C#

private void TcpListenerDataReadAsyncCallback(IAsyncResult ar)
{
TcpClient tc = (TcpClient)ar.AsyncState;
NetworkStream ns = tc.GetStream();

//read all client data

ns.Close();
tc.Close();
}

var lineCount = 1;
           using (var reader = File.OpenText(@"saved.bingo"))
           {
               while (reader.ReadLine() != null)
               {
                   lineCount++;
               }
           }


               TextWriter saveCalled = new StreamWriter("saved.bingo");
               saveCalled.Write(called.Text);
               saveCalled.Close();

               TextReader loadSaved = new StreamReader("saved.bingo");
               string saved = loadSaved.ReadToEnd();
               loadSaved.Close();

               randomGenerated.generate();

               TextReader nextBingo = new StreamReader("bingoNext.bingo");
               string bingoNum = nextBingo.ReadToEnd();
               nextBingo.Close();

               bingoNum = bingoNum.Trim();

               if (saved.Contains(bingoNum) == true)
               {
                   randomGenerated.generate();
               }
               else
               {
                   TextReader tr = new StreamReader("saved.bingo");
                   string saveNm = tr.ReadToEnd();
                   tr.Close();

                   int saveNum = saveNm.Count();

                   if (saveNum >= 15)
                   {
                       button1.Visible = false;
                       MessageBox.Show("Game Over.");
                   }

                   newnum.Text = bingoNum;

                   TextReader nextCalled = new StreamReader("calledNext.bingo");
                   string calledNum = nextCalled.ReadToEnd();
                   nextCalled.Close();

                   called.Text = calledNum;
               }

namespace openBingo
{
    public class randomGenerated
    {
        public static void generate()
        {
            System.Random linegrab = new System.Random(DateTime.Now.Millisecond);

            TextReader numRead = new StreamReader("numbers.bingo");

            ArrayList lines = new ArrayList();

            string line;

            while ((line = numRead.ReadLine()) != null)
            {
                lines.Add(line);
            }

            int randomIndex = linegrab.Next(lines.Count);


            string bingoNum = (lines[randomIndex]).ToString();

            numRead.Close();

            TextReader numbCheck = new StreamReader("saved.bingo");
            string saved = numbCheck.ReadToEnd();

            saved = saved.Trim();

            numbCheck.Close();



            if (saved.Contains(bingoNum))
            {
                randomGenerated.generate();  
            }
            else
            {
                TextWriter saveNum = new StreamWriter("saved.bingo");
                saveNum.WriteLine(bingoNum);
                saveNum.Close();

                string randBingo = bingoNum;

                TextWriter subNum = new StreamWriter("bingoNext.bingo");
                subNum.WriteLine(randBingo);
                subNum.Close();

                string newCalled = saved + " " + randBingo;
                

                TextWriter subCol = new StreamWriter("calledNext.bingo");
                subCol.WriteLine(newCalled);
                subCol.Close();
            }
        }
    }
}