Creating a function to read line in C#

So far my code is as follows:

...
namespace read_file
{
    class Program
    {
        static void Main(string[] args)
        {
            TextReader namefile = new StreamReader(@"E:\Code in C Sharp\read-file\read-file\test.txt");
            string line = namefile.ReadLine();
        ...
        }

        static public string[] Returnval(string line)
        {
            var Returnval = line.Split('\t');
            return Returnval;
        }
    }   
}

I tried to add a new line to Returnval function which is as follows:

string line = namefile.Readline();

I got an error saying namefile is not in context.

Another approach:

class Program
{
    static TextReader namefile; // ***
    static void Main(string[] args)
    {
        //TextReader namefile = new StreamReader(@"E:\Code in C Sharp\read-file\read-file\test.txt");
        namefile = new StreamReader(@"E:\Code in C Sharp\read-file\read-file\test.txt"); // ***
        string line = namefile.ReadLine();
...
    }

    static public string[] Returnval(string line)
    {
        string linex = namefile.ReadLine(); // ***
        var Returnval = line.Split('\t');
        return Returnval;
    }
}

- Wayne