R – XmlSerialization of collections

netxml-serialization

I want to serialize the following Xml structure:

  <XmlRootElement>
     <Company name="Acme Widgets LLC">
        <DbApplication name="ApplicationA" vendor="oracle">
           <ConnSpec environment="DEV" 
                     server="DBOraDev1201" 
                     database="AppA" 
                     userId="MyUser" 
                     password="5613456#6%^%$%$#" />
           <ConnSpec environment="QA" 
                     server="DBOraQA1205" 
                     database="AppA" 
                     userId="MyUser" 
                     password="5613456#6%^%$%$#" />
       </DbApplication>
       <DbApplication name="AnotherApp" "vendor="SQLServer">
           <ConnSpec environment="DEV" 
                     server="DBMsSqlDev1201" 
                     catalog="AnoptherApp" 
                     userId="MyUser" 
                     password="5613456#6%^%$%$#" />
           <ConnSpec environment="QA" 
                     server="DBMsSqlQA1565" 
                     catalog="AnotherApp" 
                     userId="MyUser" 
                     password="5613456#6%^%$%$#" />
       </DbApplication>
     </Company>
     <Company name = "ExpertSoftware Inc" ....
        ...
     </Company>
  </XmlRootElement>

but I have discovered in link text

Quote from above link:
…

  • Q: Why aren't all properties of
    collection classes serialized?
  • A: The XmlSerializer only serializes
    the elements in the collection when
    it detects either the IEnumerable or
    the ICollection interface. This
    behavior is by design. The only work
    around is to re-factor the custom
    collection into two classes, one of
    which exposes the properties
    including one of the pure collection
    types.

…

after discovering that you can't serialize or deserialize a collection that has other Xml attributes in it… The suggested workaround is to separate the element that has the collection from the the ones that have other attributes… i.e, You have to change the structure so that it looks like this instead:

  <XmlRootElement>
     <Companys>
        <Company name="Acme Widgets LLC">
           <DbApplications>
               <DbApplication name="ApplicationA" vendor="oracle">
                  <ConnSpecs>
                     <ConnSpec environment="DEV" 
                         server="DBOraDev1201" ...  />
                     <ConnSpec environment="QA" 
                         server="DBOraQA1205" 
                         database="AppA" ... />
                  </ConnSpecs>
               </DbApplication>
               <DbApplication name="AnotherApp" "vendor="SQLServer">
                  <ConnSpecs>
                      <ConnSpec environment="DEV" ... />
                      <ConnSpec environment="QA"  ... />
                  </ConnSpecs>
                </DbApplication>
           </DbApplications>
         </Company>
         <Company name = "ExpertSoftware Inc" ....
             ...
         </Company>
     </Companys>
  </XmlRootElement>

Does anyone know why this is so? or if there is some other way to do this?

Best Answer

If you are using XmlSerializer you need to indicate it how to serialize your collections:

public class XmlRootElement
{
    [XmlElement(ElementName="Company")]
    public Company[] Company { get; set; }

    // Other properties ....
}

public class Company
{
    [XmlAttribute(AttributeName="name")]
    public string Name { get; set; }

    [XmlElement(ElementName = "DbApplication")]
    public DbApplication[] DbApplication { get; set; }

    // Other properties ....
}

public class DbApplication
{
    [XmlElement(ElementName = "ConnSpec")]
    public ConnSpec[] ConnSpec { get; set; }

    // Other properties ....
}

public class ConnSpec
{
    // Other properties ....
}

And then:

using (Stream stream = new FileStream("test.xml", FileMode.Open, FileAccess.Read, FileShare.Read))
{
    XmlSerializer serializer = new XmlSerializer(typeof(XmlRootElement));
    XmlRootElement root = (XmlRootElement)serializer.Deserialize(stream);
}

Hope this helps.

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