VS2019+QT ERROR：LNK2001 public: virtual struct QMetaObject const

网上随便找了一个QT的小程序源码，编译时报错，

严重性	代码	说明	项目	路径	文件	行	禁止显示状态
错误	LNK2001	无法解析的外部符号 "public: virtual struct QMetaObject const * __cdecl MainWindow::metaObject(void)const " (?metaObject@MainWindow@@UEBAPEBUQMetaObject@@XZ)	EasyOCRApp	E:\vQt\EasyOCRApp\EasyOCRApp	E:\vQt\EasyOCRApp\EasyOCRApp\mainwindow.obj	1	
错误	LNK2001	无法解析的外部符号 "public: virtual void * __cdecl MainWindow::qt_metacast(char const *)" (?qt_metacast@MainWindow@@UEAAPEAXPEBD@Z)	EasyOCRApp	E:\vQt\EasyOCRApp\EasyOCRApp	E:\vQt\EasyOCRApp\EasyOCRApp\mainwindow.obj	1	
错误	LNK2001	无法解析的外部符号 "public: virtual int __cdecl MainWindow::qt_metacall(enum QMetaObject::Call,int,void * *)" (?qt_metacall@MainWindow@@UEAAHW4Call@QMetaObject@@HPEAPEAX@Z)	EasyOCRApp	E:\vQt\EasyOCRApp\EasyOCRApp	E:\vQt\EasyOCRApp\EasyOCRApp\mainwindow.obj	1	
错误	LNK2001	无法解析的外部符号 "public: static struct QMetaObject const MainWindow::staticMetaObject" (?staticMetaObject@MainWindow@@2UQMetaObject@@B)	EasyOCRApp	E:\vQt\EasyOCRApp\EasyOCRApp	E:\vQt\EasyOCRApp\EasyOCRApp\mainwindow.obj	1	
错误	LNK1120	4 个无法解析的外部命令	EasyOCRApp	E:\vQt\EasyOCRApp\x64\Debug	E:\vQt\EasyOCRApp\x64\Debug\EasyOCRApp.exe	1

原因是qmake没有执行相应的moc指令。

问题是：要怎样才能让vs2019调用qmake呢？我查了一下，每一个QT继承类我都加了Q_OBJECT关键字，而VS2019在编译时并没有报错，只是在链接时报错；项目是vs的Qt工具创建的，配置应该也没有错。

在stackoverflow上找到一个贴子，具体可以参考附录，给了我一些提示。

解决办法：

把所以有头文件添加到c++项目。

这一点和普通的vs c++项目不一样，vs不对项目外的C++头文件进行编译，只是引用。

附录：

Unresolved symbols QMetaObject when building OpenCV with QT support - Stack Overflow

The Qt MOC (meta-object compiler) is not being run on your Qt class files.

Since you're building from the OpenCV release, I'm assuming that the UI classes already have a Q_OBJECT line within the class declaration.

To generate a .vcproj file that has the necessary build instructions to run MOC, run this command:

qmake -tp vc -r 

If that doesn't work, right-click one of the .h files that contains a Qt class. Under Properties->Custom Build Step->General, you should see something like:

Command Line "$(QTDIR)\bin\moc.exe" -I".\GeneratedFiles\." -I"$(QTDIR)\include\." -I".\GeneratedFiles$(ConfigurationName)\." -I"$(QTDIR)\include\QtCore\." -I"$(QTDIR)\include\QtGui\." .\GeneratedFiles$(ConfigurationName)\moc_$(InputName).cpp" "-fstdafx.h" "-f[YourQtFile.h]"
Description Moc'ing $(InputFileName)...
Outputs ".\GeneratedFiles$(ConfigurationName)\moc_$(InputName).cpp"
Additional Dependencies "$(QTDIR)\bin\moc.exe";$(InputPath)

另一位回答者给出了一些图，所以我截了个滚屏，如下，