Writing Lambda Query Expressions in VB.Net using linq to sql provider

I'm just not understanding on how to create a lambda expression instead of using a regular comprehension linq queries. All of the examples i see are not query a database using linq to sql. i want to able to construct a lambda expression that get my the orders from the northwind database where the country equals "us". I know how to construct this using the standard linq query, but just not using lambdas 开发者_运维问答in vb.net.

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Not sure of the exact northwind structure but something like this probably:

Dim dc as new NorthwindDataConext()
Dim usOrders as List(of Order) = dc.Orders.Where(Function(o) o.Country = "US").ToList();