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?

I have added a web service reference to my project. The WSDL/schema for the web service has most of the body of the service request and response as an 'ANY' element. I know the underlying schema based on implementing a client to this web service request in Java. Thanks in advance for help.

ServiceGenericRequest_Type requestBody = <init>
GenericRequestData_Type genericRequest = <init>;

// here is where the ANY element starts
genericRequest.Any = new System.Xml.XmlElement[1];

// receive error that I can not create abstract type
System.Xml.XmlNode inqNode = new System.Xml.XmlNode();

genericRequest.Any[0].AppendChild(inqNode);`

Your question may be too broad for stackoverflow. What have you tried so far? Can you share some initial code? Do you have auto-generated classes you want to populate, that consist mainly of `public System.Xml.XmlElement[] Any` arrays? If so, maybe see [`How to initialize XmlElement[]?`](http://stackoverflow.com/a/32900890/3744182). — dbc, Feb 08 '17 at 13:43

dbc · Accepted Answer · 2020-01-29T09:45:22.910

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.

dbc · Answer 2 · 2017-02-08T20:51:38.550

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.

`First, create an XmlDocument... ` Proxy code generated from a WSDL doesn't have an XML document until its hitting the wire. — StingyJack, Sep 08 '17 at 02:53
@StingyJack - it doesn't have to be the same `XmlDocument` used during serialization when hitting the wire. It can be a temp `XmlDocument` made up on the fly. It needs to be constructed to manufacture the `XmlElement` objects inside the `XmlElement[]` array. — dbc, Sep 08 '17 at 18:24

dbc · Answer 3 · 2020-01-29T09:41:05.587

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.

Populating ANY elements on a web service in C#

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