How to add xsi schemalocation to root c # object XmlSerializer

Question

I am using XmlSerializer to create an object representing an XML file and now i want to add a schemalocation to the rootelement of my xml file. I can add namespaces like the

Answer 1

Let's assume the following XSD:

There are two ways at least to do it. The first one relies on inheritance and how you can play with the serializer annotations.

xsd.exe generates this:

//------------------------------------------------------------------------------
// 
//     This code was generated by a tool.
//     Runtime Version:4.0.30319.18034
//
//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated.
// 
//------------------------------------------------------------------------------

using System.Xml.Serialization;

// 
// This source code was auto-generated by xsd, Version=4.0.30319.1.
// 

/// 
[System.CodeDom.Compiler.GeneratedCodeAttribute("xsd", "4.0.30319.1")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlTypeAttribute(AnonymousType=true, Namespace="http://tempuri.org/XMLSchema.xsd")]
[System.Xml.Serialization.XmlRootAttribute(Namespace="http://tempuri.org/XMLSchema.xsd", IsNullable=false)]
public partial class elementB {

    private string firstNameField;

    private string lastNameField;

    /// 
    public string FirstName {
        get {
            return this.firstNameField;
        }
        set {
            this.firstNameField = value;
        }
    }

    /// 
    public string LastName {
        get {
            return this.lastNameField;
        }
        set {
            this.lastNameField = value;
        }
    }
}

To "inject" the xsi:schemaLocation add a new class, elementA : elementB; notice:

• System.Xml.Serialization.XmlRootAttribute setup
• schemaLocation property setup.

Test program:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml.Serialization;
using System.IO;
using System.Xml;

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            elementB b = new elementB();
            b.FirstName = "P";
            b.LastName = "G";

            XmlSerializer ser = new XmlSerializer(typeof(elementB));
            StringBuilder sb = new StringBuilder();
            using (XmlWriter writer = XmlWriter.Create(sb, new XmlWriterSettings() { Indent = true })) 
            {
                ser.Serialize(writer, b);
            }
            Console.WriteLine(sb.ToString());

            elementA a = new elementA();
            a.FirstName = "P";
            a.LastName = "G";
            a.schemaLocation = "http://tempuri.org/XMLSchema.xsd me";
            ser = new XmlSerializer(typeof(elementA));
            sb = new StringBuilder();
            using (XmlWriter writer = XmlWriter.Create(sb, new XmlWriterSettings() { Indent = true }))
            {
                ser.Serialize(writer, a);
            }
            Console.WriteLine(sb.ToString());
        }
    }
}

[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlTypeAttribute(AnonymousType = true, Namespace = "http://tempuri.org/XMLSchema.xsd")]
[System.Xml.Serialization.XmlRootAttribute(Namespace = "http://tempuri.org/XMLSchema.xsd", ElementName = "elementB", IsNullable = false)]
public partial class elementA : elementB
{

    private string torefField;

    /// 
    [System.Xml.Serialization.XmlAttributeAttribute(Form = System.Xml.Schema.XmlSchemaForm.Qualified, Namespace = "http://www.w3.org/2001/XMLSchema-instance")]
    public string schemaLocation
    {
        get
        {
            return this.torefField;
        }
        set
        {
            this.torefField = value;
        }
    }
}

Generates the expected result:

  P
  G



  Petru
  Gardea

The second way relies on a custom writer that will inject what you want, wherever you want it (assuming the appropriate logic).

You implement a custom XmlWriter:

class MyXmlWriter : XmlWriter
{
    XmlWriter _writer;
    bool _docElement = true;

    public string SchemaLocation { get; set; }
    public string NoNamespaceSchemaLocation { get; set; }

    public MyXmlWriter(XmlWriter writer)
    {
        _writer = writer;
    }

    (other methods omitted)

    public override void WriteStartElement(string prefix, string localName, string ns)
    {
        _writer.WriteStartElement(prefix, localName, ns);
        if (_docElement)
        {
            if (!string.IsNullOrEmpty(SchemaLocation))
            {
                _writer.WriteAttributeString("xsi", "schemaLocation", "http://www.w3.org/2001/XMLSchema-instance", SchemaLocation);
            }
            if (!string.IsNullOrEmpty(NoNamespaceSchemaLocation))
            {
                _writer.WriteAttributeString("xsi", "noNamesapceSchemaLocation", "http://www.w3.org/2001/XMLSchema-instance", NoNamespaceSchemaLocation);
            }
            _docElement = false;
        }
    }

    (other methods omitted)

}

A modified test program:

static void Main(string[] args)
{
    elementB b = new elementB();
    b.FirstName = "P";
    b.LastName = "G";

    XmlSerializer ser = new XmlSerializer(typeof(elementB));
    StringBuilder sb = new StringBuilder();
    using (XmlWriter writer = XmlWriter.Create(sb, new XmlWriterSettings() { Indent = true })) 
    {
        ser.Serialize(writer, b);
    }
    Console.WriteLine(sb.ToString());

    sb = new StringBuilder();

    using (XmlWriter writer = XmlWriter.Create(sb, new XmlWriterSettings() { Indent = true }))
    {
        MyXmlWriter newWriter = new MyXmlWriter(writer) { SchemaLocation = "http://tempuri.org/XMLSchema.xsd me" };
        ser.Serialize(newWriter, b);
    }
    Console.WriteLine(sb.ToString());
}

The result is the same...

  P
  G



  P
  G