asp.net - How can I use Telerik RadGrid's filter expression to filter a custom List data object?

Question

I am using Telerik RadGrid with LINQExpressions enabled.

I am binding this grid to data that I retrieve from Cache in NeedDataSource event as in code below.

The problem is, when I step through my code after inputting a filter, then I get this as filter expression - "(iif(MemberName == null, \"\", MemberName).ToString().StartsWith(\"T\"))". How would I use this with my listFromCache object? Perhaps, some LINQ trick? MemberName is a property of Document object. It seems its impossible to use the FilterExpression that I get in code-behind from RadGrid's object model.

I am using C#.

 List<Document> listFromCache = Cache[dataCacheName] as List<Document>;

 if (listFromCache != null)
 {

   //FILTER listFromCache here

 }