Webservice serialization problem

Hi,

I'm having a problem with calling a webservice on the compact framework. The
compact framework appears to have a problem with serializing inherited
types. Let me give you an example (for those familiar with it, I'm
connecting to the MS CRM webservices).

There's a base class ColumnSetBase with two subclasses, AllColumns and
ColumnSet. There a webservice method that takes as a parameter a class with
a property of type ColumnSetBase.

When I fill that property with an object of type ColumnSet and I look at
what the webservice receives, the ColumnSet is empty.

Another example. Base class QueryBase, two subclasses QueryExpression and
QueryByAttribute. When I put an object of type QueryExpression in a property
of type QueryBase and pass that to the webservice, it's empty. However, I
wrote a test method in the webservice that takes a parameter of type
QueryExpression. When I pass in an object of type QueryExpression it works.
So it seems to go wrong with the casting from sub to base class.

I generated the webreferences in a separate device project. And when I
reference that project in a .NET windows application, everything works fine.

I have some workarounds, like xmlserializing the object to a string and then
passing it to an adapted version of the webservice method. If I do that, the
properties are serialized fine. But I'd rather find out why this doesn't
work.

Any ideas? I couldn't find anything on the web related to this problem.

Thanks,

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Jeffry van de Vuurst
CWR Mobility
www.cwrmobility.com
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