C / C++ / MFC

1. OR the Flags member of the OPENFILENAME structure with OFN_ENABLEHOOK. You might also want to OR it with OFN_NODEREFERENCELINKS while you're at it to keep users from making a shortcut to a location outside your limited scope.
   
2. Set the lpfnHook to a HOOKPROC callback.
   

CComboBox *pCB = (CComboBox *)GetDlgItem(IDC_CODEGENTBL_DB);
pCB->ResetContent();

DBConnection *pDBConn = &(((CodeGenOpts *)GetParent())->m_oDBConn);
DBStatement oStmt(pDBConn);
oStmt.AllocStatement();

int iDBCount = 0;
CString cDBName;
SQLRETURN iResult = SQLTables(oStmt.GetStmtHdl(),
                               (unsigned char *)"%", 1,
                               (unsigned char *)"",0,
                               (unsigned char *)"",0,
                               (unsigned char *)"",0);
if (iResult == SQL_SUCCESS || iResult == SQL_SUCCESS_WITH_INFO)
  {
    while (oStmt.FetchNext())
      {
        cDBName = oStmt.GetString(1);
        if (!cDBName.IsEmpty())
          {
            pCB->AddString(cDBName);
            iDBCount++;
          }
      }

    oStmt.EndSQL();
  }

//header file
class ExportedClass
{
public:
    ExportedClass();
    ~ExportedClass
    void Abc();
};

ExportedClass* GetExportedClass()
{
    return new ExportedClass();
}

GETEXPORTEDCLASS func = GetProcAddress(...,"GetExportedClass");
ExportedClass* pec = (func)();
pec->Abc();