Luke Hoban Senior Program Manager Microsoft Session Code: DTL319

Quick Recap: Querying with LINQ LINQ to Objects: LINQ to SQL: A unified way to write queries for objects and databases! But how does it really work? var query = from c in where c.City == "London" select new { c.ContactName, c.Phone }; var query = from c in where c.City == "London" select new { c.ContactName, c.Phone }; customers db.Customers

LINQ to Objects Name Title Company

LINQ to Objects Query Translation Query Expressions Extension Methods Query Methods var query = from c in customers where c.City == "London" select new { c.ContactName, c.Phone }; var query = customers.Where(c => c.City == "London").Select(c => new { c.ContactName, c.Phone }); Enumerable var query = Enumerable.Select( Enumerable Enumerable.Where(customers, c => c.City == "London"), c => new { c.ContactName, c.Phone } );

LINQ to SQL Name Title Company

LINQ to SQL Query Translation Query Expressions Extension Methods Query Methods var query = from c in db.Customers where c.City == "London" select new { c.ContactName, c.Phone }; var query = db.Customers.Where(c => c.City == "London").Select(c => new { c.ContactName, c.Phone }); Queryable var query = Queryable.Select( Queryable Queryable.Where(db.Customers, c => c.City == "London"), c => new { c.ContactName, c.Phone } );

What We Learned… LINQ to Objects: Code that directly implements your intent LINQ to SQL: Data that represents your intent The difference is all in the extension methods!

Download Lutz Roeder's.NET Reflector: How to build the Expression Tree Visualizer: linq-farm-seed-using-the-expression-tree-visualizer.aspx Explore LINQ Samples on MSDN Code Gallery: LINQ Resources

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