Problems serializing a class to XML and including a CDATA section

Question

I have a class that is serialized into XML for consumption by a web service. In this classes instance the XML must include a CDATA section for the web service to read it but I am at a loss on how to implement this.

The XML needs to look like:

<UpdateOrderStatus> 
    <Action>2</Action> 
        <Value> 
            <![CDATA[ 
                <Shipment> 
                    <Header> 
                        <SellerID>
                            ...
             ]]>
         </Value>
 </UpdateOrderStatus>

I am able to generate the appropriate XML, except for the CDATA part.

My class structure looks like:

public class UpdateOrderStatus
{
    public int Action { get; set; }


    public ValueInfo Value { get; set; }

    public UpdateOrderStatus()
    {
        Value = new ValueInfo();
    }


    public class ValueInfo
    {
        public ShipmentInfo Shipment { get; set; }

        public ValueInfo()
        {
            Shipment = new ShipmentInfo();
        }

        public class ShipmentInfo
        {
            public PackageListInfo PackageList { get; set; }
            public HeaderInfo Header { get; set; }
            public ShipmentInfo()
            {
                PackageList = new PackageListInfo();
                Header = new HeaderInfo();
            }

         ....

I have seen some suggestions on using:

[XmlElement("node", typeof(XmlCDataSection))]

but that causes an exception

I have also tried

 [XmlElement("Value" + "<![CDATA[")]

but the resulting XML is incorrect showing

 <Value_x003C__x0021__x005B_CDATA_x005B_>
 ....
 </Value_x003C__x0021__x005B_CDATA_x005B_>

Can anyone show me what I am doing wrong, or where I need to go with this?

--Edit--

making shipmentInfo serializable per carlosfigueira works for the most part, however I get extra ? characters in the resulting XML ( see post Writing an XML fragment using XmlWriterSettings and XmlSerializer is giving an extra character for details )

As such I changed the Write XML method to:

public void WriteXml(XmlWriter writer)
        {
            using (MemoryStream ms = new MemoryStream())
            {
                XmlSerializerNamespaces ns = new XmlSerializerNamespaces();
                ns.Add("", "");

                XmlWriterSettings settings = new XmlWriterSettings();

                settings.OmitXmlDeclaration = true;
                settings.Encoding = new UnicodeEncoding(bigEndian: false, byteOrderMark: false);
                settings.Indent = true;

                using (XmlWriter innerWriter = XmlWriter.Create(ms, settings))
                {
                    shipmentInfoSerializer.Serialize(innerWriter, this.Shipment,ns);
                    innerWriter.Flush();
                    writer.WriteCData(Encoding.UTF8.GetString(ms.ToArray()));
                }
            }
        }

However I am not getting an exception:

System.InvalidOperationException: There was an error generating the XML document. ---> System.ArgumentException: '.', hexadecimal
value 0x00, is an invalid character.

--Edit --

The exception was caused by the inclusion of my previous serializeToString method. Since removing that the CDATA output is correct, except for a spacing issue, but I am also getting a namespace and xml declaration that should be removed by the XML settings specified. Output is:

<?xml version="1.0"?>
<UpdateOrderStatus xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Action>1</Action>
  <Value><![CDATA[< S h i p m e n t I n f o >
     < P a c k a g e L i s t >
         < P a c k a g e >
             < S h i p D a t e > 2 0 1 2 - 0 7 - 1 3 T 1 1 : 5 8 : 5 1 . 0 9 2 5 6 1 5 - 0 4 : 0 0 < / S h i p D a t e >
             < I t e m L i s t >
                 < I t e m >
                     < S h i p p e d Q t y > 0 < / S h i p p e d Q t y >
                 < / I t e m >
             < / I t e m L i s t >
         < / P a c k a g e >
     < / P a c k a g e L i s t >
     < H e a d e r >
         < S e l l e r I d > S h i p m e n t   h e a d e r < / S e l l e r I d >
         < S O N u m b e r > 0 < / S O N u m b e r >
     < / H e a d e r >
 < / S h i p m e n t I n f o > ]]></Value>
</UpdateOrderStatus>

Any ideas of avoiding the BOM using the new class?

--Edit 3 -- SUCCESS!

I have implemented changes suggested below and now have the following writer class and test methods:

 UpdateOrderStatus obj = new UpdateOrderStatus();

        obj.Action = 1;
        obj.Value = new UpdateOrderStatus.ValueInfo();
        obj.Value.Shipment = new UpdateOrderStatus.ValueInfo.ShipmentInfo();
        obj.Value.Shipment.Header.SellerId = "Shipment header";
        obj.Value.Shipment.PackageList = new UpdateOrderStatus.ValueInfo.ShipmentInfo.PackageListInfo();
        obj.Value.Shipment.PackageList.Package = new UpdateOrderStatus.ValueInfo.ShipmentInfo.PackageListInfo.PackageInfo();
        obj.Value.Shipment.PackageList.Package.ShipDate = DateTime.Now;



        XmlSerializerNamespaces ns = new XmlSerializerNamespaces();
        ns.Add("", "");
        XmlWriterSettings settings = new XmlWriterSettings();
        settings.OmitXmlDeclaration = true;
        settings.Encoding = new UTF8Encoding(false);
        settings.Indent = true;
        XmlSerializer xs = new XmlSerializer(typeof(UpdateOrderStatus));
        MemoryStream ms = new MemoryStream();


        XmlWriter writer = XmlWriter.Create(ms, settings);
        xs.Serialize(writer, obj, ns);
        Console.WriteLine(Encoding.UTF8.GetString(ms.ToArray()));
    }


public void WriteXml(XmlWriter writer)
        {

            XmlSerializerNamespaces ns = new XmlSerializerNamespaces();
            ns.Add("", "");

            XmlWriterSettings settings = new XmlWriterSettings();

            settings.OmitXmlDeclaration = true;
            settings.Indent = true;

            StringBuilder sb = new StringBuilder();
            using (XmlWriter innerWriter = XmlWriter.Create(sb, settings))
            {
                shipmentInfoSerializer.Serialize(innerWriter, this.Shipment, ns);
                innerWriter.Flush();
                writer.WriteCData(sb.ToString());
            }   
        }

This produces the following XML:

<UpdateOrderStatus>
  <Action>1</Action>
  <Value><![CDATA[<ShipmentInfo>
  <PackageList>
    <Package>
      <ShipDate>2012-07-13T14:05:36.6170802-04:00</ShipDate>
      <ItemList>
        <Item>
          <ShippedQty>0</ShippedQty>
        </Item>
      </ItemList>
    </Package>
  </PackageList>
  <Header>
    <SellerId>Shipment header</SellerId>
    <SONumber>0</SONumber>
  </Header>
</ShipmentInfo>]]></Value>
</UpdateOrderStatus>

Answer 1

In response to the 'spaces' you are seeing after your edit, it is because of the encoding you are using (Unicode, 2 bytes per character).

Try:

settings.Encoding = new Utf8Encoding(false);

EDIT:

Also, note that format of the MemoryStream is not necessarily a valid UTF-8 encoded string! You can use a StringBuilder instead of MemoryStream to create your inner writer.

    public void WriteXml(XmlWriter writer)   
    {   
        XmlSerializerNamespaces ns = new XmlSerializerNamespaces();   
        ns.Add("", "");   

        XmlWriterSettings settings = new XmlWriterSettings();   

        settings.OmitXmlDeclaration = true;   
        settings.Indent = true;   

        StringBuilder sb = new StringBuilder();
        using (XmlWriter innerWriter = XmlWriter.Create(sb, settings))   
        {   
            shipmentInfoSerializer.Serialize(innerWriter, this.Shipment,ns);   
            innerWriter.Flush();   
            writer.WriteCData(sb.ToString());   
        }   
    }