boost.property_tree读取中文乱码问题

#include "boost/program_options/detail/utf8_codecvt_facet.hpp"

int test()
{
std::wifstream f(L"测试.xml");
std::locale utf8Locale(std::locale(),new boost::program_options::detail::utf8_codecvt_facet());
f.imbue(utf8Locale);

if(f)
{
boost::property_tree::read_xml(f,pt);
std::wstring text = pt.get(L"test",L"");
MessageBox(NULL,text.c_str(),L"",MB_OK);
}
}