Correct Answer: After you add a LINQ to SQL Classes item to a project and open the O/R Designer, the empty design surface represents an empty DataContext class ready to be configured The DataContext class is a LINQ to SQL class that acts as a conduit between a SQL Server database and the LINQ to SQL entity classes mapped to that database This class contains the connection string information and the methods for connecting to a database and manipulating the data in the database It is configured with connection information provided by the first item that is dragged onto the design surface

Correct Answer: The standard query operators in LINQ are the extension methods that form the LINQ pattern These operators form an API that enables querying of any NET array or collection It operates on sequences and allows you to perform operations, such as determining if a value exists in the sequence and performing an aggregated function, such as a summation over a sequence

Correct Answer: The standard query operators implement the IEnumerable or the IQueryable interface in C# and the IEnumerable(Of T) or the IQueryable(Of T) interface in Visual Basic

Correct Answer: Windows services, previously known as NT services, are applications that are installed on the system as system services In other words, Windows services are applications that run in the background with the Windows operating system The primary use of Windows services is to reduce the consumption of memory required for performing backend operations Let's take an example to understand this easily Suppose you want to perform a variety of functions, such as monitor the performance of your computer or application, check the status of an application, and manage various devices, such as printers In such a case, you can use Windows services to reduce memory consumption In addition, Windows services can run on your system even if you have not logged on to your computer In addition, these services do not have any user interface

Correct Answer: The ServiceInstaller class, also known as the project installer class, is used to install a Windows service

Correct Answer: ASPNET AJAX, mostly called AJAX, is a set of extensions of ASPNET It is developed by Microsoft to implement AJAX functionalities in Web applications ASPNET AJAX provides a set of components that enable the developers to develop applications that can update only a specified portion of data without refreshing the entire page The ASPNET AJAX works with the AJAX Library that uses object-oriented programming (OOP) to develop rich Web applications that communicate with the server using asynchronous postback

Correct Answer: The following validation controls are available in ASPNET AJAX 40: => FilteredTextBoxExtender - Enables you to apply filtering to a text box => MaskedEditExtender and MaskedEditValidator - Restricts a user to enter only a certain pattern of characters in the TextBox by applying a mask to the input => ValidatorCalloutExtender - Attaches to the ASPNET validators so that the error messages are not displayed as a simple text but as a balloon-style ToolTip => NoBot - Prevents the spam/bot from filling the input forms automatically and uses the Completely Automated Public Turing test to tell Computers and Humans Apart (CAPTCHA), which is a type of challenge-response test to ensure that the response is not generated by the computer => PasswordStrengthExtender - Measures the strength of the password text entered within the text box by validating with the different strength specified parameters

Correct Answer: You should not use AJAX if: => You want the page to show in a search engine, such as Google, because WebCrawler does not execute JavaScript code => The browser does not support JavaScript => You want to create a secure application

Correct Answer: Assemblies are the basic building blocks required for any application to function in the NET realm They are partially compiled code libraries that form the fundamental unit of deployment, versioning, activation scoping, reuse, and security Typically, assemblies provide a collection of types and resources that work together to form a logical unit of functionality They are the smallest deployable units of code in NET Compared to the executable files assemblies are far more reliable, more secure, and easy to manage An assembly contains a lot more than the Microsoft Intermediate Language (MSIL) code that is compiled and run by the Common Language Runtime (CLR) In other words, you can say that an assembly is a set of one or more modules and classes compiled in MSIL, and metadata that describes the assembly itself, as well as the functionalities of the assembly classes

Correct Answer: The following are the two types of assemblies: => Private Assembly - Refers to the assembly that is used by a single application Private assemblies are kept in a local folder in which the client application has been installed => Public or Shared Assembly - Refers to the assembly that is allowed to be shared by multiple applications A shared assembly must reside in Global Assembly Cache (GAC) with a strong name assigned to it For example, imagine that you have created a DLL containing information about your business logic This DLL can be used by your client application In order to run the client application, the DLL must be included in the same folder in which the client application has been installed This makes the assembly private to your application Now suppose that the DLL needs to be reused in different applications Therefore, instead of copying the DLL in every client application folder, it can be placed in the global assembly cache using the GAC tool These assemblies are called shared assemblies