how can i get the last element of a query?

once I query from the DomainModelEntityManager, I get a set of data, how can i get the first and last element of that set of data?

but some time I don't have 'ToList()' method, how can I make it appear? it only has 'ToHashSet()' and others, no 'ToList()'!

i think this is advanced knowledge. thanks for replying

Originally posted by monkeyking no, I don't think that's soluction, even I include System.Collections.Generic, it still doesn't have 'ToList()' method.

You need to reference the System.Core assembly in your project, and add using statements for System.Linq and System.Collections.Generic to your code file.

ToList() is required by the IEnumerable<T> interface (which is defined in System.Collections.Generic); therefore, any type that implements IEnumerable<T> will have an implementation of ToList().  This is true of our EntityQuery<T>. However, as you apply extension methods to a query, most such methods return a new query (using the prior one as input), and sometimes the return type can change.  But anything that's an IEnumerable<T> (this includes EntityQuery<T>, IEntityQuery<T>, and IQueryable<T>) should provide ToList().

Note that under certain circumstances you can get the non-generic IEnumerable instead of IEnumerable<T>. In those cases you may be able to call the Cast() method on the IEnumerable to cast it to an IEnumerable<T>, which will have ToList().