error LNK2019: unresolved external symbol

error LNK2019: unresolved external symbol

1>TabConParView.obj : error LNK2019: unresolved external symbol "public: __thiscall CDCommonParamCtl::CDCommonParamCtl(void)" (??0CDCommonParamCtl@@QAE@XZ) referenced in function "protected: __thiscall CTabConParView::CTabConParView(void)" (??0CTabConParView@@IAE@XZ)
1>TabConParView.obj : error LNK2019: unresolved external symbol "public: __thiscall CDCommonParamCtl::~CDCommonParamCtl(void)" (??1CDCommonParamCtl@@QAE@XZ) referenced in function "protected: virtual __thiscall CTabConParView::~CTabConParView(void)" (??1CTabConParView@@MAE@XZ)
1>TabConParView.obj : error LNK2019: unresolved external symbol "public: void __thiscall CDCommonParamCtl::ShowWindow(unsigned long,int)" (?ShowWindow@CDCommonParamCtl@@QAEXKH@Z) referenced in function "public: void __thiscall CTabConParView::CreateParamWnd(unsigned long,unsigned long,int)" (?CreateParamWnd@CTabConParView@@QAEXKKH@Z)
1>TabConParView.obj : error LNK2019: unresolved external symbol "public: void __thiscall CDCommonParamCtl::WindowMove(unsigned long,class CRect)" (?WindowMove@CDCommonParamCtl@@QAEXKVCRect@@@Z) referenced in function "public: void __thiscall CTabConParView::CreateParamWnd(unsigned long,unsigned long,int)" (?CreateParamWnd@CTabConParView@@QAEXKKH@Z)
1>TabConParView.obj : error LNK2019: unresolved external symbol "public: void __thiscall CDCommonParamCtl::ChangeParamConfig(unsigned long,short)" (?ChangeParamConfig@CDCommonParamCtl@@QAEXKF@Z) referenced in function "public: void __thiscall CTabConParView::CreateParamWnd(unsigned long,unsigned long,int)" (?CreateParamWnd@CTabConParView@@QAEXKKH@Z)
1>TabConParView.obj : error LNK2019: unresolved external symbol "public: unsigned long __thiscall CDCommonParamCtl::CreateParamConfig(unsigned long,class ATL::CStringT<char,class StrTraitMFC_DLL<char,class ATL::ChTraitsCRT<char> > >)" (?CreateParamConfig@CDCommonParamCtl@@QAEKKV?$CStringT@DV?$StrTraitMFC_DLL@DV?$ChTraitsCRT@D@ATL@@@@@ATL@@@Z) referenced in function "public: void __thiscall CTabConParView::CreateParamWnd(unsigned long,unsigned long,int)" (?CreateParamWnd@CTabConParView@@QAEXKKH@Z)
1>TabConParView.obj : error LNK2019: unresolved external symbol "public: void __thiscall CDCommonParamCtl::SetStatDevID(unsigned long,unsigned long,unsigned long)" (?SetStatDevID@CDCommonParamCtl@@QAEXKKK@Z) referenced in function "public: void __thiscall CTabConParView::CreateParamWnd(unsigned long,unsigned long,int)" (?CreateParamWnd@CTabConParView@@QAEXKKH@Z)
1>TabConParView.obj : error LNK2019: unresolved external symbol "public: class ATL::CStringT<char,class StrTraitMFC_DLL<char,class ATL::ChTraitsCRT<char> > > __thiscall CDCommonParamCtl::ChangeMeasureType(unsigned long,short)" (?ChangeMeasureType@CDCommonParamCtl@@QAE?AV?$CStringT@DV?$StrTraitMFC_DLL@DV?$ChTraitsCRT@D@ATL@@@@@ATL@@KF@Z) referenced in function "public: void __thiscall CTabConParView::CreateParamWnd(unsigned long,unsigned long,int)" (?CreateParamWnd@CTabConParView@@QAEXKKH@Z)
1>TabConParView.obj : error LNK2019: unresolved external symbol "public: class ATL::CStringT<char,class StrTraitMFC_DLL<char,class ATL::ChTraitsCRT<char> > > __thiscall CDCommonParamCtl::CreateByXML(unsigned long,class ATL::CStringT<char,class StrTraitMFC_DLL<char,class ATL::ChTraitsCRT<char> > >)" (?CreateByXML@CDCommonParamCtl@@QAE?AV?$CStringT@DV?$StrTraitMFC_DLL@DV?$ChTraitsCRT@D@ATL@@@@@ATL@@KV23@@Z) referenced in function "public: void __thiscall CTabConParView::CreateParamWnd(unsigned long,unsigned long,int)" (?CreateParamWnd@CTabConParView@@QAEXKKH@Z)
1>TabConParView.obj : error LNK2019: unresolved external symbol "public: unsigned long __thiscall CDCommonParamCtl::Create(class CWnd *,unsigned long)" (?Create@CDCommonParamCtl@@QAEKPAVCWnd@@K@Z) referenced in function "public: void __thiscall CTabConParView::CreateParamWnd(unsigned long,unsigned long,int)" (?CreateParamWnd@CTabConParView@@QAEXKKH@Z)
1>../../../../Debug/RTM\RTM_MoniDataReplyD.dll : fatal error LNK1120: 10 unresolved externals

出现这个错误的原因在于，你所使用的方法、类或组件没有加入到工程，右键工程名，选择"添加(add)"---->”已经存在的项（existing item）“。