Read and Write Text in a file in C#.net

 string fileName = @"C:\adi.txt";
            if (!File.Exists(fileName))
            {
                string startText = "File content" + Environment.NewLine;
                lblerror.Text = startText;
                File.WriteAllText(fileName, startText);
                File.WriteAllText(fileName, "Add more content \n");
            }
            string appendText = "New appened text" + Environment.NewLine;
            File.AppendAllText(fileName, appendText);
            string data = File.ReadAllText(fileName);
            Console.WriteLine(data);