Solved

static_cast error with Visual Studio .NET but not with VC6

Posted on 2003-10-31
3
579 Views
Last Modified: 2008-02-01
I use a third party code to implement a plug-in architecture in my application (the code: http://www.codeproject.com/library/piarchitecture.asp).

The code works fine with the compiler of VC6 but when I compile with VS .NET I received a lot of errors C2440 like this one:

static_cast' : cannot convert from 'int (__thiscall CViewInPlugIn::* )(LPCREATESTRUCT)' to 'int (__thiscall CWnd::* )(LPCREATESTRUCT)'
 
CViewInPlugIn is derived from CPlugInMap and CPlugInMap is derived from CCmdTarget. Maybe the new compiler can't cast a CCmdTarget class to a CWnd class? I know that VS.NET Compiler is more strict with Message Map but I don't know how to resolve or bypass this problem.

=============================================
Here some parts of my code:

class CViewInPlugIn : public CPlugInMap  
{
................
      // ClassWizard generated virtual function overrides
      //{{AFX_VIRTUAL(CViewInPlugIn)
      afx_msg int OnCreate(LPCREATESTRUCT lpCreateStruct);
      //}}AFX_VIRTUAL
................
};


//Here my implementation
BEGIN_MESSAGE_MAP(CViewInPlugIn, CPlugInMap)
      //{{AFX_MSG_MAP(CViewInPlugIn)
      ON_WM_CREATE()
      //}}AFX_MSG_MAP
END_MESSAGE_MAP()

int CViewInPlugIn::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
      ...............

      return TRUE ;
}

and the declaration of CPlugInMap:
class _PLUGIN_API CPlugInMap : public CCmdTarget
{
      friend class CPlugInApp ;
      DECLARE_DYNCREATE(CPlugInMap)

......................

      DECLARE_MESSAGE_MAP()
};
0
Comment
Question by:Frankbe
  • 2
3 Comments
 
LVL 48

Accepted Solution

by:
AlexFM earned 500 total points
ID: 9660628
I reproduced this error compiling the sample application from CodeProject. PlugIn1 project, MFExamplePI.cpp, lines:

BEGIN_MESSAGE_MAP(CMFPI, CPlugInMap)
    //{{AFX_MSG_MAP(CMFPI)
    ON_WM_CREATE()
    ON_COMMAND(ID_VIEW_MYNEWTOOLBAR, OnViewMyNewToolbar)
    ON_UPDATE_COMMAND_UI(ID_VIEW_MYNEWTOOLBAR, OnUpdateViewMyNewToolbar)
    ON_COMMAND(ID_FILE_SOMENEWOPTION, OnSomeNewOption)
    //}}AFX_MSG_MAP
END_MESSAGE_MAP()

The same error message in ON_WM_CREATE line. Solution - add the following lines in the beginning of cpp file:

#undef ON_WM_CREATE
#define ON_WM_CREATE() \
    { WM_CREATE, 0, 0, 0, AfxSig_is, \
        (AFX_PMSG) (AFX_PMSGW) \
        (reinterpret_cast< int (AFX_MSG_CALL CWnd::*)(LPCREATESTRUCT) > (OnCreate)) },

This is ON_WM_CREATE macro with static_cast replaced by reinterpret_cast. Not so nice, but should work.
0
 

Author Comment

by:Frankbe
ID: 9667051
When you execute the compiled program, do you receive an unhandled exception : access violation reading location 0x00000000?
0
 
LVL 48

Expert Comment

by:AlexFM
ID: 9669246
Actually, I didn't execute it at all. Possibly it contains some bugs, I don't know. If this happens also in VC++ 6, this is not result of ON_WM_CREATE compilation problem.
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

In my previous article (http://www.experts-exchange.com/Programming/Languages/.NET/.NET_Framework_3.x/A_4362-Serialization-in-NET-1.html) we saw the basics of serialization and how types/objects can be serialized to Binary format. In this blog we wi…
This article shows how to deploy dynamic backgrounds to computers depending on the aspect ratio of display
This is a video describing the growing solar energy use in Utah. This is a topic that greatly interests me and so I decided to produce a video about it.
Need to grow your business through quality cloud solutions? With everything required to build a cloud platform and solution, you may feel like the distance between you and the cloud is quite long. Help is here. Spend some time learning about the Con…

932 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

12 Experts available now in Live!

Get 1:1 Help Now