Calling Win32 DLL from 64-bit WPF through ATL 32-bit Surrogate COM

(1) How to tell if a DLL is 32-bit or 64-bit

 dumpbin /headers MyServer.dll to tell by file Header x86 or x64

(2) Run 32-Bit COM in surrogate Procese so can be called from 64-bit WPF.(one kind of IPC)
       http://www.gfi.com/blog/32bit-object-64bit-environment/ 


 
   Locate your COM object GUID under the HKey_Classes_Root\Wow6432Node\CLSID\[GUID] 
  
    Once located add a new REG_SZ (string) Value. Name should be AppID and data should be the same COM object GUID you have just searched for  
  
    Add a new key under HKey_Classes_Root\Wow6432Node\AppID\
    The new key should be called the same as the com object GUID  
  
    Under the new key you just added, add a new REG_SZ (string) Value, and call it DllSurrogate. Leave the value empty  
 
    Create a new Key under HKey_Local_Machine\Software\Classes\AppID\
    Again the new key should be called the same as the COM object’s GUID. No values are necessary to be added under this key. 

(3) Step-by-step ALT 32-bit COM Creation (check to make sure project properties are x86)
      http://msdn.microsoft.com/en-us/library/dssw0ch4%28d=printer,v=vs.90%29.aspx
      http://msdn.microsoft.com/en-us/library/9yb4317s.aspx
    Note that C# COM is not usable in (2), especially HKey_Classes_Root\Wow6432Node\CLSID\[GUID] is not there. 
    Also each build of ATL COM project will override this location and need to add back AppID={Guid}
(4) A good overall review of 64-bit calling 32-bit using IPC
    http://blog.mattmags.com/2007/06/30/accessing-32-bit-dlls-from-64-bit-code/

(5) Dynamic Loading Win32 DLL to access its functions:

#pragma hdrstop
#pragma package(smart_init)

// CObject1

HINSTANCE hMWXUSB=0;
typedef int (__cdecl *MYPROC)(LPWSTR); 

typedef unsigned char (ACCEPT_LED)(int data);
ACCEPT_LED *lpacceptled;

typedef unsigned char (OPEN_USB)(void);
OPEN_USB *lpopenusb;


STDMETHODIMP CObject1::get_GetANum(SHORT* pVal)
{
 hMWXUSB=LoadLibrary(L"MWXUSB.DLL");
 MYPROC Accept_LED; 

 //Accept_LED = (MYPROC) GetProcAddress(hMWXUSB, "Accept_LED"); 

    if( (hMWXUSB = LoadLibrary(L"MWXUSB.DLL")) == NULL )
   {
        *pVal=-5;
        return S_OK;
   }

       if( (lpopenusb=(OPEN_USB*)GetProcAddress(hMWXUSB,"Open_USB" ))==NULL )
   {
        *pVal=-6;
        return S_OK;
   }
       unsigned char ucOpen;
   ucOpen =  (*lpopenusb)();

    if( (lpacceptled=(ACCEPT_LED*)GetProcAddress(hMWXUSB,"Accept_LED" ))==NULL )
   {
       *pVal=-1105;
        return S_OK;
   }
    unsigned char ch;
 ch = (*lpacceptled)(1);
  if(ch)
   {
    *pVal=-2105;
    return S_OK;
  }


 *pVal=105;

 return S_OK;
}

Call 3rd party DLL from ATL COM

(1) use tool to generate def and .lib from DLL ( assuming no header file)
    http://purefractalsolutions.com/show.php?a=utils/expdef

(2) VC++ project linker-->input additional dependency

(3) declare and use in CPP

extern "C"   unsigned char Open_USB();
extern "C"   unsigned char Accept_LED(int value);
extern "C"  void Set_Callback(void* pAny);

void(__stdcall*p)(int);  // calling convention matching far pascal, for most c function

//void __cdecl* p;  // ptrAny


static void __stdcall CB1(int value)  {..} instance function would hast this->* so callback must use static to remove this.

 p = &CB1;
 ::Open_USB();
 ::Accept_LED(0);
 ::Set_Callback(p);

again cannot use __cdecl must use __stdcall. It turns out Calling Conversion even affect [DllImport] when re-target .net 4.0 from .net 4.0, must specify CDecl in DllImports

Manually add Connection Point support after ATL Simple object wizard already run

After running ATL COM Simple object wizard without check "Connection Points", manual steps are need to add this support.

(1) myserver.h---IConnectionPointContainer/Impl, COM_MAP, IEvents

#include "ATLProject1_i.h"
#include "_IMyServerEvents_CP.h"


class ATL_NO_VTABLE CMyServer :
 public CComObjectRootEx<CComSingleThreadModel>,
 public CComCoClass<CMyServer, &CLSID_MyServer>,
 public IConnectionPointContainerImpl<CMyServer>,
 public CProxy_IMyServerEvents<CMyServer>,
 public IDispatchImpl<IMyServer, &IID_IMyServer, &LIBID_ATLProject1Lib, /*wMajor =*/ 1, /*wMinor =*/ 0>
{


BEGIN_COM_MAP(CMyServer)
 COM_INTERFACE_ENTRY(IMyServer)
 COM_INTERFACE_ENTRY(IDispatch)
 COM_INTERFACE_ENTRY(IConnectionPointContainer)
END_COM_MAP()

BEGIN_CONNECTION_POINT_MAP(CMyServer)
 CONNECTION_POINT_ENTRY(__uuidof(_IMyServerEvents))
END_CONNECTION_POINT_MAP()

(2)   .\atlproject1\atlproject1\atlproject1.vcxproj.filters -- need one include

    <ClInclude Include="ATLProject1_i.h">
      <Filter>Generated Files</Filter>
    </ClInclude>
    <ClInclude Include="_IMyServerEvents_CP.h">
      <Filter>Header Files</Filter>
    </ClInclude>
    <ClInclude Include="MyServer.h">
      <Filter>Header Files</Filter>
    </ClInclude>
  </ItemGroup>


(3).\atlproject1\atlproject1\atlproject1.vcxproj --- include .h for compiler
 

  <ItemGroup>
    <ClInclude Include="ATLProject1_i.h" />
    <ClInclude Include="dllmain.h" />
    <ClInclude Include="MyServer.h" />
    <ClInclude Include="Resource.h" />
    <ClInclude Include="stdafx.h" />
    <ClInclude Include="targetver.h" />
    <ClInclude Include="xdlldata.h" />
    <ClInclude Include="_IMyServerEvents_CP.h" />
  </ItemGroup>



(4)   .\atlproject1\atlproject1\atlproject1.idl  -- disinterface and coclass

library ATLProject1Lib
{
 importlib("stdole2.tlb");
 [
  uuid(1D071C81-6C67-458F-9B35-992DBAE162D8) // one of these are duplicate 
  uuid(118E250A-B298-4749-90D8-36C764237BA4)  
 ]
 dispinterface _IMyServerEvents
 {
  properties:
  methods:
 };
 [
  uuid(48A5B08F-ED8F-4F1F-8344-5F7C913FB895)  
 ]
 coclass MyServer
 {
  [default] interface IMyServer;
  [default, source] dispinterface _IMyServerEvents;
 };
};


Notes:
(n1) to user Connection point, Add Method to _IMyServerEvents (Class View Context Menu) e.g. signature CB(int data). 
Then Add->Connection point onto CMyServer Class (again Class View Ctx Menu) select _IMyS erverEvents in
 Source Interface List. Now there will be a function Fire_CB to fire COM Event into WPF client

(n2) MyServer.rgs need update ForceRemove {dispinterface _IMyServerEvents GUI in IDL} = s 'MyServer Class'

(n3) Content of  [project dir]\_IMyServerEvents_CP.h
#pragma once

using namespace ATL;

template 
class CProxy_IMyServerEvents : public IConnectionPointImpl
{
 // WARNING: This class may be regenerated by the wizard
public:
};