VC下使用ADO数据库访问技术时遇到的问题

昨天在编写一个ADO Demo时遇到了一些问题，就简单整理了一下。
1. 在编译了几次之后突然出现了以下错误，搞了好半天才终于发现，原来是文件视图中多了一个DLGCORE.CPP源文件，于是乎就将其删除，重新编译，果然通过。

Compiling resources...Compiling...DLGCORE.CPPD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(45) : warning C4273: 'protected: static struct AFX_MSGMAP const CDialog::messageMap' : inconsistent dll linkage.  dllexport assumed.D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(45) : error C2491: 'CDialog::messageMap' : definition of dllimport static data member not allowedD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(52) : error C2065: 'WM_COMMANDHELP' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(53) : error C2065: 'WM_HELPHITTEST' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(58) : error C2065: 'WM_QUERY3DCONTROLS' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(81) : error C2065: '_AfxCompareClassName' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(101) : error C2065: 'IS_COMMAND_ID' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(171) : error C2065: '_AfxCheckDialogTemplate' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(277) : error C2065: 'AfxDeferRegisterClass' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(277) : error C2065: 'AFX_WNDCOMMCTLS_REG' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(278) : error C2065: 'AFX_WNDCOMMCTLSNEW_REG' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(298) : error C2653: 'CDialogTemplate' : is not a class or namespace nameD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(299) : error C2660: 'GetFont' : function does not take 3 parametersD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(312) : error C2065: 'CDialogTemplate' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(312) : error C2146: syntax error : missing ';' before identifier 'dlgTemp'D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(312) : error C2065: 'dlgTemp' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(313) : error C2228: left of '.SetSystemFont' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(314) : error C2228: left of '.Detach' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(325) : error C2065: 'AfxHookWindowCreate' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(334) : error C2065: 'DELETE_EXCEPTION' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(348) : error C2065: 'AfxUnhookWindowCreate' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(647) : error C2079: 'info' uses undefined struct 'AFX_CMDHANDLERINFO'D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(651) : error C2664: 'OnCmdMsg' : cannot convert parameter 4 from 'int *' to 'struct AFX_CMDHANDLERINFO *'        Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style castD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(655) : error C2664: 'OnCmdMsg' : cannot convert parameter 4 from 'int *' to 'struct AFX_CMDHANDLERINFO *'        Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style castD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(734) : error C2065: 'DLGTEMPLATEEX' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(734) : error C2059: syntax error : ')'D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(735) : error C2143: syntax error : missing ';' before '{'D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(737) : error C2059: syntax error : ')'D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(738) : error C2059: syntax error : ')'D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(739) : error C2059: syntax error : ')'D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(741) : error C2181: illegal else without matching ifD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(778) : error C2065: 'HID_BASE_RESOURCE' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(827) : error C2373: '_AfxCheckDialogTemplate' : redefinition; different type modifiersD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(854) : error C2065: 'pTemplate' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(854) : error C2059: syntax error : ')'D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(856) : error C2227: left of '->signature' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(857) : error C2227: left of '->style' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(893) : warning C4273: 'public: static struct CRuntimeClass const CDialog::classCDialog' : inconsistent dll linkage.  dllexport assumed.D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(893) : error C2491: 'CDialog::classCDialog' : definition of dllimport static data member not allowedError executing cl.exe.SCommTest.exe - 37 error(s), 2 warning(s)

通过查找资料，了解到原来这是VC安装目录下的一个源文件，打开后我们可以看到以下注释：

// This is a part of the Microsoft Foundation Classes C++ library.// Copyright (C) 1992-1998 Microsoft Corporation// All rights reserved.//// This source code is only intended as a supplement to the// Microsoft Foundation Classes Reference and related// electronic documentation provided with the library.// See these sources for detailed information regarding the// Microsoft Foundation Classes product.

简单地说，就是MFC中的几个封装函数的实现。至于它怎么会突然出现在工程中，还有待深究。。。。。

2. 刚开始使用

pConn ->Open(_bstr_t)connString, "", "", adConnectUnspecified);pSet = pConn ->Excute("select * from studentinfo", NULL, adCmdText);

这种方式来查询，结果在后面的移动记录时出现了问题。

原因：这种方式RecordSet的参数CursorType的默认值为forward-only，使得这种方式不支持游标的双向移动，导致只有RecordSet对象的MoveFirst()和MoveNext()可用，而在使用MoveFirst()和MovePrevious()时就会弹出“runtime error”；

随后改变了记录的查询方式，从而解决了这个问题：

pConn ->Open((_bstr_t)connString, "", "", adConnectUnspecified);pSet -> Open("select * from studentinfo", (_bstr_t)(*IDispatch)pConn), adOpenDynamic, adLockOptimistic, adCmdText);

这次显式地将RecordSet对象的参数CursorType的值改为了adOpenDynamic，使得其支持游标的双向移动。
3. 由于在查找时需要扫描记录，所以要获取记录总数，但是每次获取到的都是-1，所以将光标类型设置为静态，然后重新编译，运行。
但是再次编译时又出现了以下错误，通过排查，发现文件视图中突然增加了一个CMDTARG.CPP文件，有了上次的经验，所以还是将其删除，当然也就顺利地通过了编译、链接。

Compiling...CMDTARG.CPPD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(51) : error C2027: use of undefined type 'COleDispatchImpl'        d:\program files\microsoft visual studio\vc98\mfc\include\afxwin.h(1721) : see declaration of 'COleDispatchImpl'D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(51) : error C2227: left of '->Disconnect' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(69) : error C2079: 'mmf' uses undefined union 'MessageMapFunctions'D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(70) : error C2228: left of '.pfn' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(76) : error C2027: use of undefined type 'AFX_CMDHANDLERINFO'        d:\program files\microsoft visual studio\vc98\mfc\include\afxwin.h(1303) : see declaration of 'AFX_CMDHANDLERINFO'D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(76) : error C2227: left of '->pTarget' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(77) : error C2027: use of undefined type 'AFX_CMDHANDLERINFO'        d:\program files\microsoft visual studio\vc98\mfc\include\afxwin.h(1303) : see declaration of 'AFX_CMDHANDLERINFO'D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(77) : error C2227: left of '->pmf' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(77) : error C2228: left of '.pfn' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(87) : error C2228: left of '.pfn_COMMAND' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(94) : error C2228: left of '.pfn_bCOMMAND' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(101) : error C2228: left of '.pfn_COMMAND_RANGE' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(107) : error C2228: left of '.pfn_COMMAND_EX' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(112) : error C2065: 'AFX_NOTIFY' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(112) : error C2065: 'pNotify' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(112) : error C2059: syntax error : ')'D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(114) : error C2227: left of '->pResult' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(115) : error C2227: left of '->pNMHDR' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(116) : error C2228: left of '.pfn_NOTIFY' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(116) : error C2227: left of '->pNMHDR' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(116) : error C2227: left of '->pResult' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(121) : error C2059: syntax error : ')'D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(123) : error C2227: left of '->pResult' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(124) : error C2227: left of '->pNMHDR' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(125) : error C2228: left of '.pfn_bNOTIFY' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(125) : error C2227: left of '->pNMHDR' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(125) : error C2227: left of '->pResult' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(130) : error C2059: syntax error : ')'D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(132) : error C2227: left of '->pResult' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(133) : error C2227: left of '->pNMHDR' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(134) : error C2228: left of '.pfn_NOTIFY_RANGE' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(134) : error C2227: left of '->pNMHDR' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(135) : error C2227: left of '->pResult' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(140) : error C2059: syntax error : ')'D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(142) : error C2227: left of '->pResult' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(143) : error C2227: left of '->pNMHDR' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(144) : error C2228: left of '.pfn_NOTIFY_EX' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(144) : error C2227: left of '->pNMHDR' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(145) : error C2227: left of '->pResult' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(156) : error C2228: left of '.pfn_UPDATE_COMMAND_UI' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(170) : error C2228: left of '.pfn_UPDATE_COMMAND_UI_RANGE' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(178) : error C2228: left of '.pfn_OTHER' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(181) : error C2228: left of '.pfn_OTHER_EX' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(226) : error C2027: use of undefined type 'COleCmdUI'        d:\program files\microsoft visual studio\vc98\mfc\include\afxwin.h(1461) : see declaration of 'COleCmdUI'D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(226) : error C2227: left of '->m_pguidCmdGroup' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(243) : error C2027: use of undefined type 'COleCmdUI'        d:\program files\microsoft visual studio\vc98\mfc\include\afxwin.h(1461) : see declaration of 'COleCmdUI'D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(243) : error C2227: left of '->m_nID' must point to class/struct/unionD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(279) : error C2065: 'AfxFindMessageEntry' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(279) : error C2440: '=' : cannot convert from 'int' to 'const struct AFX_MSGMAP_ENTRY *'        Conversion from integral type to pointer type requires reinterpret_cast, C-style cast or function-style castD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(364) : warning C4273: 'protected: static struct AFX_MSGMAP const CCmdTarget::messageMap' : inconsistent dll linkage.  dllexport assumed.D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(364) : error C2491: 'CCmdTarget::messageMap' : definition of dllimport static data member not allowedD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(399) : warning C4273: 'protected: static struct AFX_DISPMAP const CCmdTarget::dispatchMap' : inconsistent dll linkage.  dllexport assumed.D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(399) : error C2491: 'CCmdTarget::dispatchMap' : definition of dllimport static data member not allowedD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(439) : warning C4273: 'protected: static struct AFX_EVENTSINKMAP const CCmdTarget::eventsinkMap' : inconsistent dll linkage.  dllexport assumed.D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(439) : error C2491: 'CCmdTarget::eventsinkMap' : definition of dllimport static data member not allowedD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(488) : warning C4273: 'protected: static struct AFX_INTERFACEMAP const CCmdTarget::interfaceMap' : inconsistent dll linkage.  dllexport assumed.D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(488) : error C2491: 'CCmdTarget::interfaceMap' : definition of dllimport static data member not allowedD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(509) : error C2065: 'AfxLockGlobals' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(509) : error C2065: 'CRIT_TYPELIBCACHE' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(516) : error C2065: 'AfxUnlockGlobals' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(551) : warning C4273: 'protected: static struct AFX_CONNECTIONMAP const CCmdTarget::connectionMap' : inconsistent dll linkage.  dllexport assumed.D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(551) : error C2491: 'CCmdTarget::connectionMap' : definition of dllimport static data member not allowedD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(590) : warning C4273: 'protected: static struct AFX_OLECMDMAP const CCmdTarget::commandMap' : inconsistent dll linkage.  dllexport assumed.D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(590) : error C2491: 'CCmdTarget::commandMap' : definition of dllimport static data member not allowedD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(701) : error C2065: 'afxData' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(701) : error C2228: left of '.hbmMenuDot' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(704) : error C2228: left of '.hbmMenuDot' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(706) : error C2228: left of '.hbmMenuDot' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(732) : error C2065: 'AfxSetWindowText' : undeclared identifierD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(750) : error C2079: 'info' uses undefined struct 'AFX_CMDHANDLERINFO'D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(751) : error C2228: left of '.pTarget' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(752) : error C2664: 'OnCmdMsg' : cannot convert parameter 4 from 'int *' to 'struct AFX_CMDHANDLERINFO *'        Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style castD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(778) : error C2228: left of '.hbmMenuDot' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(809) : error C2228: left of '.hbmMenuDot' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(811) : error C2228: left of '.hbmMenuDot' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(815) : error C2228: left of '.hbmMenuDot' must have class/struct/union typeD:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(859) : warning C4273: 'public: static struct CRuntimeClass const CCmdTarget::classCCmdTarget' : inconsistent dll linkage.  dllexport assumed.D:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC\CMDTARG.CPP(859) : error C2491: 'CCmdTarget::classCCmdTarget' : definition of dllimport static data member not allowedError executing cl.exe.CMDTARG.OBJ - 71 error(s), 7 warning(s)

对于这种情况，还是和上面一样，就是工程文件中多了一个CMDTARG.CPP文件，同样这也是VC安装路径下的一个源文件。打开后会发现和上面一样的注释：

// This is a part of the Microsoft Foundation Classes C++ library.// Copyright (C) 1992-1998 Microsoft Corporation// All rights reserved.//// This source code is only intended as a supplement to the// Microsoft Foundation Classes Reference and related// electronic documentation provided with the library.// See these sources for detailed information regarding the// Microsoft Foundation Classes product.

当然，也是MFC中几个函数的实现。