LINQ to DataSet with strongly typed data after migration from .NET 3.5 to 4.0

I'm in the progress of migrating our projects from .NET 3.5 to .NET 4.0. Previously I used to be able to use statements on typed datasets such as:

dr = myDataSet.SomeTable.FirstOrDefault(Function(x) x.IdSome = targetId)

This however no longer works. I've already tried adding the reference to System.Data.DataSetExtensions and modify the code to use .AsEnumerable() - however, this only yields a DataRow, not a SomeRow (as would be contained within the SomeTable)

dr = myDataSet.SomeTable.AsEnumerable().FirstOrDefault(Function(x) x.IdSome = targetId)

The resulting error is 'IdSome' is not a member of 'System.Data.DataRow' - some other statements fail with an Overload resolution failed due to the same reason.

How can I retain the type safe, non-magic string code in .NET 4.0?

Solution

Turns out that the datasets were messed up during the conversion. After regenerating them (opening one in designer, "Run Custom Tool" on all datasets) fixed the inheritance.