pass a string from managed C# to managed C++

See more:

C++/CLI

C#

what is the preferred method to pass a string between C++ and C#?
i have a c++ class where one of the functions takes a const char *var1 and const char* var2[] as parameter.

When I call such function in C# , function accepts arguments types as sbyte*.
Just using a c#-string doesnt seem to work as the function in C# requires a sbyte* and sbyte**

C++ class:

public ref class MyClass
{
public:
	void Sample(const char * var1,const char* Var2[]);
}

C# call..

class Program
    {
        static void Main(string[] args)
        {
               MyClass oClass = new MyClass();
               string var1 = "Variable1";
               string[] var2 = {"1","2"};
               oClass.Sample(var1,var2);
        }
}

Error:

Error	1	Argument 1: cannot convert from 'string' to 'sbyte*'<br />
Error	2	Argument 2: cannot convert from 'string[]' to 'sbyte**'

So I need help in understanding how can I pass string arguments from managed C# to managed C++?

Thanks