problem with SQL CE and orderby linq clause

I am using linq with SQL CE, but for a simple query like this:

var points=from i in this.DomainBoundaryPoints orderby i.Index select i;

I get this error:

Could not find an implementatio开发者_StackOverflown of the query pattern for source type 'System.Data.Linq.EntitySet<DAL.DomainBoundaryPoint>'.  'OrderBy' not found.  Are you missing a reference to 'System.Core.dll' or a using directive for 'System.Linq'?

Does SQL CE support 'order by' TSQL clause? Where is the problem?

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Of course SQL CE supports orderby...

Try to do what the error message tells you...

• add a reference to System.Core if it's not there
• add a using directive for System.Linq