book

LINQ For Dummies®

Name: LINQ For Dummies®
Author: John Paul Mueller
ISBN: 9780470277942

by John Paul Mueller

August 2008

Beginner to intermediate

364 pages

8h 35m

English

For Dummies

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Copyright
About the Author
Author's Acknowledgments
Introduction
About This BookConventions Used in This BookWhat You Should ReadWhat You Don't Have to ReadFoolish AssumptionsHow This Book Is OrganizedPart I: An Overview of LINQPart II: Using Standard LINQ to TechnologiesPart III: Extending LINQ to New HorizonsPart IV: The Part of TensThe accompanying Web siteIcons Used in This BookWhere to Go from Here
I. An Overview of LINQ
1. Getting to Know LINQ
1.1. Considering LINQ1.1.1. Understanding the task that LINQ performs1.1.2. Contemplating why you need LINQ1.1.3. Defining the LINQ design goals1.1.4. Understanding the LINQ requirements1.2. Using LINQ in the Real World1.3. Understanding Declarative Programming1.4. An Overview of the LINQ Namespaces1.4.1. System.Linq namespace1.4.2. System.Linq.Expressions namespace1.4.3. System.Data.Linq namespace1.4.4. System.Data.Linq.Mapping namespace1.4.5. System.Data.SqlClient namespace1.4.6. System.Data.SqlClient.Implementation namespace1.4.7. System.Xml.Linq namespace
2. Creating Simple LINQ Queries
2.1. Defining the LINQ Keywords2.1.1. Working with from2.1.2. Working with where2.1.3. Working with orderby2.1.4. Working with join2.1.5. Working with let2.2. Creating a Simple from Query2.2.1. Understanding the simple query application code2.2.2. Using the debugger to see the simple query in action2.3. Filtering a Query2.4. Grouping Queries2.5. Creating Queries from Multiple Sources2.5.1. Understanding the multiple-source application code2.5.2. Working with the alternative multiple-source example2.5.3. Using calculated values in multiple-source queries2.6. Working with the Standard Query Operators2.7. Mapping Keywords to Methods
3. Considering the .NET Language Extensions
3.1. An Overview of the Language Extensions3.2. Working with Lambda Expressions3.3. Understanding the Role of the IEnumerable and IEnumerable <T> Interfaces3.4. Understanding Object Initializers3.5. Understanding Collection Initializers3.6. Working with Extension Methods3.7. Working with Partial Methods3.8. An Overview of Expression Trees3.9. Working with Query Expressions
4. Working with LINQ in Visual Basic .NET
4.1. Understanding the Visual Basic Differences4.2. Creating the Simple Visual Basic Example4.2.1. Working with From4.2.1.1. Understanding the code4.2.1.2. Using the debugger to see the code execute4.2.2. Working with Where4.2.3. Working with Order By4.2.4. Working with Join4.2.5. Working with Let4.3. Using the Additional Visual Basic Keywords4.3.1. Working with Aggregate4.3.2. Working with Distinct4.3.3. Working with Skip4.3.4. Working with Take4.4. Working with Lambda Functions in Visual Basic

5. Working with LINQ in Visual Studio 2005
5.1. Obtaining LINQ Support for Visual Studio 20055.2. Installing LINQ Support5.3. Creating the Simple Visual Studio 2005 Project5.3.1. Defining the project5.3.2. Working with from5.3.2.1. Understanding the code5.3.2.2. Using the debugger5.3.3. Working with join5.3.4. Working with where5.3.5. Working with orderby5.3.6. Working with let
II. Using Standard LINQ to Technologies
6. LINQ to Object
6.1. Considering the Use of Objects with LINQ6.2. Creating the Simple Object Query Example6.3. Understanding the Role of Deferred Operators6.4. Creating the Deferred Operator Examples6.4.1. Working with Concat6.4.2. Working with AsEnumerable, AsQueryable, Cast, and OfType6.4.3. Working with OfType and Where6.4.4. Working with DefaultIfEmpty, Empty, Range, and Repeat6.4.5. Working with GroupBy and ToLookup6.4.6. Working with GroupJoin and Join6.4.7. Working with Skip, SkipWhile, Take, and TakeWhile6.4.8. Working with Select and SelectMany6.4.9. Working with Distinct, Except, Intersect, and Union6.4.10. Working with OrderBy, OrderByDescending, Reverse, ThenBy, and ThenByDescending6.5. Understanding the Role of Nondeferred Operators6.6. Creating the Nondeferred Operator Examples6.6.1. Working with Aggregate, Average, Count, LongCount, Max, Min, and Sum6.6.2. Working with ToArray, ToDictionary, ToList, and ToLookup6.6.3. Working with ElementAt, ElementAtOr Default, First, FirstOrDefault, Last, LastOrDefault, Single, and SingleOrDefault6.6.4. Working with SequenceEqual6.6.5. Working with All, Any, and Contains
7. LINQ to DataSet
7.1. Considering the Use of DataSets with LINQ7.2. Creating the Simple DataSet Example7.2.1. Defining the test tables7.2.2. Outputting the results7.2.3. Exploring the connection7.3. Understanding the LINQ to DataSet Operators7.4. Creating the Filtered Output Example7.4.1. Creating a simple display7.4.2. Modifying the filtered output7.4.3. Using the CopyToDataTable operator7.4.4. Working with typed DataSets7.4.4.1. Defining the DataSet7.4.4.2. Working with the typed DataSet7.5. Working with Multiple DataSet Tables
8. LINQ to SQL Server
8.1. Considering the Use of SQL Server with LINQ8.2. Obtaining and Installing the Northwind Database8.2.1. Downloading the database8.2.2. Installing the database8.2.3. Testing the Visual Studio connection8.2.4. Generating the Northwind entity classes and XML mapping files8.3. Creating the Simple SQL Server Query Example8.3.1. Overcoming the Visual Studio 2008 connectivity issues8.3.2. Defining the project8.3.3. Adding the code8.3.4. Viewing the debugger output8.4. Using Object Relational Designer8.5. Understanding the LINQ to SQL Server Operators
9. LINQ to XML
9.1. Considering the Use of XML with LINQ9.2. Working with the LINQ to XML API9.3. Understanding the LINQ to XML Operators9.3.1. Working with XDeclaration, XElement, and XDocument9.3.2. Working with XNamespace9.3.3. Working with XProcessingInstruction9.3.4. Working with XAttribute9.3.5. Working with XComment and XText9.3.6. Working with XCData9.3.7. Working with XDocumentType9.3.8. Working with XNodeDocumentOrderComparer9.3.9. Working with XNodeEqualityComparer9.3.10. Working with Remove9.3.11. Working with XName9.4. Creating the Simple XML File Example9.4.1. Creating the project9.4.2. Building an XML document9.4.3. Saving an XML document9.4.4. Loading an XML document
III. Extending LINQ to New Horizons
10. Using LINQ with Office 2007
10.1. Understanding the Office Document Structure10.2. Understanding LINQ Interaction with Office10.3. Obtaining the Required Library10.4. Creating the Office 2007 Document Example10.4.1. Creating the project10.4.2. Understanding the custom properties10.4.3. Reading document properties10.4.4. Writing document properties
11. Advanced LINQ to SQL Server
11.1. Considering SQL Server Issues11.1.1. Understanding concurrency problems11.1.1.1. Understanding the problem and its resolution11.1.1.2. Seeing concurrency checks and resolution in action11.1.1.3. Defining alternatives to ResolveAll()11.1.1.4. Using entity class attributes to modify concurrency detection11.1.2. Overcoming performance issues11.1.2.1. Using Column attributes11.1.2.2. Relying on standard database performance tricks11.1.2.3. Performing database updates only as needed11.1.2.4. Using eager loading11.2. Creating the Database Modification Example11.2.1. Performing an insert11.2.2. Performing an update11.2.3. Performing a delete11.3. Using Concurrency Checks and Resolving Errors11.3.1. Resolving conflicts at the object level11.3.2. Resolving conflicts at the member level
12. LINQ to Active Directory
12.1. Working with Specific Active Directory Objects12.2. Defining Active Directory Variables12.3. Obtaining the LINQ to Active Directory Provider12.4. Creating the Simple Active Directory Query Example12.4.1. Performing the project setup12.4.2. Defining an Active Directory object class12.4.3. Creating a root node pointer12.4.4. Reading user information12.4.5. Writing user information12.5. Understanding the Limitations of Active Directory Interaction12.5.1. Some LINQ methods aren't implemented12.5.2. Defining the need for LDAP patience
13. Other LINQ to Strategies
13.1. Understanding the Qualifications for a LINQ to Solution13.2. Accessing COM+ Using LINQ13.2.1. COM+ accessed as a Web service13.2.2. COM+ accessed using interop functionality13.3. Creating the Resource Description Format (RDF) Files Example13.3.1. A quick overview of RDF13.3.2. A quick overview of SPARQL13.3.3. Starting the project13.3.4. Configuring the project13.3.4.1. Defining the client project13.3.4.2. Defining the host project13.3.5. Creating the host application13.3.6. Creating the application class definition13.3.7. Reading RDF files13.4. Creating the MySQL Example13.4.1. Getting the MySQL ADO.NET connector13.4.2. Compiling the DbLinq.DLL and DbLinq.MySQL.DLL files13.4.3. Configuring the database13.4.4. Defining the MySQL project13.4.5. Developing the query code
IV. The Part of Tens
14. Ten Ways to Improve LINQ Development
14.1. Using LINQ Tools to Simplify Coding14.1.1. Getting the VLinq add-in application14.1.2. Creating a VLinq query14.1.3. Using a VLinq query in an application14.2. Using LINQ to Create Self Documenting Code14.3. Analyzing Code Patterns14.4. Querying a Code Snippet Database14.5. Locating Other Development Resources14.6. Using LINQ to Query Data Formats14.7. Finding Usage Trends14.8. Developing a LINQ Library14.9. Sharing LINQ Queries with Others14.10. Analyzing Compiler and IDE Output
15. Ten Ways to Reduce Application Support Costs
15.1. Creating Self-Modifying Queries15.2. Using LINQ to Create Reports15.3. Addressing User Search Needs15.4. Creating User-Friendly Mashups15.5. Making Help More Accessible15.6. Organizing and Querying Support Requests and Responses15.7. Developing Fast Searches from Multiple Sources15.8. Helping Users Locate Existing Resources15.9. Performing Support Task Automation15.10. Improving Application and System Management
16. Ten LINQ Resources
16.1. Starting with the Microsoft Developer Network16.2. Getting Tips from the Microsoft Blogs16.3. Finding Help in Third-Party Web Sites16.4. Finding Help in Third-Party Newsletters and Blogs16.5. Using Other Sources for LINQ to Objects Projects16.6. Using Other Sources for LINQ to SQL Server Projects16.7. Using Other Sources for LINQ to XML Projects16.8. Considering Other LINQ to Sources Projects16.9. Getting Help with Visual Basic Projects16.10. Getting Help with C# Projects

Content preview from LINQ For Dummies®

Chapter 3. Considering the .NET Language Extensions

In this chapter

Understanding the language extensions
Using lambda expressions
Working with the IEnumerable and IEnumerable<T> interfaces
Considering object initializers
Considering collection initializers
Using extension methods
Using partial methods
Understanding expression trees
Defining query extensions

LINQ doesn't appear as part of older versions of Visual Studio. Yes, you can use LINQ in these older versions, but you must use special techniques to do it — not much is automatic (see Chapter 5 for details). Part of the reason that LINQ works the way it does is the addition of language extensions to .NET Framework. The language extensions make it possible for .NET Framework to support LINQ and for you to create queries of various types.

This chapter provides an overview of the major .NET language extensions from the C# developer's perspective. Chapter 4 provides information about the differences between C# and Visual Basic .NET from the Visual Basic .NET developer's perspective. Although the two languages do support the same basic features, you'll find that Visual Basic .NET provides some additional automation that C# doesn't and C# provides flexibility that Visual Basic .NET doesn't. Either language will perform all basic queries and most complex queries without any problem.

The chapter begins with an overview of the extensions in .NET Framework 3.5. The sections that follow provide additional details on each of these extensions. In many ...

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LINQ For Dummies®

by John Paul Mueller

Chapter 3. Considering the .NET Language Extensions

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