D2009 UP3和D2010 V3449 都没解决DLL的问题！（值得大家研究）

DLL的DPR代码如下：
library DllPro;

{ Important note about DLL memory management: ShareMem must be the
  first unit in your library's USES clause AND your project's (select
  Project-View Source) USES clause if your DLL exports any procedures or
  functions that pass strings as parameters or function results. This
  applies to all strings passed to and from your DLL--even those that
  are nested in records and classes. ShareMem is the interface unit to
  the BORLNDMM.DLL shared memory manager, which must be deployed along
  with your DLL. To avoid using BORLNDMM.DLL, pass string information
  using PChar or ShortString parameters. }

uses
  SimpleShareMem,
  SysUtils,
  Forms,
  Windows,
  Classes,
  uIntf in 'uIntf.pas',
  uImp in 'uImp.pas',
  Unit2 in 'Unit2.pas' {Form2};

{$R *.res}

var
  DLLApp: TApplication;

function InitDLL(App: TApplication): Intf_DLLTest;
begin
  //问题出在这句上,
  //如果没有这句程序退出时就不会出错。
  //但是这句在DLL里一般都是要这样做的。否则DLL里的窗口显示的图标都是不正确的。
  //这样的代码在Delphi 2007以前是不会有问题的。
  Application := App;

  Obj_DLLTest := TImpl_DLLTest.Create(nil);

  Intf_DLLTest1 := Obj_DLLTest as Intf_DLLTest;
  Result := Intf_DLLTest1;
end;

procedure UnInitDLL;
begin
  FreeAndNil(Obj_DLLTest);
end;

procedure ExitDLL(Reason: Integer);
begin
  if Reason = DLL_PROCESS_DETACH then
  begin
Application := DLLApp;
  end;
end;

exports
  InitDLL,
  UnInitDLL;

begin
  DLLApp := Application;
  DLLProc := @ExitDLL;

end.

调用DLL的主程序的主窗口的代码如下：

unit Main;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
Button1: TButton;
procedure Button1Click(Sender: TObject);
procedure FormDestroy(Sender: TObject);
  private
{ Private declarations }
  public
{ Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

uses
  uIntf;

var
  InitDLL: function (App: TApplication): Intf_DLLTest;
  UnInitDLL: procedure;

  DllHandle: THandle;

procedure TForm1.Button1Click(Sender: TObject);
begin
  DllHandle := LoadLibrary('DllPro.dll');
  if DllHandle > 0 then
  begin
InitDLL := GetProcAddress(DllHandle, 'InitDLL');
if Assigned(InitDLL) then
begin
   Intf_DLLTest1 := InitDLL(Application);

   if Intf_DLLTest1 <> nil then
   begin
      Intf_DLLTest1.ShowTestForm;
   end;
end;
  end;
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  if DllHandle > 0 then
  begin
if Assigned(Intf_DLLTest1) then Intf_DLLTest1 := nil;

UnInitDLL := GetProcAddress(DllHandle, 'UnInitDLL');
if Assigned(UnInitDLL) then
begin
   UnInitDLL;
end;

FreeLibrary(DllHandle);
  end;
end;

end.

详细原代码请看这里：