C# XML list deserialization; no exception thrown, but no objects deserialized

Question

I'm trying to deserialize XML into C# objects. When I run my code, no exceptions are thrown, but my resulting object is empty. I'm kind of out of ideas for debugging.

My serialization domain classes:

[SerializableAttribute()]
[XmlTypeAttribute(TypeName = "group_lookup_result")]
[XmlRootAttribute("group_lookup_result")]
public class GroupLookupResult
{
    private string _groupId;
    private string _groupName;

    public GroupLookupResult()
    {
        _groupId = "";
        _groupName = "";
    }

    [XmlElement("group_id")]
    public string GroupID
    {
        get { return _groupId; }
        set { _groupId = value; }
    }

    [XmlElement("group_name")]
    public string GroupName
    { 
        get { return _groupName; }
        set { _groupName = value; }
    }
}

[SerializableAttribute()]
[XmlRootAttribute(ElementName = "group_lookup_result_list", IsNullable = false, Namespace = "http://ws.byu.edu/namespaces/gro/v1")]
[XmlTypeAttribute(TypeName = "group_lookup_result_list", Namespace = "http://ws.byu.edu/namespaces/gro/v1")]
public class GroupLookupResultList
{
    private List<GroupLookupResult> _searchResults;

    public GroupLookupResultList() { }

    [XmlArrayItem(IsNullable = false)]
    public List<GroupLookupResult> group_lookup_results
    {
        get { return _searchResults; }
        set { _searchResults = value; }
    }

}

My deserialization code:

class Program
{
    static void Main(string[] args)
    {
        string incomingXml = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\" ?>" +
            "<ns2:group_lookup_result_list xmlns:ns2=\"http://ws.byu.edu/namespaces/gro/v1\">" + 
                "<group_lookup_results>" + 
                    "<group_lookup_result>" + 
                        "<group_id>bradtest</group_id>" + 
                        "<group_name>Brad's Test Group</group_name>" +
                        "<effective_date>2011-05-04T00:00:00-06:00</effective_date>" + 
                        "<expiration_date>2014-01-10T23:59:59-07:00</expiration_date>" + 
                    "</group_lookup_result>" + 
                    "<group_lookup_result>" + 
                        "<group_id>brjtest</group_id>" + 
                        "<group_name>Bernt's Test Group</group_name>" + 
                        "<effective_date>2011-05-05T00:00:00-06:00</effective_date>" + 
                        "<expiration_date>2012-05-05T23:59:59-06:00</expiration_date>" + 
                    "</group_lookup_result>" + 
                "</group_lookup_results>" + 
            "</ns2:group_lookup_result_list>";
        XmlSerializer searchResultSerializer = new XmlSerializer(typeof(GroupLookupResultList));
        System.IO.StringReader reader = new System.IO.StringReader(incomingXml);

        GroupLookupResultList resultList = (GroupLookupResultList)searchResultSerializer.Deserialize(reader);
        System.Diagnostics.Debug.WriteLine("Deserialized " + resultList.group_lookup_results.Count + " results");
    }
}

I realize that my domain objects don't deserialize the <effective_date> or <expiration_date>, but I've ignored XML elements before and didn't have a problem. I've also tried deserializing a single group_lookup_result and it was successful; it seems that it's just the group_lookup_result_list object (or possibly its List element) that is causing problems. My guess is that I'm not handling the namespaces correctly.

So, my questions are:

What is wrong with my serialization configuration?

or

How can I debug this?

score 1 · Accepted Answer · answered Mar 22 '12 at 19:17

I've managed to replicate this (good example btw) and get the objects deserialized. I added the Form = System.Xml.Schema.XmlSchemaForm.Unqualified to the element declarations and that did the trick. I also adjusted the group_lookup_results property a bit to inform the deserializer about the individual item element names (using XmlArrayItemAttribute).

Code below.

[TestClass]
public class UnitTest1
{
    [TestMethod]
    public void TestMethod1()
    {
        string incomingXml = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\" ?>" +
       "<ns2:group_lookup_result_list xmlns:ns2=\"http://ws.byu.edu/namespaces/gro/v1\">" +
           "<group_lookup_results>" +
               "<group_lookup_result>" +
                   "<group_id>bradtest</group_id>" +
                   "<group_name>Brad's Test Group</group_name>" +
                   "<effective_date>2011-05-04T00:00:00-06:00</effective_date>" +
                   "<expiration_date>2014-01-10T23:59:59-07:00</expiration_date>" +
               "</group_lookup_result>" +
               "<group_lookup_result>" +
                   "<group_id>brjtest</group_id>" +
                   "<group_name>Bernt's Test Group</group_name>" +
                   "<effective_date>2011-05-05T00:00:00-06:00</effective_date>" +
                   "<expiration_date>2012-05-05T23:59:59-06:00</expiration_date>" +
               "</group_lookup_result>" +
           "</group_lookup_results>" +
       "</ns2:group_lookup_result_list>";
        XmlSerializer searchResultSerializer = new XmlSerializer(typeof(GroupLookupResultList));
        System.IO.StringReader reader = new System.IO.StringReader(incomingXml);

        GroupLookupResultList resultList = (GroupLookupResultList)searchResultSerializer.Deserialize(reader);
        System.Diagnostics.Debug.WriteLine("Deserialized " + resultList.group_lookup_results.Count + " results");

    }
}

[SerializableAttribute()]
[XmlTypeAttribute(TypeName = "group_lookup_result")]
[XmlRootAttribute("group_lookup_result")]
public class GroupLookupResult
{
    private string _groupId;
    private string _groupName;

    public GroupLookupResult()
    {
        _groupId = "";
        _groupName = "";
    }

    [XmlElement("group_id", Form = System.Xml.Schema.XmlSchemaForm.Unqualified)]
    public string GroupID
    {
        get { return _groupId; }
        set { _groupId = value; }
    }

    [XmlElement("group_name", Form = System.Xml.Schema.XmlSchemaForm.Unqualified)]
    public string GroupName
    {
        get { return _groupName; }
        set { _groupName = value; }
    }
}

[SerializableAttribute()]
[XmlRootAttribute(ElementName = "group_lookup_result_list", IsNullable = false, Namespace = "http://ws.byu.edu/namespaces/gro/v1")]
[XmlTypeAttribute(TypeName = "group_lookup_result_list", Namespace = "http://ws.byu.edu/namespaces/gro/v1")]
public class GroupLookupResultList
{
    private List<GroupLookupResult> _searchResults;

    public GroupLookupResultList() { }

    [System.Xml.Serialization.XmlArrayAttribute(Form = System.Xml.Schema.XmlSchemaForm.Unqualified)]
    [System.Xml.Serialization.XmlArrayItemAttribute("group_lookup_result", Form = System.Xml.Schema.XmlSchemaForm.Unqualified, IsNullable = false)]
    public List<GroupLookupResult> group_lookup_results
    {
        get { return _searchResults; }
        set { _searchResults = value; }
    }

}

It worked; thanks. I haven't learned about the Form parameters yet. I think that'll be my next reading subject. — RustyTheBoyRobot, Mar 22 '12 at 19:35
@RustyTheBoyRobot yeah, the Form stuff stung me a bit when I first started doing this. I didn't look into the whys after I had found the solution but probably should in retrospect. Another thing that stung often was the not decorating the the list properties properly by making sure had a name for individual elements etc good luck with your solutions — dreza, Mar 22 '12 at 19:48

score 0 · Answer 2 · answered Mar 22 '12 at 19:09

I think you need to specify that its an XmlArray as well:

[XmlArray("group_lookup_results")]
[XmlArrayItem(IsNullable = false)]
public List<GroupLookupResult> group_lookup_results;

There is a more specific example of XmlArray and XmlArrayItem with namespace specifications here

C# XML list deserialization; no exception thrown, but no objects deserialized

What is wrong with my serialization configuration?

How can I debug this?

2 Answers2