Thread: textwriter.close deletes my data

hey,

i got this weird problem.
i am making a little textediting program and somehow when i have written a txt file and close it via:

tc.Close();

the text file goes blank. nothing left.

the code ( sorry if it looks like rubbish. i just started programming in C#) :

Code:

 static void opentxtfile(string input)
        {
            Console.Clear();
            if (input == " ")
            {
                Console.WriteLine("TEXTEDITOR \n \nGive the name of the text file, or 1 to exit\n\n");
                Console.Write("file:   ");
                string input2 = Console.ReadLine();
                Thread.Sleep(1);
                if (input2 == "1" )
                {
                    txtedit();
                    return;
                }
                else
                opentxtfile(input2);
                return;
            }
            else
            Thread.Sleep(1);
            if (!File.Exists(MAINDIR + "\\documents\\text\\" + input + ".txt"))
            {
                Console.WriteLine("text file does not exist.");
                txtedit();
                return;
            }
            TextReader tw = new StreamReader(MAINDIR + "\\documents\\text\\" + input + ".txt");
            Int32 NumberOfLines = 1;
            


           
            Thread.Sleep(1);
            using (StreamReader r = new StreamReader(MAINDIR + "\\documents\\text\\" + input + ".txt"))
            {
                int i = 0;
                while (r.ReadLine() != null) { i++; }
                NumberOfLines = i + 1;
                
            }
           
            string[] ListLines = new string[NumberOfLines+1];
            for (int i = 1; i < NumberOfLines; i++)
            {
                ListLines[i] = tw.ReadLine();
            }
            
            Console.Clear();
            for (int y = 1; y < NumberOfLines; y++)
            {
                Console.WriteLine(ListLines[y]);
            }
            tw.Close();
            Thread.Sleep(1);
            string newline = Console.ReadLine();

            TextWriter tc = new StreamWriter (MAINDIR + "\\documents\\text\\" + input + ".txt");

            if (newline != "/quit")
            {

                Thread.Sleep(5);
                int a;
                for (a = 1; a < NumberOfLines; a++)
                {
                    tc.WriteLine(ListLines[a]);
                }
                Thread.Sleep(5);
                ListLines[NumberOfLines] = newline;
                tc.WriteLine(ListLines[NumberOfLines]);
                tc.Close();
                Thread.Sleep(5);
                opentxtfile(input);
                return;
            }
            else
            tc.Close(); //  right here 
            Thread.Sleep(500);
            txtedit();
            return;
            
        }