👀 Views: 1 💬 Answers: 1 📅 Created: 2025-06-11

c# xml serialization polymorphism C#

Quick question that's been bugging me - I'm working on a project and hit a roadblock... I'm experiencing unexpected behavior when trying to serialize and deserialize an XML representation of a class hierarchy using `XmlSerializer` in C# 8.0. I have a base class `Animal` and a derived class `Dog`. The serialization works correctly, but when deserializing, I consistently get an `InvalidOperationException` with the message 'There is an behavior in XML document (1, 2)'. I've tried specifying the `XmlInclude` attribute on the base class, but the scenario continues. My classes are defined as follows: ```csharp [XmlInclude(typeof(Dog))] public class Animal { public string Name { get; set; } } public class Dog : Animal { public string Breed { get; set; } } ``` I serialize the `Dog` instance like this: ```csharp var dog = new Dog { Name = "Rex", Breed = "Labrador" }; var serializer = new XmlSerializer(typeof(Animal)); using (var writer = new StringWriter()) { serializer.Serialize(writer, dog); string xml = writer.ToString(); // XML output is valid } ``` However, when I try to deserialize: ```csharp string xml = "<Animal><Name>Rex</Name><Breed>Labrador</Breed></Animal>"; var serializer = new XmlSerializer(typeof(Animal)); using (var reader = new StringReader(xml)) { var deserializedDog = (Animal)serializer.Deserialize(reader); } ``` This throws the `InvalidOperationException`. The XML representation includes a property (`Breed`) that does not exist on the base class. What am I missing here? Is there a specific way to handle polymorphic serialization/deserialization in `XmlSerializer` that I'm overlooking? This is part of a larger web app I'm building. Any ideas what could be causing this? Am I missing something obvious?