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Linq pocket reference ebook





Demonstrating the overwhelming majority of linq operators and protoypes, Joseph Rattz,., and Dennis Hayes condense their extensive experience and expertise into a desk companion that is essential for any serious.NET professional.
Min( / 5; / 6; The quantifiers return a bool value: bool hasTheNumberNine ntains (9 bool hasMoreThanZeroElements y( bool hasAnOddElement y (n n 2 1 / true / true / true Because these operators dont return a collection, you cant call further operators on their.
Where Pro linq: Language Integrated Query in VB 2008 returns your investment is in the hours, and sometimes days, spent by the authors determining why something may not work as expected.
This is because win 8 aio 16 in 1 iso subqueries are called indirectlythrough a delegate in the case of a local query, or through an expression tree in the case of an interpreted query.It then ignores the remaining elements: int numbers 3, 5, 2, 234, 4, 1 ; var takeWhileSmall numbers.This section examines the key features of this technology.Product localProducts Array( var sqlQuery FilterSortProducts (oducts var localQuery FilterSortProducts (Queryable(.Finally, you'll see how to extend linq for custom applications.The file will be sent to selected email address.Created by the authors and free to download, linqpad will not only help you learn linq, it will have you thinking in linq.Linq to SQL automatically populates the foreign keys when you do this: var p1 new Purchase ID100, Description"Bike Price500 ; var p2 new Purchase ID101, Description"Tools Price100 ; Customer cust ngle (c 1 50 linq Pocket Reference d (p1 move (p2 bmitChanges( / Inserts the.ToArray copies the output of a query to an array; ToList copies to a generic List : var numbers new List int ( ) 1, 2 ; List int timesTen numbers.Select (n n * 10).ToList( / Executes immediately into a List int ear( Console.
In this case, var is more than just a clutter reduction device; its a necessity.
With the Where operator, it indicates whether an element should be included in the output 6 linq Pocket Reference sequence.Kimmel begins by reviewing the state-of-the-art C# programming techniques linq uses, including anonymous types, partial methods, and Lambda expressions.In SQL, you reference a table alias in the select clause before defining it in a from clause.The input sequence is enumerated only when the decorator is enumerated.Getting Started 3 In this book, we describe such queries as lambda queries.Query Syntax Versus Lambda Syntax Comprehension and lambda syntax each have advantages.ElementAt (1 / 10 / 6 / 9 Lambda Queries 9 The aggregation operators return a scalar value, usually of numeric type: int count unt( int min numbers.For instance, suppose you wanted to load all customers and their purchases in a single SQL round trip.The lambda expression helps guide and shape the query.The upcoming Building Query Expressions section covers IQueryable in more detail.There is one aspect, however, in which linq to SQL has special deferred execution semantics, and that is when a subquery appears inside a Select expression: With local queries, you get double deferred execution because from a functional perspective, youre selecting a sequence of queries.Anywhere else in the query, it translates to SelectMany.As soon as you try to extend the vocabulary, youre no longer interoperable.WriteLine (me In such cases, the compiler omits the projection when translating to lambda syntax.The only restriction is that each comprehension component must be complete (i.e., start with a from clause and end with a select or group clause).



A better choice for local queries is Join or GroupJoin, described in the following sections.

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