问一个关于DLL的问题

[Javpp]

我想在WINMAIN函数里直接动态连接DLL，DLL里打包了所有的窗体，但运行退出时出现了读内存错误，请大家帮帮忙！
代码如下：
EXE文件代码，我是将自动生成的工程去掉那个窗体，然后修改WINMAIN函数：

//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

//extern "C" __declspec (dllimport) HANDLE __stdcall LoadMainForm (TApplication *App);
HANDLE (__stdcall *LoadMainForm) (TApplication *App);
//---------------------------------------------------------------------------
WINAPI WinMain(HINSTANCE, HINSTANCE, LPSTR, int)
{
try
{
Application->Initialize ();
//Load dll
HINSTANCE HInst = LoadLibrary ("DTForm.dll");
if (HInst)
{
LoadMainForm = (HANDLE (__stdcall *) (TApplication *App)) GetProcAddress (HInst, "LoadMainForm");
if (LoadMainForm)
{
//Application->Handle = LoadMainForm (Application);
LoadMainForm (Application);
}
else
{
ShowMessage ("File Error!");
return 1;
}
}
else
{
ShowMessage ("Load dll Error!");
return 1;
}

Application->Run ();
FreeLibrary ("DTForm.dll");
}
catch (Exception &exception)
{
Application->ShowException(&exception);
}
catch (...)
{
try
{
throw Exception("");
}
catch (Exception &exception)
{
Application->ShowException(&exception);
}
}
return 0;
}
//---------------------------------------------------------------------------

DLL文件代码，只添加了一个窗口：
DLL文件：
//---------------------------------------------------------------------------

#include <vcl.h>
#include <windows.h>
#include <objbase.h>

#include "MainFrm.h"

#pragma hdrstop
//---------------------------------------------------------------------------
// Important note about DLL memory management when your DLL uses the
// static version of the RunTime Library:
//
// If your DLL exports any functions that pass String objects (or structs/
// classes containing nested Strings) as parameter or function results,
// you will need to add the library MEMMGR.LIB to both the DLL project and
// any other projects that use the DLL. You will also need to use MEMMGR.LIB
// if any other projects which use the DLL will be performing new or delete
// operations on any non-TObject-derived classes which are exported from the
// DLL. Adding MEMMGR.LIB to your project will change the DLL and its calling
// EXE's to use the BORLNDMM.DLL as their memory manager. In these cases,
// the file BORLNDMM.DLL should be deployed along with your DLL.
//
// To avoid using BORLNDMM.DLL, pass string information using "char *" or
// ShortString parameters.
//
// If your DLL uses the dynamic version of the RTL, you do not need to
// explicitly add MEMMGR.LIB as this will be done implicitly for you
//---------------------------------------------------------------------------

//载入主窗体
extern "C" __declspec(dllexport) __stdcall HANDLE LoadMainForm (TApplication *App);

TApplication *dllApp;
void DllUnload (int reason);

#pragma argsused
int WINAPI DllEntryPoint(HINSTANCE hinst, unsigned long reason, void* lpReserved)
{
//将EXE的句柄给DLL
dllApp = Application;
//Application = dllApp;
DllProc = &DllUnload;
return 1;
}
//---------------------------------------------------------------------------

HANDLE __stdcall LoadMainForm (TApplication *App)
{
Application = App;
Application->Title = "Gree AC Remote Control";
Application->Initialize ();
CoInitialize (NULL);
Application->CreateForm (__classid (TfrmMain), &frmMain);
Application->Run ();
return frmMain->Handle;
}
//---------------------------------------------------------------------------

void DllUnload (int reason)
{
if (reason == DLL_PROCESS_DETACH)
{
CoUninitialize ();

//将句柄交还给Application
Application = dllApp;
}
}
//---------------------------------------------------------------------------

DLL中窗口的代码：
CPP文件：
//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include "MainFrm.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TfrmMain *frmMain;
//---------------------------------------------------------------------------
__fastcall TfrmMain::TfrmMain(TComponent* Owner)
: TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TfrmMain::Exit1Click(TObject *Sender)
{
//这里不能使用Application->Terminate ();
//因为还没有将DLL的句柄交还给EXE，会出错
//不知道这样做对不对
Close ();
//Application->Terminate ();
}
//---------------------------------------------------------------------------

void __fastcall TfrmMain::FormDestroy(TObject *Sender)
{
DllProc (DLL_PROCESS_DETACH);
}
//---------------------------------------------------------------------------

头文件代码：
//---------------------------------------------------------------------------

#ifndef MainFrmH
#define MainFrmH
//---------------------------------------------------------------------------
#include <Classes.hpp>
#include <Controls.hpp>
#include <StdCtrls.hpp>
#include <Forms.hpp>
#include <ComCtrls.hpp>
#include <Menus.hpp>
#include <ToolWin.hpp>
//---------------------------------------------------------------------------
class TfrmMain : public TForm
{
__published: // IDE-managed Components
TCoolBar *CoolBar1;
TToolBar *ToolBar1;
TToolBar *ToolBar2;
TToolButton *ToolButton1;
TToolButton *ToolButton2;
TToolButton *ToolButton3;
TMainMenu *MainMenu1;
TMenuItem *System1;
TMenuItem *Logout1;
TMenuItem *AddUser1;
TMenuItem *ConfigUser1;
TMenuItem *DeleteUser1;
TMenuItem *Setting1;
TMenuItem *N1;
TMenuItem *Logout2;
TMenuItem *Exit1;
TMenuItem *Edit1;
TMenuItem *Add1;
TMenuItem *Inner1;
TMenuItem *OutDoor1;
TMenuItem *Help1;
TMenuItem *Help2;
TMenuItem *About1;
TMenuItem *AboutGree1;
void __fastcall Exit1Click(TObject *Sender);
void __fastcall FormDestroy(TObject *Sender);
private: // User declarations
public: // User declarations
__fastcall TfrmMain(TComponent* Owner);
};
//---------------------------------------------------------------------------
extern PACKAGE TfrmMain *frmMain;
//---------------------------------------------------------------------------
#endif

请大家指点一下，代码中可能还有别的错误，请指点，谢谢！！！

[jishiping]

DllEntryPoint 中不区分reason，每次都执行 dllApp = Application; 不知道会不会造成错误。

[Javpp]

up,还是没解决，不知道问题在哪里

[Javpp]

cczlp(不惑) ( )
好像和创建窗体的方法没关系吧
Application->Initialize ();
和
Application->Run ();
这两个函数EXE和DLL重复了，应该只要一个就可以了。
＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝

今天我在公司运行，什么错误都没有了，晕了

还有，谁有比较深入一些的CB些DLL的资料啊，找到的都是查不多的
＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝

jishiping(JSP 季世平) 老大，不知道你有没有调试，我每次退出时就出现读内存错误，调试窗口上显示内存地址的内容都是问号，但好像程序还要读那里的内容，可能就是你说的DLLENTRYPOINT中没有区分REASON的原因吧，我回去试一下。

还有，老大，我是想这样的，将所有的窗体按照功能块放到DLL中，一些公用的函数放到另外一个DLL中，然后调用，不知道这样做合理不合理。

[tiegerium2]

这样搞是为了实验吗？真的想不通，要变换一个主窗口就要变换不同版本的DLL吗？
DLL中已经有了：
Application->Initialize ();
Application->Run ();

所以上面两句（WinMain）不要了．

是不是Application->Run ()在程序结束后才返回呢？
是不是应该把FreeLibrary ("DTForm.dll")放到别的地方呢？

[Javpp]

UP，今天设置断点跟踪了Application一下，发现Application的值在EXE和DLL中不同，期待高手给解释一下，正在看INSIDE VCL，但是看不明白

[jishiping]

发现Application的值在EXE和DLL中不同
----------------------------------------------------------
如果DLL使用静态连接，那么EXE和DLL中的Application就一样了。

[Javpp]

老大，那这个和出现错误有关系吗？

你有没有运行一下看看？

[mdf2008]

>>>搞得好复杂，还没有见过BCB中这么写程序的,

我也不明白

[LLTing]

好像你想保护整个程序包括界面似的，设计思路有点儿问题吧？！
具体不说了，我以前设计带界面的DLL也出现过类似的问题，你看
看"BCB5开发人员指南"就知道了，DLL是不能这样加载的！

[jishiping]

经过实践，将 HANDLE __stdcall LoadMainForm (TApplication *App) 里面的 Application = App; 拿掉就可以了。

[Javpp]

那在WINMAIN函数里使用下面哪个函数：
Application->Handle = LoadMainForm (Application);

LoadMainForm (Application);

后来我又把DLL的代码改了一下，明天帖过来，主要是更改了DLLENTRYPOINT函数里的

[leonatcs]

Application = App;恐怕不能这样赋值！
为什么一定要把exe的application赋给dll的application呢？！

dllApplication->Handle = ExeApplication->MainForm->Handle;这样倒是可以。
既然不要主窗体，或者你可以新建一个console exe来加载你的dll。

[Javpp]

LLTing(会飞的木鱼)：
extern "C" __declspec (dllimport) HANDLE __stdcall LoadMainForm 放到DllMain.h中？
Dll.cpp才是Dll的入口啊，DllMain.h和DllMain.cpp是Dll中一个窗体的文件，怎么要把Dll的接口放到这个文件里 ？不懂。

[LLTing]

补充：你的那个DLL写的好像有问题--Dll.cpp,DllMain.h,DllMain.cpp(界面文件代码)
把extern "C" __declspec (dllimport) HANDLE __stdcall LoadMainForm
这句丢到DllMain.h中，Dll.cpp文件空着（切记），在DllMain.cpp中包含DllMain.h,
然后写处理函数就可以了。
"BCB5开发人员指南"说：当创建了一个VCL的DLL，所需VCL组件被连接到DLL，这将
导致一定量的越界(overhead)，通过将几个组件结合进一个只需要一个VCL组件支持
的DLL中可以压缩这种越界。这种规范严格限制了在DLL中使用VCL组件的范围。开发
时一定要注意！

[cygwolf]

主窗体应该非模态，用new创建，自动销毁，你用FreeLibrary ("DTForm.dll");销毁
是不对的,应该去掉。

[cczlp]

使用new而不是Application->CreateForm.
看看《避免C++Builder中的常见错误：来自TeamB的建议》就知道了。
pdf文档，文字复制不下来，楼主可在网上下载看看，很有帮助的。

[Javpp]

偶重新写了下代码，如下，现在没问题了，起码表面上没有再出错，请各位指点：
EXE的WINMAIN函数
//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

//extern "C" __declspec (dllimport) HANDLE __stdcall LoadMainForm (TApplication *App);
HANDLE (__stdcall *LoadMainForm) (TApplication *App);
//---------------------------------------------------------------------------
WINAPI WinMain(HINSTANCE, HINSTANCE, LPSTR, int)
{
try
{
//Load dll
HINSTANCE HInst = LoadLibrary ("DTForm.dll");
if (HInst)
{
LoadMainForm = (HANDLE (__stdcall *) (TApplication *App)) GetProcAddress (HInst, "LoadMainForm");
if (LoadMainForm)
{
Application->Handle = LoadMainForm (Application);
}
else
{
ShowMessage ("File Error!");
return 1;
}
}
else
{
ShowMessage ("Load dll Error!");
return 1;
}

FreeLibrary ("DTForm.dll");
}
catch (Exception &exception)
{
Application->ShowException(&exception);
}
catch (...)
{
try
{
throw Exception("");
}
catch (Exception &exception)
{
Application->ShowException(&exception);
}
}
return 0;
}
//---------------------------------------------------------------------------

[Javpp]

DLL的入口文件：
//---------------------------------------------------------------------------

#include <vcl.h>
#include <windows.h>
#include <objbase.h>

#include "MainFrm.h"

#pragma hdrstop
//---------------------------------------------------------------------------
// Important note about DLL memory management when your DLL uses the
// static version of the RunTime Library:
//
// If your DLL exports any functions that pass String objects (or structs/
// classes containing nested Strings) as parameter or function results,
// you will need to add the library MEMMGR.LIB to both the DLL project and
// any other projects that use the DLL. You will also need to use MEMMGR.LIB
// if any other projects which use the DLL will be performing new or delete
// operations on any non-TObject-derived classes which are exported from the
// DLL. Adding MEMMGR.LIB to your project will change the DLL and its calling
// EXE's to use the BORLNDMM.DLL as their memory manager. In these cases,
// the file BORLNDMM.DLL should be deployed along with your DLL.
//
// To avoid using BORLNDMM.DLL, pass string information using "char *" or
// ShortString parameters.
//
// If your DLL uses the dynamic version of the RTL, you do not need to
// explicitly add MEMMGR.LIB as this will be done implicitly for you
//---------------------------------------------------------------------------

//载入主窗体
extern "C" __declspec(dllexport) __stdcall HANDLE LoadMainForm (TApplication *App);

TApplication *dllApp;

#pragma argsused
int WINAPI DllEntryPoint(HINSTANCE hinst, unsigned long reason, void* lpReserved)
{
//根据DLL被调用还是被释放交换句柄
switch (reason)
{
case DLL_PROCESS_ATTACH: //调用DLL
{
CoInitialize (NULL);
dllApp = Application;
break;
}
case DLL_PROCESS_DETACH: //释放DLL
{
CoUninitialize ();
Application = dllApp;
break;
}
}

return 1;
}
//---------------------------------------------------------------------------

HANDLE __stdcall LoadMainForm (TApplication *App)
{
Application = App;
Application->Title = "Gree AC Remote Control";
Application->Initialize ();
Application->CreateForm (__classid (TfrmMain), &frmMain);
Application->Run ();
return frmMain->Handle;
}
//---------------------------------------------------------------------------

[Javpp]

主窗体代码：
HPP文件：
//---------------------------------------------------------------------------

#ifndef MainFrmH
#define MainFrmH
//---------------------------------------------------------------------------
#include <Classes.hpp>
#include <Controls.hpp>
#include <StdCtrls.hpp>
#include <Forms.hpp>
#include <ComCtrls.hpp>
#include <Menus.hpp>
#include <ToolWin.hpp>
//---------------------------------------------------------------------------
class TfrmMain : public TForm
{
__published: // IDE-managed Components
TCoolBar *CoolBar1;
TToolBar *ToolBar1;
TToolBar *ToolBar2;
TToolButton *ToolButton1;
TToolButton *ToolButton2;
TToolButton *ToolButton3;
TMainMenu *MainMenu1;
TMenuItem *System1;
TMenuItem *Logout1;
TMenuItem *AddUser1;
TMenuItem *ConfigUser1;
TMenuItem *DeleteUser1;
TMenuItem *Setting1;
TMenuItem *N1;
TMenuItem *Logout2;
TMenuItem *Exit1;
TMenuItem *Edit1;
TMenuItem *Add1;
TMenuItem *Inner1;
TMenuItem *OutDoor1;
TMenuItem *Help1;
TMenuItem *Help2;
TMenuItem *About1;
void __fastcall ToolButton1Click(TObject *Sender);
void __fastcall About1Click(TObject *Sender);
void __fastcall Exit1Click(TObject *Sender);
private: // User declarations
public: // User declarations
__fastcall TfrmMain(TComponent* Owner);
};
//---------------------------------------------------------------------------
extern PACKAGE TfrmMain *frmMain;
//---------------------------------------------------------------------------
#endif


CPP文件：
//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include "MainFrm.h"
#include "AboutFrm.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TfrmMain *frmMain;
//---------------------------------------------------------------------------
__fastcall TfrmMain::TfrmMain(TComponent* Owner)
: TForm(Owner)
{
this->Position = poDesktopCenter;
}
//---------------------------------------------------------------------------

void __fastcall TfrmMain::ToolButton1Click(TObject *Sender)
{
ShowMessage ("asdf");
}
//---------------------------------------------------------------------------

void __fastcall TfrmMain::About1Click(TObject *Sender)
{
TfrmAbout *frmAbout = new TfrmAbout (Application);
frmAbout->ShowModal ();
delete frmAbout;
frmAbout = NULL;
}
//---------------------------------------------------------------------------

void __fastcall TfrmMain::Exit1Click(TObject *Sender)
{
Close ();
}
//---------------------------------------------------------------------------

[sczyq]

Dll 窗口退出时，应当发放一条消息，通知主程序释放DLL，才是正解