Linq Pocket Reference (Pocket Reference (O'Reilly))

174 Pages·2008·1.16 MB·English

by  Joseph Albahari

LINQ
Pocket Reference

LINQ
Pocket Reference
Joseph Albahari and Ben Albahari
Beijing • Cambridge • Farnham • Köln • Paris • Sebastopol • Taipei • Tokyo
LINQ Pocket Reference
by Joseph Albahari and Ben Albahari
Copyright © 2008 Joseph Albahari and Ben Albahari. All rights reserved.
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Printing History:
February 2008: First Edition.
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ISBN: 978-0-596-51924-7
[TM]
Contents
Getting Started 1
Lambda Queries 4
Chaining Query Operators 4
Composing Lambda Expressions 6
Natural Ordering 9
Other Operators 9
Comprehension Queries 10
Iteration Variables 12
Query Syntax Versus SQL Syntax 13
Query Syntax Versus Lambda Syntax 13
Mixed Syntax Queries 14
Deferred Execution 15
Reevaluation 16
Outer Variables 17
How Deferred Execution Works 17
Chaining Decorators 19
How Queries Are Executed 20
Subqueries 22
Subqueries and Deferred Execution 25
v
Composition Strategies 25
Progressive Query Building 25
The into Keyword 27
Wrapping Queries 28
Projection Strategies 30
Object Initializers 30
Anonymous Types 30
The let Keyword 32
Interpreted Queries 33
How Interpreted Queries Work 35
AsEnumerable 38
LINQ to SQL 40
LINQ to SQL Entity Classes 40
DataContext 42
Automatic Entity Generation 45
Associations 45
Deferred Execution with LINQ to SQL 47
DataLoadOptions 48
Updates 50
Building Query Expressions 52
Delegates Versus Expression Trees 53
Expression Trees 55
Query Operator Overview 59
Filtering 62
Where 63
Take and Skip 65
TakeWhile and SkipWhile 65
Distinct 66
vi | Contents
Projecting 66
Select 67
SelectMany 72
Joining 82
Join and GroupJoin 83
Ordering 92
OrderBy, OrderByDescending, ThenBy, ThenByDescending 92
Grouping 95
GroupBy 96
Set Operators 100
Concat and Union 100
Intersect and Except 100
Conversion Methods 101
OfType and Cast 101
ToArray, ToList, ToDictionary, ToLookup 103
AsEnumerable and AsQueryable 104
Element Operators 104
First, Last, Single 105
ElementAt 106
DefaultIfEmpty 107
Aggregation Methods 107
Count and LongCount 107
Min and Max 108
Sum and Average 109
Aggregate 110
Quantifiers 111
Contains and Any 111
All and SequenceEqual 112
Contents | vii
Generation Methods 112
Empty 112
Range and Repeat 113
LINQ to XML 113
Architectural Overview 114
X-DOM Overview 115
Loading and Parsing 117
Saving and Serializing 118
Instantiating an X-DOM 118
Functional Construction 119
Specifying Content 120
Automatic Deep Cloning 121
Navigating/Querying an X-DOM 122
Child Node Navigation 122
Parent Navigation 126
Peer Node Navigation 127
Attribute Navigation 128
Updating an X-DOM 128
Simple Value Updates 128
Updating Child Nodes and Attributes 129
Updating Through the Parent 130
Working with Values 133
Setting Values 133
Getting Values 133
Values and Mixed Content Nodes 135
Automatic XText Concatenation 136
viii | Contents