Populating ANY elements on a web service in C#

Question

Can someone point me to a C# example where they populate a request and receive the response for a web service where the schema is mostly implemented as ANY elements?

Answer 1

XmlNode is a type in the old XML Document Object Model that dates from c# 1.1. It has been superseded by the much easier to use LINQ to XML object model. What is not well known is that [XmlAnyElementAttribute] actually supports this API. Thus in your GenericRequestData_Type type you could manually change the Any property to be of type System.Xml.Linq.XElement[]:

public class GenericRequestData_Type
{
    private System.Xml.Linq.XElement[] anyField;

    [System.Xml.Serialization.XmlAnyElementAttribute()]
    public System.Xml.Linq.XElement[] Any
    {
        get
        {
            return this.anyField;
        }
        set
        {
            this.anyField = value;
        }
    }
}

Then you can initialize the array easily as follows, following the instructions in Creating XML Trees in C# (LINQ to XML):

// Taken from 
// https://msdn.microsoft.com/en-us/library/mt693096.aspx
var contacts =
    new XElement("Contacts",
        new XElement("Contact",
            new XElement("Name", "Patrick Hines"),
            new XElement("Phone", "206-555-0144"),
            new XElement("Address",
                new XElement("Street1", "123 Main St"),
                new XElement("City", "Mercer Island"),
                new XElement("State", "WA"),
                new XElement("Postal", "68042")
            )
        )
    );

var genericRequest = new GenericRequestData_Type();
genericRequest.Any = new[] { contacts };

Sample fiddle.

Answer 2

XmlNode is an abstract base type. You can create concrete XmlElement objects and add then to your Any array following the instructions in Create New Nodes in the DOM:

• First, create an XmlDocument. While the document does not appear explicitly in the XmlElement [] Any array, it is needed to subsequently create elements.
• Create elements using XmlDocument.CreateElement()
• Add the created elements to their parents as appropriate using XmlNode.AppendChild
• Set text values by using XmlElement.InnerText.

Thus the following will work:

var dom = new XmlDocument();
var contacts = dom.CreateElement("Contacts");
dom.AppendChild(contacts);
var contact = dom.CreateElement("Contact");
contacts.AppendChild(contact);
var name = dom.CreateElement("Name");
contact.AppendChild(name);
name.InnerText = "Patrick Hines";
var phone = dom.CreateElement("Phone");
contact.AppendChild(phone);
phone.InnerText = "206-555-0144";
var address = dom.CreateElement("Address");
contact.AppendChild(address);
var street1 = dom.CreateElement("Street1");
address.AppendChild(street1);
street1.InnerText = "123 Main St";
var city = dom.CreateElement("City");
address.AppendChild(city);
city.InnerText = "Mercer Island";
var state = dom.CreateElement("State");
address.AppendChild(state);
state.InnerText = "WA";
var postal = dom.CreateElement("Postal");
address.AppendChild(postal);
postal.InnerText = "68042";

var genericRequest = new GenericRequestData_Type();
genericRequest.Any = new[] { dom.DocumentElement };

Sample fiddle.

Answer 3

Your question is fairly general so I'm going to narrow it down a bit to the following situation: you have a type with an [XmlAnyElement] member like so:

public class GenericRequestData_Type
{
    private System.Xml.XmlElement[] anyField;

    [System.Xml.Serialization.XmlAnyElementAttribute()]
    public System.Xml.XmlElement[] Any
    {
        get
        {
            return this.anyField;
        }
        set
        {
            this.anyField = value;
        }
    }
}

And you would like to initialize the Any field to the following XML:

<Contacts>
  <Contact>
    <Name>Patrick Hines</Name>
    <Phone>206-555-0144</Phone>
    <Address>
      <Street1>123 Main St</Street1>
      <City>Mercer Island</City>
      <State>WA</State>
      <Postal>68042</Postal>
    </Address>
  </Contact>
</Contacts>

How can this be done?

There are several options, so I'll break it down into a few different answers.

Firstly, you could design c# classes corresponding to your desired XML using a code-generation tool such as http://xmltocsharp.azurewebsites.net/ or Visual Studio's Paste XML as Classes. Then you can serialize those classes directly to an XmlNode hierarchy using XmlSerializer combined with XmlDocument.CreateNavigator().AppendChild().

First, introduce the following extension methods:

public static class XmlNodeExtensions
{
    public static XmlDocument AsXmlDocument<T>(this T o, XmlSerializerNamespaces ns = null, XmlSerializer serializer = null)
    {
        XmlDocument doc = new XmlDocument();
        using (XmlWriter writer = doc.CreateNavigator().AppendChild())
            new XmlSerializer(o.GetType()).Serialize(writer, o, ns ?? NoStandardXmlNamespaces());
        return doc;
    }

    public static XmlElement AsXmlElement<T>(this T o, XmlSerializerNamespaces ns = null, XmlSerializer serializer = null)
    {
        return o.AsXmlDocument(ns, serializer).DocumentElement;
    }

    public static T Deserialize<T>(this XmlElement element, XmlSerializer serializer = null)
    {
        using (var reader = new ProperXmlNodeReader(element))
            return (T)(serializer ?? new XmlSerializer(typeof(T))).Deserialize(reader);
    }

    /// <summary>
    /// Return an XmlSerializerNamespaces that disables the default xmlns:xsi and xmlns:xsd lines.
    /// </summary>
    /// <returns></returns>
    public static XmlSerializerNamespaces NoStandardXmlNamespaces()
    {
        var ns = new XmlSerializerNamespaces();
        ns.Add("", ""); // Disable the xmlns:xsi and xmlns:xsd lines.
        return ns;
    }
}

public class ProperXmlNodeReader : XmlNodeReader
{
    // Bug fix from this answer https://stackoverflow.com/a/30115691/3744182
    // To http://stackoverflow.com/questions/30102275/deserialize-object-property-with-stringreader-vs-xmlnodereader
    // By https://stackoverflow.com/users/8799/nathan-baulch
    public ProperXmlNodeReader(XmlNode node) : base(node) { }

    public override string LookupNamespace(string prefix)
    {
        return NameTable.Add(base.LookupNamespace(prefix));
    }
}

Next, define types corresponding to your <Contacts> hierarchy:

[XmlRoot(ElementName = "Address")]
public class Address
{
    [XmlElement(ElementName = "Street1")]
    public string Street1 { get; set; }
    [XmlElement(ElementName = "City")]
    public string City { get; set; }
    [XmlElement(ElementName = "State")]
    public string State { get; set; }
    [XmlElement(ElementName = "Postal")]
    public string Postal { get; set; }
}

[XmlRoot(ElementName = "Contact")]
public class Contact
{
    [XmlElement(ElementName = "Name")]
    public string Name { get; set; }
    [XmlElement(ElementName = "Phone")]
    public string Phone { get; set; }
    [XmlElement(ElementName = "Address")]
    public Address Address { get; set; }
}

[XmlRoot(ElementName = "Contacts")]
public class Contacts
{
    [XmlElement(ElementName = "Contact")]
    public Contact Contact { get; set; }
}

[XmlRoot("GenericRequestData_Type")]
public class Person
{
    public string Name { get; set; }
    public DateTime BirthDate { get; set; }
    [XmlArray("Emails")]
    [XmlArrayItem("Email")]
    public List<string> Emails { get; set; }
    [XmlArray("Issues")]
    [XmlArrayItem("Id")]
    public List<long> IssueIds { get; set; }
}

Finally, initialize your GenericRequestData_Type as follows:

var genericRequest = new GenericRequestData_Type();

var contacts = new Contacts
{
    Contact = new Contact
    {
        Name = "Patrick Hines",
        Phone = "206-555-0144",
        Address = new Address
        {
            Street1 = "123 Main St",
            City = "Mercer Island",
            State = "WA",
            Postal = "68042",
        },
    }
};
genericRequest.Any = new[] { contacts.AsXmlElement() };

Sample fiddle.