XmlSerializer - There was an error reflecting type

Question

Using C# .NET 2.0, I have a composite data class that does have the [Serializable] attribute on it. I am creating an XMLSerializer class and passi

Answer 1

I have been using the NetDataSerialiser class to serialise my domain classes. NetDataContractSerializer Class.

The domain classes are shared between client and server.

Answer 2

I recently got this in a web reference partial class when adding a new property. The auto generated class was adding the following attributes.

    [System.Xml.Serialization.XmlElementAttribute(Order = XX)]

I needed to add a similar attribute with an order one higher than the last in the auto generated sequence and this fixed it for me.

Answer 3

All the objects in the serialization graph have to be serializable.

Since XMLSerializer is a blackbox, check these links if you want to debug further into the serialization process..

Changing where XmlSerializer Outputs Temporary Assemblies

HOW TO: Debug into a .NET XmlSerializer Generated Assembly

Answer 4

I too thought that the Serializable attribute had to be on the object but unless I'm being a complete noob (I am in the middle of a late night coding session) the following works from the SnippetCompiler:

using System;
using System.IO;
using System.Xml;
using System.Collections.Generic;
using System.Xml.Serialization;

public class Inner
{
    private string _AnotherStringProperty;
    public string AnotherStringProperty 
    { 
      get { return _AnotherStringProperty; } 
      set { _AnotherStringProperty = value; } 
    }
}

public class DataClass
{
    private string _StringProperty;
    public string StringProperty 
    { 
       get { return _StringProperty; } 
       set{ _StringProperty = value; } 
    }

    private Inner _InnerObject;
    public Inner InnerObject 
    { 
       get { return _InnerObject; } 
       set { _InnerObject = value; } 
    }
}

public class MyClass
{

    public static void Main()
    {
        try
        {
            XmlSerializer serializer = new XmlSerializer(typeof(DataClass));
            TextWriter writer = new StreamWriter(@"c:\tmp\dataClass.xml");
            DataClass clazz = new DataClass();
            Inner inner = new Inner();
            inner.AnotherStringProperty = "Foo2";
            clazz.InnerObject = inner;
            clazz.StringProperty = "foo";
            serializer.Serialize(writer, clazz);
        }
        finally
        {
            Console.Write("Press any key to continue...");
            Console.ReadKey();
        }
    }

}

I would imagine that the XmlSerializer is using reflection over the public properties.

Answer 5

I was getting the same error when I created a property having a datatype - Type. On this, I was getting an error - There was an error reflecting type. I kept checking the 'InnerException' of every exception from the debug dock and got the specific field name (which was Type) in my case. The solution is as follows:

    [XmlIgnore]
    public Type Type { get; set; }

Answer 6

Most common reasons by me:

 - the object being serialized has no parameterless constructor
 - the object contains Dictionary
 - the object has some public Interface members