationen }
  public
    { Public-Deklarationen }
  end;var
  main: Tmain;implementation{$R *.DFM}end.unit uexe;interfaceuses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  ExtCtrls, StdCtrls;type
  TForm1 = class(TForm)
    Panel1: TPanel;
    Button1: TButton;
    Memo1: TMemo;
    procedure Button1Click(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    { Private-Deklarationen }
  public
    { Public-Deklarationen }
    procedure LoadDll;
  end;
  {types for dynamical load from dll}
  TF_ShowChild = function (App:TApplication;PFormFreeCallBack:Pointer):TForm;stdcall;
  {Set old Applicaton Var in Dll to protect for GPF}
  TF_SetOldApplication=procedure ;stdcall;
  EDLLLoadError = class(Exception);
  procedure FormFreeCallBack;stdcall;
var
  Form1: TForm1;
  ChildForm:TForm;
  ShowChild :TF_ShowChild;
  SetOldApplication:TF_SetOldApplication;
  dlldbhWnd:hwnd=0;
implementationuses Umain;{$R *.DFM}
{must be called in dll to recognize if childform is onloaded}
procedure FormFreeCallBack;
begin
  ChildForm:=Nil;
end;
{dynamically load functions from dlldb.dll}
procedure TForm1.LoadDll;
var LastError:DWord;
begin
  if dlldbhWnd= 0 then begin
    dlldbhWnd:=loadLibrary('DLLDB.DLL');
    if dlldbhWnd =0 then begin
      LastError := GetLastError;
      Raise EDLLLoadError.create(IntToStr(LastError) +
                                 ': Unable to load DLLDB.dll');
    end;
    ShowChild:=getProcAddress(dlldbhWnd,'ShowChild');
    if @showChild=Nil then begin
      Raise EDLLLoadError.create(IntToStr(LastError) +
                                 ': Unable to find function ShowChild');
    end;
    SetOldApplication:=getProcAddress(dlldbhWnd,'SetOldApplication');
    if @SetOldApplication=Nil then begin
      Raise EDLLLoadError.create(IntToStr(LastError) +
                                 ': Unable to find function SetOldApplication');
    end;
  end;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
  loadDll;
  if not assigned(ChildForm) then begin
    ChildForm:=ShowChild(Application,@FormFreeCallBack);
  end;
  ChildForm.Show;
end;procedure TForm1.FormDestroy(Sender: TObject);
begin
  if dlldbhWnd<>0 then begin
    SetOldApplication;
    FreeLibrary (dlldbhWnd);
  end;
end;
end.