Filling a DataSet or DataTable from a LINQ query result set

Question

How do you expose a LINQ query as an ASMX web service? Usually, from the business tier, I can return a typed DataSet or DataTable which can be seri

Answer 1

To perform this query against a DataContext class, you'll need to do the following:

MyDataContext db = new MyDataContext();
IEnumerable<DataRow> query = 
    (from order in db.Orders.AsEnumerable()
        select new
        {
            order.Property,
            order.Property2
        })
    as IEnumerable<DataRow>;
return query.CopyToDataTable<DataRow>();

Without the as IEnumerable<DataRow>; you will see the following compilation error:

Cannot implicitly convert type 'System.Collections.Generic.IEnumerable' to 'System.Collections.Generic.IEnumerable'. An explicit conversion exists (are you missing a cast?)