wstringstream to TextBlock?

Question

How is it possible to convert a wstringstream so that I can display the text in a TextBlock;

I know that I can convert  wstringstream to a  wstring.

But how can I convert the  wstring to a Platform::String^ 

Or is there a way to directly write the wstring into the textbox (without using the stupid  Platform::String^ )

std::wstringstream temp;

temp << "Some text";

std::wstring testest = temp.str();