Link error with String::fromWCharArray (Unresolved symbol)

I recently upgraded my project to Qt 5.0.0, and after fixing up some compile errors, i finally got it to compile successfully, only to get this link error: unresolved external symbol “__declspec(dllimport) public: static class QString __cdecl QString::fromWCharArray(unsigned short const *,int)” (__imp_?fromWCharArray@QString@@SA?AV1@PBGH@Z) After googling, i found some answers. But i checked and i have set “Treat wchar_t as built in type” to “no”. And i have added Qt5Core.lib/Qt5Cored.lib to the linker. So i don’t know what else to do.