linq to objects

= q.todictionary (p = p.productid);foreach(intKeyinchQdictionary.keys) {Console. WriteLine (key);}Statement Description: This sample uses todictionary to directly evaluate the query and key expression direct key expressions as dictionaryAdo. NET and LINQ to SQLLINQ to SQL is based on the services provided by the ADO provider model. As a result, we were able to mix LINQ to SQL code with existing ADO-out app

LINQ to ADO includes two separate technologies: LINQ to DataSet and LINQ to SQL. Using LINQ to Datasets, you can perform rich and optimized queries against a dataset, and LINQ to SQL can directly query the SQL Server database schema.LINQ providers that are implemented by

sources, such as memory Objects (LINQ to Objects), databases (LINQ to SQL), XML files (LINQ to XML), and file systems. It is a set of functions introduced in Visual Studio 2008. It provides powerful query functions for C # and Visual Basic syntax, and has withstood the test

Linq learning summary 1-refer to the detailed description of Linq technology, 1-linqKey points:1. The set of linq operations must implement the IEnumerable interface. Therefore, before 3.0, the set that implements this interface must be converted to a Linq-enabled set through the Cast or TypeOf method; 2. the query exp

Linq learning summary 1-refer to the detailed description of Linq technology, 1-linq Two key points: 1. The set of linq operations must implement the IEnumerable interface. Therefore, before 3.0, the set that implements this interface must be converted to a Linq-enabled set

...Understanding C #3.0 features (8) partial Method [LINQ via C # series] The is a very simple feature. from partial class to partial method partial class is introduced by C #2.0. with the partial keyword, the definition of one type is able to be divided into several files. for example, if creating...Understanding LINQ to objects (1) Programming Paradigm [

LINQ to datasets require the use of System.Core.dll, System.Data.dll and System.Data.DataSetExtensions.dll, add references System.Data and System.Data.DataSetExtensions to the project.1. DataTable Read ListDataSet ds = new DataSet ();//Omit the DS's fill code datatable products = ds. tables["Product"];ienumerableDataSet ds = new DataSet ();//Omit the DS's fill code datatable products = ds. tables["Product"];var rows = products. AsEnumerable () . Se

LINQ to objects, LINQ to datasets, LINQ to SQL, LINQ to entities, and LINQ to XML. A. Net Language Integrated Query Based on relational data. It is used to manage relational data in the form of

As we all know, LINQ can be used to query database objects (I am referring to the model object in Entity Framework) or ienumerable objects in memory. There will be no problem when the two queries are separate, but when they are mixed together (generally using keywords to join connections), there will be more to note. Scenario 1: Join (join)

3.1 extensions of. Net by LINQ Sequence 3.2 3.2.1 ienumerable The array objects all implement the ienumerable 3.2.3 delayed query execution The LINQ query statement is very dependent on delayed job seeking. In the case of LINQ, we call it deferred query execution, or deferredquery evaluation ). This is one of the mos

", new XAttribute("Type", "Home")), new XElement("phone", "425-555-0145", new XAttribute("Type", "Work")), new XElement("Address", new XElement("Street1", "123 Main St"), new XElement("City", "Mercer Island"), new XElement("State", "WA"), new XElement("Postal", "68042") ) ) ); Note that the code used to construct the XML tree shows the structure of the basic XML.

LINQ to SQL Provides a run-time infrastructure for managing relational data as objects. In LINQ to SQL, the data model of a relational database was mapped to an object model expressed in the programming language of the developer. When you execute the application, LINQ to SQL translates language-integrated queries in th

As you know, LINQ can be used to query database objects (which I refer to as model objects in the Entity Framework), or to query IEnumerable objects in memory.There is nothing wrong with both queries, but when mixed together (usually with keywords to join connections), there is more to note.Scenario 1:

find the good and bad between dynamic running and static language if we don't pay attention to the troubles in the design frame. The obvious example is that when we define an object of a data type, it can no longer be used for other types of use at the later runtime, see a simple example: View CodeAt runtime we can design object types at will, and I boldly assume that you can use dynamic runtime features to design a similar AI system, provide a basic prototype, and then build any tree of

. Lambda This. enumerable = expression2.Compile (); // (1) Key}Return this. enumerable. GetEnumerator ();}In the "(1) Emphasis" in the above code, we can clearly see that the expression tree is dynamically compiled and then executed, here we can see why the IEnumerable Why do we need dynamic LINQ queries? As mentioned above, we cannot write Lambda expressions at runtime. We all know that Lambda expressions are compiled into Expression Tree

(Original: ash insects home http://hi.baidu.com/grayworm)LINQ to objects is the core of the LINQ family. Other LINQ also use the same query syntax as that of LINQ to objects.In the end, the compiler translates the LINQ syntax into

shorter, meaningful, and expressive syntax to manipulate data. The following is a simple typical software solution for the LINQ query, which returns a collection of names of all clients in Italy in the country: var query = from c in Customers where c.Country == "Italy" select c.CompanyName; Do not worry about syntax and keywords (suchVaR keyword). The query result is a strings set. In C #, you can use a foreach statement to enumerate the result:

call DeleteOnSubmit: // With l2s )); 101)); Context. SubmitChanges (); // With EF )); 101)); Context. SaveChanges ();comparison of LINQ to SQL and Entity Framework APIsAs we saw in these two articles, l2s and EF are very similar to LINQ queries and data updates, except that they create

. In addition, it also explains the scalability of LINQ, which can be used for more advanced data processing. The book has a reasonable organizational structure and smooth writing, making readers feel like they are on a technical trip. In an in-depth and thorough explanation, the example is used to provide C # and VB for the same topic.. Net instance, and provide comments on the key points of the instance, truly achieving the realm of simplicity... Th

Project Description $ LINQ is a javascript version of. Net's LINQ to objects, with some query operations stored red by morelinq (an extension to LINQ to objects ). What is $ LINQ? $ LINQ