How to rename <ArrayOf> XML attribute that generated after serializing List of objects

ilann picture ilann · Jun 27, 2010 · Viewed 21.6k times · Source

I am serializing List of objects List<TestObject> , and XmlSerializer generates <ArrayOfTestObject> attribute, I want rename it or remove it.
Can it be done with creating new class that encapsulated List as field?

 [XmlRoot("Container")]    
 public class TestObject
 {
     public TestObject() { }                         
     public string Str { get; set; }                         
 }

 List<TestObject> tmpList = new List<TestObject>();

 TestObject TestObj = new TestObject();
 TestObj.Str = "Test";

 TestObject TestObj2 = new TestObject();
 TestObj2.Str = "xcvxc";

 tmpList.Add(TestObj);
 tmpList.Add(TestObj2);


 XmlWriterSettings settings = new XmlWriterSettings();
 settings.OmitXmlDeclaration = true;
 settings.Indent = true;
 XmlSerializer serializer = new XmlSerializer(typeof(List<TestObject>));

 using (XmlWriter writer = XmlWriter.Create(@"C:\test.xml", settings))
 {              
     XmlSerializerNamespaces namespaces = new XmlSerializerNamespaces();
     namespaces.Add(string.Empty, string.Empty);
     serializer.Serialize(writer, tmpList, namespaces);                            
}


<ArrayOfTestObject>
  <TestObject>
    <Str>Test</Str>
  </TestObject>
  <TestObject>
    <Str>xcvxc</Str>
  </TestObject>
</ArrayOfTestObject>

Answer

Marc Gravell picture Marc Gravell · Jun 28, 2010

The most reliable way is to declare an outermost DTO class:

[XmlRoot("myOuterElement")]
public class MyOuterMessage {
    [XmlElement("item")]
    public List<TestObject> Items {get;set;}
}

and serialize that (i.e. put your list into another object).


You can avoid a wrapper class, but I wouldn't:

class Program
{
    static void Main()
    {
        XmlSerializer ser = new XmlSerializer(typeof(List<Foo>),
             new XmlRootAttribute("Flibble"));
        List<Foo> foos = new List<Foo> {
            new Foo {Bar = "abc"},
            new Foo {Bar = "def"}
        };
        ser.Serialize(Console.Out, foos);
    }
}

public class Foo
{
    public string Bar { get; set; }
}

The problem with this is that when you use custom attributes you need to be very careful to store and re-use the serializer, otherwise you get lots of dynamic assemblies loaded into memory. This is avoided if you just use the XmlSerializer(Type) constructor, as it caches this internally automatically.