How to convert ReadOnlyCollection class data to xml data

public static string Serialize(object dataToSerialize)     {         if(dataToSerialize==null) return null;          using (StringWriter stringwriter = new System.IO.StringWriter())         {             var serializer = new XmlSerializer(dataToSerialize.GetType());             serializer.Serialize(stringwriter, dataToSerialize);             return stringwriter.ToString();         }     }      public static T Deserialize<T>(string xmlText)     {         if(String.IsNullOrWhiteSpace(xmlText)) return default(T);          using (StringReader stringReader = new System.IO.StringReader(xmlText))         {             var serializer = new XmlSerializer(typeof(T));             return (T)serializer.Deserialize(stringReader);         }     }