Convert string to binary and binary to string in C#

String to binary method:

 public static string StringToBinary(string data)
 {
     StringBuilder sb = new StringBuilder();

     foreach (char c in data.ToCharArray())
     {
         sb.Append(Convert.ToString(c, ).PadLeft(, ''));
     }
     return sb.ToString();
 }

Binary to string method:

 public static string BinaryToString(string data)
 {
     List<Byte> byteList = new List<Byte>();

     for (int i = ; i < data.Length; i += )
     {
         byteList.Add(Convert.ToByte(data.Substring(i, ), ));
     }
     return Encoding.ASCII.GetString(byteList.ToArray());
 }