How to keep XmlSerializer from killing NewLines in Strings?

public class BinarySerialize where T : new() { public static string Serialize(T options, string path) {

            var xml = "";
            try
            {
                File.Delete(path);
            }
            catch (Exception)
            {


            }

            try
            {
                using (var fs = new FileStream(path, FileMode.Create, FileAccess.Write, FileShare.ReadWrite))
                {
                    var bf = new BinaryFormatter();


                    bf.Serialize(fs, options);
                }


            }
            catch (Exception ex)
            {

                return ex.Message;
            }



            return xml;





        }

        public static T Deserialize(string path)
        {
            T filteroptions;
            using (var fs = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read))
            {
                var bf = new BinaryFormatter();
                filteroptions = (T)bf.Deserialize(fs);
            }
            return filteroptions;

        }
    }

It is not the XmlSerializer but the XmlWriter which is removing your CR. To retain it we must have the writer convert CR to its character entity 
.

XmlWriterSettings ws = new XmlWriterSettings();
ws.NewLineHandling = NewLineHandling.Entitize;

XmlSerializer ser = new XmlSerializer( typeof( Abc ) );
using (XmlWriter wr = XmlWriter.Create( "abc.xml", ws )) {
    ser.Serialize( wr, s );
}

This is exactly the same with DataContractSerializer:

var ser = new DataContractSerializer( typeof( Abc ) );
using (XmlWriter wr = XmlWriter.Create( "abc.xml", ws )) {
    ser.Serialize( wr, s );
}

Why do we need to do this?

This is because compliant XML parsers must, before parsing, translate CRLF and any CR not followed by a LF to a single LF. This behavior is defined in the End-of-Line handling section of the XML 1.0 specification.

As this happens before parsing, you need to encode CR as its character entity if you want the CR to exist in the document.

public class SerializeAny<TF> where TF : new()
{
    public static TF Deserialize(string serializedData)
    {
        try
        {
            var xmlSerializer = new XmlSerializer(typeof(TF));
            TF collection;
            using (var xmlReader = new XmlTextReader(serializedData, XmlNodeType.Document, null))
            {
                collection = (TF)xmlSerializer.Deserialize(xmlReader);
            }
            return collection;
        }
        catch (Exception)
        {


        }

        return new TF();
    }


    public static TF DeserializeZip(string path)
    {
        try
        {
            var bytes = File.ReadAllBytes(path);

            string serializedData = Unzip(bytes);

            TF collection = Deserialize(serializedData);


            return collection;
        }
        catch (Exception)
        {


        }

        return new TF();
    }

    public static string Serialize(TF options)
    {
        var xml = "";

        try
        {
            var xmlSerializer = new XmlSerializer(typeof(TF));
            using (var stringWriter = new StringWriter())
            {
                xmlSerializer.Serialize(stringWriter, options);
                xml = stringWriter.ToString();
            }
        }
        catch (Exception ex)
        {

            return ex.Message;
        }



        return xml;
    }

    public static string SerializeZip(TF options, string path)
    {
        var xml = "";

        try
        {
            xml = Serialize(options);
            var zip = Zip(xml);
            File.WriteAllBytes(path, zip);
        }
        catch (Exception ex)
        {

            return ex.Message;
        }



        return xml;
    }



    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2202:Do not dispose objects multiple times")]
    internal static String SerializeObject<T>(T obj, Encoding enc)
    {
        using (var ms = new MemoryStream())
        {
            var xmlWriterSettings = new System.Xml.XmlWriterSettings()
            {
                // If set to true XmlWriter would close MemoryStream automatically and using would then do double dispose
                // Code analysis does not understand that. That's why there is a suppress message.
                CloseOutput = false,
                Encoding = enc,
                OmitXmlDeclaration = false,
                Indent = true
            };
            using (var xw = XmlWriter.Create(ms, xmlWriterSettings))
            {
                var s = new XmlSerializer(typeof(T));
                s.Serialize(xw, obj);
            }

            return enc.GetString(ms.ToArray());
        }
    }

    private static void CopyTo(Stream src, Stream dest)
    {
        byte[] bytes = new byte[4096];

        int cnt;

        while ((cnt = src.Read(bytes, 0, bytes.Length)) != 0)
        {
            dest.Write(bytes, 0, cnt);
        }
    }

    private static byte[] Zip(string str)
    {
        var bytes = Encoding.UTF8.GetBytes(str);

        using (var msi = new MemoryStream(bytes))
        using (var mso = new MemoryStream())
        {
            using (var gs = new GZipStream(mso, CompressionMode.Compress))
            {
                //msi.CopyTo(gs);
                CopyTo(msi, gs);
            }

            return mso.ToArray();
        }
    }

    private static string Unzip(byte[] bytes)
    {
        using (var msi = new MemoryStream(bytes))
        using (var mso = new MemoryStream())
        {
            using (var gs = new GZipStream(msi, CompressionMode.Decompress))
            {
                CopyTo(gs, mso);
            }

            return Encoding.UTF8.GetString(mso.ToArray());
        }
    }

}