deserialize xml to list

Question

I have searched forever tryng to figure out what I am doing wrong in trying to deseralize some xml to a list. I am able to get the deserailzation of eveything but the answers, so the deserailization is working but it appears I am missing something on the class decorations. The answers show in the "testObj", but are null.

Any help is appreciated.

Sample Xml

<?xml version="1.0" encoding="utf-8" ?>
<TestObj xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<question>
    <stem>this is the question stem</stem>
    <answers>
      <answer>answer 1</answer>
      <answer>answer 2</answer>
      <answer>answer 3</answer>
      <answer>answer 4</answer>
 </question>
 <question .... </question>
 <question .... </question>
 <question .... </question>
</TestObj>

[Serializable]
    public class TestObj
    {
        [XmlElement(ElementName = "question")]
        [XmlElement(typeof(QuestionObj))]
        public List<QuestionObj> Questions { get; set; }

        public int Id { get; set; }
        public string Name;
    }

[Serializable]
    public class QuestionObj
    {
        [XmlElement(ElementName = "stem")]
        public string Stem { get; set; }


        [XmlArray("answers")]
        [XmlArrayItem(ElementName = "answer")]
        [XmlArrayItem(typeof(AnswerObj))]
        public List<AnswerObj> Answers { get; set; }

        public int TestId { get; set; }
        public int Id { get; set; }
    }

[Serializable]
   public class AnswerObj
    {
        [XmlElement(ElementName = "answer")]
        public string Answer { get; set; }

       public int Id { get; set; }
       public int StemId { get; set; }
    }

Object returned:
Question:this is the question stem
   answers
      answer:null
      answer null;
etc

what do you use for deserialization? – esskar Nov 28 '11 at 16:49 — esskar, Nov 28 '11 at 16:49
Should those answering assume a closing tag for `` or not? – Austin Salonen Nov 28 '11 at 16:54 — Austin Salonen, Nov 28 '11 at 16:54

score 2 · Accepted Answer · answered Nov 28 '11 at 16:57

2

Your serialization attributes are making the serializer look for an xml structure like this:

<question>
  <answers>
    <answer>
      <answer>answer text</answer>
      <Id>1234</Id>
      <StemId>1234</StemId>
    </answer>
  </answers>
</question>

You can either change the serializer to use a List<string> for the answers or construct an AnswerObj in xml for each answer (as per above).

answered Nov 28 '11 at 16:57

Balthy

866
6
3

Thanks - this was the problem, just took me forever to see it - it seems I can't award points because my reputatio is no high enough – user1069733 Nov 28 '11 at 18:38

score 1 · Answer 2 · edited May 23 '17 at 10:33

Here's a good example from Marc Gravell here:

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

[XmlRoot("user_list")]
public class UserList
{
    public UserList() {Items = new List<User>();}

    [XmlArray("Items")]
    [XmlArrayItem("User", typeof(User))]
    public List<User> Items {get;set;}
}
public class User
{
    [XmlElement("id")]
    public Int32 Id { get; set; }

    [XmlElement("name")]
    public String Name { get; set; }
}

static class Program
{
    static void Main()
    {
        XmlSerializer ser= new XmlSerializer(typeof(UserList));
        UserList list = new UserList();
        list.Items.Add(new User { Id = 1, Name = "abc"});
        list.Items.Add(new User { Id = 2, Name = "def"});
        list.Items.Add(new User { Id = 3, Name = "ghi"});
        ser.Serialize(Console.Out, list);
    }
}

This is a great example of serialization - but doesn't show why my deserialisation is not working - when using this model answers only shows 1 answer - any suggestions? — user1069733, Nov 28 '11 at 17:07
Try using the `XmlArray` or `XmlArrayItem` attribute instead. — James Johnson, Nov 28 '11 at 17:18

score 0 · Answer 3 · answered Nov 28 '11 at 17:28

To get xml file you expecting for, try this one:

[Serializable]
    public class TestObj
    {
        [XmlElement(ElementName = "question")]
        [XmlElement(typeof(QuestionObj))]
        public List<QuestionObj> Questions { get; set; }

        public int Id { get; set; }
        public string Name;
    }

[Serializable]
    public class QuestionObj
    {
        [XmlElement(ElementName = "stem")]
        public string Stem { get; set; }


        [XmlElement("answers")]
        public List<AnswerObj> Answers { get; set; }

        public int TestId { get; set; }
        public int Id { get; set; }
    }

[Serializable]
   public class AnswerObj
    {
        [XmlElement(ElementName = "answer")]
        public string Answer { get; set; }

       public int Id { get; set; }
       public int StemId { get; set; }
    }

score 0 · Answer 4 · answered Nov 28 '11 at 18:44

0

Sorry, but I need to ask. Are you initializing the AnswerObj properly, and set the answer in it? In a XmlArrayItem you will get another object in it not just a string answer.

answered Nov 28 '11 at 18:44

Franze Caminha

141
7

deserialize xml to list

4 Answers4