What is the ‘page lifecycle’ of an ASP.NET MVC?

What is the ‘page lifecycle’ of an ASP.NET MVC?
Following process are performed by ASP.Net MVC page:
1) App initialization
2) Routing
3) Instantiate and execute controller
4) Locate and invoke controller action
5) Instantiate and render view

Remove MVC Action from Cache

For removing the Cache from the action so it get refresh each time, use the below stuff

public class NoCacheAttribute : ActionFilterAttribute
{
    public override void OnActionExecuted ( ActionExecutedContext context )
    {
        context.HttpContext.Response.Cache.SetCacheability( HttpCacheability.NoCache );
    }
}

[HttpGet]
[NoCache]
public JsonResult GetSomeStuff ()
{
    ...
}

What is new in ASP.NET 3.5

ASP.NET AJAX

In ASP.NET 2.0, ASP.NET AJAX was used as an extension to it. You had to download the extensions and install it. However in ASP.NET 3.5, ASP.NET AJAX is integrated into the .NET Framework, thereby making the process of building cool user interfaces easier and intuitive.

The integration between webparts and the update panel is much smoother. Another noticeable feature is that you can now add ASP.NET AJAX Control Extenders to the toolbox in VS2008. Even though this is an IDE specific feature, however I feel it deserves a mention over here for developers, who had to add extenders using source view earlier. It is also worth noting that Windows Communication Foundation (WCF) now supports JSON along with other standard protocols like  SOAP, RSS and POX.

New Controls

The ListView and DataPager are new controls added along with a new datasource control called the LinqDataSource.

ListView

The ListView control is quiet flexible and contains features of the Gridview, Datagrid, Repeater and similar list controls available in ASP.NET 2.0. It provides the ability to insert, delete, page (using Data Pager), sort and edit data. However one feature of the ListView control that stands apart, is that it gives you a great amount of flexibility over the markup generated. So you have a complete control on how the data is to be displayed. You can now render your data without using the tag. You also get a rich set of templates with the ListView control.

DataPager

DataPager provides paging support to the ListView control. The best advantage is that you need not have to keep it ‘tied’ with the control on which the paging is being done. You can keep it anywhere on the page.

DataPager gives you a consistent way of paging with the controls that support it. Currently only ListView supports it as it implements the IPageableItemContainer. However support is likely to be added to other List controls as well.

LINQ

LINQ (Language Integrated Query) adds native data querying capability to C# and VB.NET along with the compiler and Intellisense support. LINQ is a component of .NET 3.5. LINQ defines operators that allow you to code your query in a consistent manner over databases, objects and XML.  The ASP.NET LinqDataSource control allows you to use LINQ to filter, order and group data before binding to the List controls.

ASP.NET Merge Tool

ASP.NET 3.5 includes a new merge tool (aspnet_merge.exe). This tool lets you combine and manage assemblies created by aspnet_compiler.exe. This tool was available earlier as an add-on.

New Assemblies

The new assemblies that would be of use to ASP.NET 3.5 developers are as follows:

·         System.Core.dll - Includes the implementation for LINQ to Objects

·         System.Data.Linq.dll - Includes the implementation for LINQ to SQL

·         System.Xml.Linq.dll - Includes the implementation for LINQ to XML

·         System.Data.DataSetExtensions.dll - Includes the implementation for LINQ to DataSet

·         System.Web.Extensions.dll: Includes the implementation for ASP.NET AJAX (new enhancements added) and new web controls as explained earlier.

Some Other Important Points

1.    ASP.NET 3.5 provides better support to IIS7. IIS7 and ASP.NET 3.5 modules and handlers support unified configuration.

2.    You can have multiple versions of ASP.NET on the same machine.

3.    For those who are wondering what happened to ASP.NET 3.0, well there isn’t anything called ASP.NET 3.0.

4.    VS 2002 worked with ASP.NET 1.0, VS 2003 worked with ASP.NET 1.1, and VS 2005 worked with ASP.NET 2.0. However VS 2008 supports multi-targeting, i.e it works with ASP.NET 2.0, and ASP.NET 3.5. 

C#'s const vs. readonly

A quick synopsis on the differences between 'const' and 'readonly' in C#:
'const':
Can't be static.
Value is evaluated at compile time.
Initiailized at declaration only.

'readonly':
Can be either instance-level or static.
Value is evaluated at run time.
Can be initialized in declaration or by code in the constructor.

Handlers vs. Modules

Modules are units of code that have registered for one or more pipeline events. They perform authentication, authorization, logging, etc. There is one task that is reserved for a special module, known as a handler. The handler’s unique job is to retrieve the resource that is requested in the URL. All resources served by IIS are mapped to a handler in configuration. If the configuration mapping does not exist, requests for the resource will receive a 404 HTTP status. In addition to the configuration mapping, which takes place before the pipeline begins, the handler mapping can be changed during request execution in the MAP_REQUEST_HANDLER event. This allows scenarios such as URL rewriting to work. Handlers are notified, or executed, in the EXECUTE_REQUEST_HANDLER step. (Note that only the mapped handler is notified, as you would expect.)

What is an application domain?

An application domain is the CLR equivalent of an operation system’s
process. An application domain is used to isolate applications from one
another. This is the same way an operating system process works. The
separation is required so that applications do not affect one another.
This separation is achieved by making sure than any given unique
virtual address space runs exactly one application and scopes the
resources for the process or application domain using that address space.

What are Object Initializers?

The Object initializers are the features for programming concepts which was introduced in C#.Net.

The aim of using Object Initializers is to initializing the accessible fields or properties
of an object without the need to write any parametrized constructor or separate
statements.

Sample:

using System;
class Student
{
int rollno;
string stdName;
static void Main()
{
Student s = new Student(){rollno=1,stdName="Ramesh" }; //Object Initializer
}
}

What is the purpose of IIS application pools?

We use application pools for isolation purpose. Every application within an application pool used the same worker process. Each worker process operates as a separate instance of the worker process executable, W3wp.exe, the worker process that services one application pool is separated from the worker process that services another.

In simplest words we use application pools for ISOLATION purpose.

Constructor in C#

• A constructor is a special method whose task is to initialize the object of its class.
• It is special because its name is the same as the class name.
• They do not have return types, not even void and therefore they cannot return values.
• They cannot be inherited, though a derived class can call the base class constructor.
• Constructor is invoked whenever an object of its associated class is created.
• Note: There is always atleast one constructor in every class. If you do not write a constructor, C# automatically provides one for you, this is called default constructor. Eg: class A, default constructor is A().

this Keyword in ASP.NET

this Keyword

Each object has a reference “this” which points to itself.

Two uses of this keyword.

o Can be used to refer to the current object.

o It can also be used by one constructor to explicitly invoke another constructor of the same class.