Maybe you are referring to a CompositeFilterDescriptor and not the view model which is for internal use only. Even if you were able to convert a string to a view model -- you can't do anything with it after that. This is one of our internal parts. It is public because Silverlight wants it to be, but you can treat it as an internal class.
The real information holder here is the CompositeFilterDescriptor class which is public and you can use it for anything. It simply holds filtering criteria/information -- i.e. other CompositeFilterDescriptors or simple (leaf) FilterDescriptors. It is a kind of a property bag of sort.
Anyway, I am afraid that converting to a string is a one-way process only. I have written it to help me when I am debugging, that's all. It does not follow any special format or something. It is for debugging purposes only.
Of course, you can implement your custom parser that would parse such a string and then use the public API to re-construct the filter descriptor.
In fact your task is to take a .NET object, serialize it to something and then deserialize it back. This can be done in many different ways in Silverlight and is beyond the scope of Telerik support.
I hope this helps.
the Telerik team
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