How to implement Xml Serialization with inherited classes in C#

Question

I have two classes : base class name Component and inheritd class named DBComponent

[Serializable]
public class Component
{
    private string name = strin         


        

Answer 1

Unfortunately, you need to tell the XmlSerializer the classes you intend to serialize or deserialize using the XmlArrayItem() attribute. Each different type also needs its own element name. For example:

public class ComponentDerviedClass1: Component
public class ComponentDerivedClass2: Component
public class ComponentDerivedClass3: Component

// ...

public class ComponentsCollection
{
    [XmlArray("Components")]
    [XmlArrayItem("ComponentDerivedClass1", typeof(ComponentDerivedClass1))]
    [XmlArrayItem("ComponentDerivedClass2", typeof(ComponentDerivedClass2))]
    [XmlArrayItem("ComponentDerivedClass3", typeof(ComponentDerivedClass3))]
    public List<Component> Components
    {
        // ...
    }
}

This would read an XML file like:

<?xml version="1.0" encoding="utf-8" ?>
<ComponentsCollection>    
  <Components>
     <ComponentDerivedClass1>
         <!-- ... -->
     </ComponentDerivedClass1>
     <ComponentDerivedClass2>
         <!-- ... -->
     </ComponentDerivedClass2>
     <ComponentDerivedClass3>
         <!-- ... -->
     </ComponentDerivedClass3>
   </Components>  
</ComponentsCollection>

Multiple instances of each element can be present (or none).

Answer 2

Two options for different scenrios: tell the base-class

[XmlInclude(typeof(DBComponent))]
public class Component
{
    private string name = string.Empty;
    private string description = string.Empty;  
}

Or: tell the collection:

[XmlArray]
[XmlArrayItem("Component", typeof(Component))]
[XmlArrayItem("DBComponent", typeof(DBComponent))]
public List<Component> Components {...}

Actually, you can also use [XmlElement(...)] in place of [XmlArrayItem] if you don't want the outer node (Components). Also: you don't need [Serializable].