Solution 1:

Here is a very simple way to do this in code w/o having to worry about buffer lengths. Only use this solution if you are certain you are dealing with ASCII:

Platform::String^ fooRT = "aoeu";
std::wstring fooW(fooRT->Begin());
std::string fooA(fooW.begin(), fooW.end());
const char* charStr = fooA.c_str();

Keep in mind that in this example, the char* is on the stack and will go away once it leaves scope

Solution 2:

Platform::String::Data() will return a wchar_t const* pointing to the contents of the string (similar to std::wstring::c_str()). Platform::String represents an immutable string, so there's no accessor to get a wchar_t*. You'll need to copy its contents, e.g. into a std::wstring, to make changes.

There's no direct way to get a char* or a char const* because Platform::String uses wide characters (all Metro style apps are Unicode apps). You can convert to multibyte using WideCharToMultiByte.

Solution 3:

You shouldn't cast a wide character to a char, you will mangle languages using more than one byte per character, e.g. Chinese. Here is the correct method.

#include <cvt/wstring>
#include <codecvt>

Platform::String^ fooRT = "foo";
stdext::cvt::wstring_convert<std::codecvt_utf8<wchar_t>> convert;
std::string stringUtf8 = convert.to_bytes(fooRT->Data());
const char* rawCstring = stringUtf8.c_str();