派生类，重载dwginFields()等函数的问题

zhengkuo

我自己做了一个派生类weltopMyclassObj:AcDbObject, 然后用它创建对象并加入到字典中
但编译时出现如下错误：
MyClassProCommands.obj : error LNK2001: unresolved external symbol "public: virtual enum Acad::ErrorStatus  __thiscall WeltopMyClassObj::dxfOutFields(class AcDbDxfFiler *)const " (?dxfOutFields@WeltopMyClassObj@@UBE?AW4ErrorStatus@Acad@@PAVAcDbDxfFi
ler@@@Z)
MyClassProCommands.obj : error LNK2001: unresolved external symbol "public: virtual enum Acad::ErrorStatus  __thiscall WeltopMyClassObj::dxfInFields(class AcDbDxfFiler *)" (?dxfInFields@WeltopMyClassObj@@UAE?AW4ErrorStatus@Acad@@PAVAcDbDxfFiler@@@Z)
MyClassProCommands.obj : error LNK2001: unresolved external symbol "public: virtual enum Acad::ErrorStatus  __thiscall WeltopMyClassObj::dwgOutFields(class AcDbDwgFiler *)const " (?dwgOutFields@WeltopMyClassObj@@UBE?AW4ErrorStatus@Acad@@PAVAcDbDwgFi
ler@@@Z)
MyClassProCommands.obj : error LNK2001: unresolved external symbol "public: virtual enum Acad::ErrorStatus  __thiscall WeltopMyClassObj::dwgInFields(class AcDbDwgFiler *)" (?dwgInFields@WeltopMyClassObj@@UAE?AW4ErrorStatus@Acad@@PAVAcDbDwgFiler@@@Z)
MyClassProCommands.obj : error LNK2001: unresolved external symbol "public: virtual class AcRxClass * __thiscall WeltopMyClassObj::isA(void)const " (?isA@WeltopMyClassObj@@UBEPAVAcRxClass@@XZ)
MyClassProCommands.obj : error LNK2001: unresolved external symbol "public: virtual __thiscall WeltopMyClassObj::~WeltopMyClassObj(void)" (??1WeltopMyClassObj@@UAE@XZ)
MyClassProCommands.obj : error LNK2001: unresolved external symbol "public: enum Acad::ErrorStatus  __thiscall WeltopMyClassObj::mintVal(short &)" (?mintVal@WeltopMyClassObj@@QAE?AW4ErrorStatus@Acad@@AAF@Z)
Debug/WeltopMyClassPro.arx : fatal error LNK1120: 7 unresolved externals
Error executing link.exe.


请问如何解决？