XSD2Code classes require duplicate-named element containing collection of elements

Question

Given XSD like:

  <xs:complexType name="accident">
    <xs:sequence>
      <xs:element name="NAME" type="xs:string" />
      <xs:element name="DESCRIPTION" type="xs:string" />
      <xs:element name="CREATIONDATE" type="xs:dateTime" />
    </xs:sequence>
  </xs:complexType>

  <xs:element name="accidents">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="accident" type="accident" maxOccurs="unbounded" minOccurs="0"/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>

I expect XML like:

<?xml version="1.0" encoding="UTF-8"?>
<accidents>
  <accident>
    <NAME>Accident 123</NAME>
    <DESCRIPTION>Car crash</DESCRIPTION>
    <CREATIONDATE>2016-01-20T12:08:00+00:00</CREATIONDATE>
  </accident>
</accidents>

I used XSD2Code to generate C# classes so I can easy deserialize XML from a web-service. But they weren't working right - they were successfully loading a test XML like my example but there were zero accident elements.

So I decided to reverse the process:

    accidents aa = new accidents();
    accident a = new accident();
    a.NAME = "test";
    aa.accident.Add(a);
    aa.SaveToFile("accidents.xml");

This emitted the following XML:

<?xml version="1.0"?>
<accidents xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <accident>
    <accident>
      <NAME>test</NAME>
      <CREATIONDATE>0001-01-01T00:00:00</CREATIONDATE>
    </accident>
  </accident>
</accidents>

If I attempt to deserialize that XML, it works just fine. But note, there is a nested accident which is not correct and I have no idea it would do this or what to do to fix it!

This seems to be a similar question but since it didn't get much attention and the XSD isn't included, I'm not sure: xsd2code creates extra nested collection when serializing lists

score 1 · Answer 1 · answered Feb 17 '17 at 22:50

I'm a bit late on the scene for this one but here goes anyway !!

I have been using Xsd2Code myself for a while to take advantage of some cool features, but I have found it does have some annoying quirks. I agree that this issue you describe looks like a bug. However I have found that the issue disappears if your collection is itself a child element of another complex type. If you are happy for your "accidents" to exist as a property of a "report" for example, then you would alter your schema as follows:

 <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified">
  <xs:complexType name="accident">
    <xs:sequence>
      <xs:element name="NAME" type="xs:string" />
      <xs:element name="DESCRIPTION" type="xs:string" />
      <xs:element name="CREATIONDATE" type="xs:dateTime" />
    </xs:sequence>
  </xs:complexType>
  <xs:complexType name="accidents">
     <xs:sequence>
       <xs:element name="accident" type="accident" maxOccurs="unbounded" minOccurs="0"/>
     </xs:sequence>
  </xs:complexType>
  <xs:complexType name="report">
    <xs:sequence>
      <xs:element name="accidents" type="accidents"/>
    </xs:sequence>
  </xs:complexType>   
</xs:schema>

When you run this through the Xsd2Code tool you will find that the generated code creates the accidents property of report type as a list of accidents and will serialize in the way you would expect it.

Your test code should look more like this:

        report r = new report();
        r.accidents = new List<accident>();
        accident a = new accident();
        a.NAME = "test";
        r.accidents.Add(a);
        r.SaveToFile("accidents.xml");

The dodgy accidents class is still generated unfortunately - which could cause confusion to other developers, but there is a way to prevent this. First, put the accident and accidents complexType definitions in a file, accidents.xsd. Then put the report definition in report.xsd with an include statement referencing accidents.xsd. Only pass report.xsd through the Xsd2Code tool. The malformed accidents class will not appear in the generated code. This is just an illustrative example of course - expand as required. In the absence of a fix, this has been a very good solution for me - hopefully it will suit your needs.

Eric Hirst · Answer 2 · 2016-06-13T18:24:52.863

You might start by specifying a target namespace and explicit qualification flags in your XSD. That is, convert your xsd to:

<?xml version="1.0" encoding="utf-8"?>
<xs:schema attributeFormDefault="unqualified"
         elementFormDefault="qualified"
         xmlns:xs="http://www.w3.org/2001/XMLSchema"
         targetNamespace="http://example.com/foo"
         xmlns="http://example.com/foo">

<xs:complexType name="accident">
  <xs:sequence>
    <xs:element name="NAME" type="xs:string" />
    <xs:element name="DESCRIPTION" type="xs:string" />
    <xs:element name="CREATIONDATE" type="xs:dateTime" />
  </xs:sequence>
</xs:complexType>

<xs:element name="accidents">
  <xs:complexType>
    <xs:sequence>
      <xs:element name="accident" type="accident" maxOccurs="unbounded" minOccurs="0"/>
    </xs:sequence>
  </xs:complexType>
</xs:element>

</xs:schema>

and your XML to:

<?xml version="1.0" encoding="UTF-8"?>
<accidents xmlns="http://example.com/foo"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xsi:schemaLocation="http://example.com/foo foo.xsd">
  <accident>
    <NAME>Accident 123</NAME>
    <DESCRIPTION>Car crash</DESCRIPTION>
    <CREATIONDATE>2016-01-20T12:08:00+00:00</CREATIONDATE>
  </accident>
</accidents>

(You will need to save your xsd file as foo.exe for the above reference to work).

I'm not sure if this will fix your XSD2Code issue, but I've used this header format with xsd.exe for lots of equivalent (and much more complex) code. It gets you Intellisense in your XML and might also be sufficient to get XSD2Code to behave properly.

I tested these sort of things and they don't help. I'm looking at using Xsd.exe instead of Xsd2Code but that seems a cheat - and it doesn't auto-create save/load & [de]serialize code :( — Mr. Boy, Jun 10 '16 at 09:59
Ah, too bad. If you decide to swallow your pride and go with xsd.exe, you can create a templatized static XmlSerializationHelper class with public Serialize and Deserialize methods that you can call from anywhere. — Eric Hirst, Jun 13 '16 at 17:44
It seems a pretty major bug in Xsd2Code so I'm assuming it is user-error... otherwise they wouldn't have bothered making it when Xsd.exe is already available :) — Mr. Boy, Jun 13 '16 at 19:23
I'm basically doing what you suggest as an interim solution anyway, as per http://stackoverflow.com/questions/37747126/share-deserialization-code-between-generated-classes-generics-or-inheritance-i — Mr. Boy, Jun 13 '16 at 19:24

XSD2Code classes require duplicate-named element containing collection of elements

2 Answers2