Use string type for a Visual Studio (V100 toolset) project

[Opariti]

Hi,
I'm using Visual Studio 2010 Professional - yes, quite old, but I am obliged to use it. The build toolset is marked as V100.
I create a C++ empty project, with, for the beginning, just <Windows.h> to include. It was supposed that I then add the necessary libraries files so that to make the code buildable.
Just for info, the scope of the project is to create a dll and call it in C#. Everything goes fine with one exception, and I didn't find the solution: it's about the 'string' type. If I define as 'string' a variable in C++ it is not recognized. I have tried with 'using namespace std;' but got the error that 'std' is not recognized either.
I have used 'char *' instead and it works when marshalling to C#. The need to use 'string' appears when I want to export a C++ class to C# and the C++ constructor called in C# must instantiate a 'string'. I've tried all kinds of C# and C++ methods and functions, I'm not happy with the result or the complexity.
Therefore, how can I, for the given development environment - VS2010, C++, empty project - have access to a 'string' type?
Thanks

[Thomas1965]

You have to include <string> before using namespace std;

The need to use 'string' appears when I want to export a C++ class to C# and the C++ constructor called in C# must instantiate a 'string'.

Why can't the constructor take a char* ?
Why don't you use a dll project in VS ?
Why don't you use C++/CLI , it would be much easier to use in C# ?

Sorry for being so curious, but it seems you make your live more difficult than neccessery.

[Opariti]

Thanks Thomas,
I've solved my issue which was in fact related to marshalling an alphanumeric variable from C++ to C#, and did it through a C# IntPtr container. My initial assumptions where wrong, in fact using char* in C++ is the best by far.