c#System::String转c++string
#include <msclr/marshal.h>
#include <msclr/marshal_windows.h>
#include <msclr/marshal_cppstd.h>
#include <msclr/marshal_atl.t>
System::String^ pStr;//这里没有gcnew
std::string s = msclr::interop::marshal_as<std::string>(pStr->ToString())