XmlRootAttribute.IsNullable Property

 

Gets or sets a value that indicates whether the XmlSerializer must serialize a member that is set to null into the xsi:nil attribute set to true.

Namespace:   System.Xml.Serialization
Assembly:  System.Xml (in System.Xml.dll)

public bool IsNullable { get; set; }

Property Value

Type: System.Boolean

true if the XmlSerializer generates the xsi:nil attribute; otherwise, false.

The XML schema specification for structures allows an XML document to explicitly signal that an element's content is missing. Such an element contains the attribute xsi:nil set to true. For more information, see the http://www.w3.org/TR/xmlschema-1/ specification named XML Schema Part 1: Structures.

If the IsNullable property is set to true, the xsi:nil attribute is generated as shown in the following XML:

<?xml version="1.0" encoding="utf-8"?>
<Group xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xmlns:xsd="http://www.w3.org/2001/XMLSchema" xsi:nil="true" />

If the IsNullable property is false, an empty element is created as shown in the following code:

<?xml version="1.0" encoding="utf-8"?>
<Group xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xmlns:xsd="http://www.w3.org/2001/XMLSchema" />

The following example serializes a class named Group. The example applies the XmlRootAttribute to the class, and sets the IsNullable property to false.

using System;
using System.IO;
using System.Xml.Serialization;
using System.Xml;

// Apply the XmlRootAttribute and set the IsNullable property to false.
[XmlRoot(IsNullable = false)]
public class Group
{   
   public string Name;
}   


public class Run
{
   public static void Main()
   {
   Console.WriteLine("Running");
      Run test = new Run();
      test.SerializeObject("NullDoc.xml");

   }

   public void SerializeObject(string filename)
   {
      XmlSerializer s = new XmlSerializer(typeof(Group));

      // Writing the file requires a TextWriter.
      TextWriter writer = new StreamWriter(filename);

      // Create the object to serialize.
      Group mygroup = null;

      // Serialize the object, and close the TextWriter.
      s.Serialize(writer, mygroup);
      writer.Close();
   }
}

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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