ShouldSerialize pattern and DataContractSerializer

Question

Is there a way to get a ShouldSerialize* template working with a DataContractSerializer ?

Here is a small example:

I have a simple Person class that looks like this:

 [DataContract] public class Person { [DataMember] public string FirstName { get; set; } public bool ShouldSerializeFirstName() { return !string.IsNullOrEmpty(FirstName); } [DataMember] public string LastName { get; set; } public bool ShouldSerializeLastName() { return !string.IsNullOrEmpty(LastName); } public Person(string firstName, string lastName) { FirstName = firstName; LastName = lastName; } public Person(string firstName) { FirstName = firstName; } public Person() { } } 

FirstName or LastName must be serialized if they are not empty or empty. This works with the XmlSerializer , but the DataContractSerializer seems to ignore the ShouldSerialize pattern. *Specified template also does not work.

I am creating two different xml files. One with DataContractSerializer, one with XmlSerializer:

 List<Person> persons = new List<Person>(); persons.Add (new Person("John", "Doe")); persons.Add (new Person("Carl")); DataContractSerializer serializer = new DataContractSerializer (typeof (List<Person>)); using (XmlWriter writer = XmlWriter.Create(@"c:\test1.xml", settings)) { serializer.WriteObject (writer, persons); } XmlSerializer xmlSerializer = new XmlSerializer (typeof (List<Person>)); XmlWriter xmlWriter = XmlWriter.Create (@"c:\text2.xml", settings); xmlSerializer.Serialize (xmlWriter, persons); xmlWriter.Close(); 

The output of test1.xml (DataContractSerializer) looks like this:

 <?xml version="1.0" encoding="utf-8"?> <ArrayOfPerson xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.datacontract.org/2004/07/XmlSerialization"> <Person> <FirstName>John</FirstName> <LastName>Doe</LastName> </Person> <Person> <FirstName>Carl</FirstName> <LastName i:nil="true" /> </Person> </ArrayOfPerson> 

The output of test2.xml (XmlSerializer) is as follows:

 <?xml version="1.0" encoding="utf-8"?> <ArrayOfPerson xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Person> <FirstName>John</FirstName> <LastName>Doe</LastName> </Person> <Person> <FirstName>Carl</FirstName> </Person> </ArrayOfPerson> 

Answer 1

AFAIK, ShouldSerialize * does not work with datacontract serializer. This is useless in Kevin's answer. You can delete it. Unfortunately, the code is provided only if you are handling a null value.

Here is a more general solution: it returns a null value depending on the given condition.

  [DataContract] public class Person { private string firstName; [DataMember(IsRequired = false, EmitDefaultValue = false)] public string FirstName { get { //Put here any condition for serializing return string.IsNullOrWhiteSpace(firstName) ? null : firstName; } set { firstName = value; } } } 

Answer 2

You must set the IsRequired attribute in the DataMember:

 [DataContract] public class Person { [DataMember(IsRequired = False, EmitDefaultValue = False)] public string FirstName { get; set; } ... }