Apress pro LINQ Language Integrated Query in C# 2008 phần 4 ppt

... understanding of LINQ to Objects and just what LINQ can do for you, it’s time to learn about using LINQ to query and generate XML. This functionality is called LINQ to XML and, not so coincidentally, ... source input sequence is null. Examples For an example of the first prototype, I begin with a value that I know is not in my input sequence, as shown in Listing 5 -43 Listing...

Ngày tải lên: 06/08/2014, 08:22

... October 23, 2007 4: 37 PM 252 CHAPTER 7 ■ THE LINQ TO XML API XProcessingInstruction.Target on XProcessingInstruction Objects and XProcessingInstruction.Data on XProcessingInstruction Objects To ... value of a processing instruction, simply modify the Target and Data properties of the XProcessingInstruction object. Listing 7-72 is an example. Listing 7-72. Updating a Processing Instruct...

Ngày tải lên: 06/08/2014, 08:22

... don’t you think? I just joined three XML documents in a single query. Surely you now see the power of LINQ to XML. Are you starting to see why LINQ to XML is my favorite part of LINQ? Now how ... make it interesting, I will query on the type attribute, and I will try this one in query expression syntax, as shown in Listing 9-3. Listing 9-3. Obtaining Restricted Elements Wi...

Ngày tải lên: 06/08/2014, 08:22

... do? The LINQ to DataSet operators allow a developer to perform LINQ queries on a DataSet, and since a DataSet can be obtained using normal ADO.NET SQL queries, LINQ to DataSet allows LINQ queries ... query on data in a database using ADO.NET to obtain a DataSet, then turn right around and query that data again using LINQ to DataSet, all within several lines of code. In re...

Ngày tải lên: 06/08/2014, 08:22

... to the query for the respective column. Listing 14- 16 contains an example programmati- cally building a query for such an interface. Listing 14- 16. Programmatically Building a Query Northwind db ... Page 47 4 Tuesday, October 16, 2007 1 :40 PM 45 2 CHAPTER 14 ■ LINQ TO SQL DATABASE OPERATIONS ■Note In the Visual Studio 2008 Beta 2 release and earlier, the InsertOnSubmit meth...

Ngày tải lên: 06/08/2014, 08:22

... Service-Oriented Architecture, 3e Beginning ASP.NET 3.5 Data Access, 2e Beginning C# 2008 Databases Beginning C# 2008 Pro LINQ: Language Integrated Query in C# 2008 www .apress. com SOURCE CODE ONLINE Companion eBook ... print for content only—size & color not accurate spine = 1.176" 6 24 page count Books for professionals By professionals ® Pro LINQ: Lan...

Ngày tải lên: 06/08/2014, 08:22

... into the entity classes at key points in time. Finally, query expressions provide that warm fuzzy feeling when first seeing a LINQ query that makes you want to get on board with LINQ. Nothing ... next. Listing 3 -4. An Example Demonstrating the Query Results Changing Between Enumerations // Create an array of ints. int[] intArray = new int[] { 1,2,3 }; IEnumerable<int> ints...

Ngày tải lên: 06/08/2014, 08:22

... example. Reprinted Here for Convenience Is Listing 1-3 using System; using System .Linq; using System.Data .Linq; using nwind; Northwind db = new Northwind(@"Data Source=.\SQLEXPRESS;Initial Catalog=Northwind"); var ... zero since the sequence is empty. Listing 4- 49. An Example to Return an Empty Sequence of Strings IEnumerable<string> strings = Enumerable.Empty<string&...

Ngày tải lên: 06/08/2014, 08:22

... DataContext. Listing 14- 1 contains an example of inserting a record into the database. Listing 14- 1. Inserting a Record by Inserting an Entity Object into Table<T> // 1. Create the DataContext. Northwind ... 2:15 PM 41 6 CHAPTER 14 ■ LINQ TO SQL DATABASE OPERATIONS Standard Database Operations While I will be covering the details of performing LINQ to SQL queries in detail i...

Ngày tải lên: 06/08/2014, 08:22

... mapping file to perform a LINQ to SQL query without using any attributes. Listing 16-9. The Third DataContext Constructor Prototype Connecting to a Database and Using a Mapping File string ... Source=.\SQLEXPRESS;Initial Catalog=Northwind ;Integrated Security=SSPI;", nwindMap); IQueryable<Linqdev.Customer> query = from cust in db.GetTable<Linqdev.Customer>() wh...

Ngày tải lên: 06/08/2014, 08:22