View source for ASP.NET

{{Short description|Open-source web application framework}}
{{distinguish|UNESCO ASPNet}}
{{for|its rewrite|ASP.NET Core}}
{{Infobox software
| name = ASP.NET (software)
| logo = 
| developer = [[Microsoft]], [[Scott Guthrie]]
| released = {{Start date and age|2002|1|5}}
| latest_release_version = 4.8.1
| latest_release_date = {{Start date and age|2022|08|09}}<ref>{{cite web |title=.net framework download page|url=https://dotnet.microsoft.com/en-us/download/dotnet-framework/net481}}</ref>
| programming language = [[List of CLI languages|.NET languages]]
| operating system = [[Microsoft Windows]], [[Linux]], [[macOS]]
| platform = [[.NET Framework]]
| genre = [[Web framework]]
| license = [[Proprietary software]]<ref>{{cite web|title=Microsoft .NET Framework Redistributable EULA|url=https://msdn.microsoft.com/en-us/library/ms994405.aspx|website=[[MSDN]]|date=13 September 2006 |publisher=[[Microsoft]]|access-date=February 28, 2015|archive-date=April 2, 2015|archive-url=https://web.archive.org/web/20150402161923/https://msdn.microsoft.com/en-us/library/ms994405.aspx|url-status=live}}</ref>
}}
{{Infobox file format
| name          = ASP.NET (file format)
| icon          = 
| logo          = 
| _noextcode    = on
| extension     = <code>.aspx</code>, <code>.asmx</code>, <code>.aspc</code>,<ref name=devx>{{Cite web |title=Introduction to ASP+ |url=http://archive.devx.com/asp/articles/ck072600/ck072600.asp |archive-url=https://web.archive.org/web/20030202065505/http://archive.devx.com/asp/articles/ck072600/ck072600.asp |archive-date=2003-02-02 |access-date=2025-08-13 |website=DevX |first=Chris |last=Kinsman |date=July 2000}}</ref> <code>[[ASP.NET Razor|.cshtml]]</code>, <code>[[ASP.NET Razor|.vbhtml]]</code>
| mime          = text/html
| magic         = 
| owner         = [[Microsoft]]
| released      = <!-- {{Start date|YYYY|mm|dd|df=yes/no}} -->
| latest release version = 
| latest release date = <!-- {{Start date and age|YYYY|mm|dd|df=yes/no}} -->
| genre         = 
| container for = 
| contained by  = 
| extended from = 
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| standard      = 
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| url           = 
}}

'''ASP.NET''' is a [[server-side scripting|server-side]] [[web-application framework]] designed for [[web development]] to produce [[dynamic web page]]s. It was developed by [[Microsoft]] to allow [[programmer]]s to build dynamic [[web site]]s, [[web application|applications]] and [[web service|service]]s. The name stands for Active Server Pages Network Enabled Technologies.{{citation needed|date=August 2025}}

ASP.NET was first announced to the public under the codename ASP+, and is a re-implementation of Microsoft's [[Active Server Pages]] (ASP) technology.<ref name=devx/> ASP.NET is built on the [[Common Language Runtime]] (CLR), allowing programmers to write ASP.NET code using any supported [[List of CLI languages|.NET language]].<ref>{{cite book |title = Pro ASP.NET 2.0 in C# 2005 |edition = 1st |last1 = MacDonald |first1 = Matthew |first2 = Mario |last2 = Szpuszta |year = 2005 |publisher = Apress |isbn = 1-59059-496-7 |url-access = registration |url = https://archive.org/details/proaspnet20inc200000macd |pages=5–6 |quote=[...] ASP.NET pages and web services are executed within the CLR (common language runtime), so they can be authored in any language that has a CLR-compliant compiler. [...] ASP.NET gives you the ability to code in any supported .NET language (including Visual Basic, C#, J#, and many other languages that have third-party compilers). }}</ref> The ASP.NET [[SOAP]] extension framework allows ASP.NET components to process SOAP messages.

In 2016, Microsoft released [[ASP.NET Core]] as ASP.NET's successor. This new version is a re-implementation of ASP.NET as a modular [[web framework]], together with other frameworks like [[Entity Framework]]. The new framework uses the new open-source [[.NET Compiler Platform]] (codename "Roslyn") and is [[cross platform]]. [[ASP.NET MVC]], ASP.NET Web API, and ASP.NET Web Pages (a platform using only [[ASP.NET Razor|Razor]] pages) have merged into a unified MVC ([[model–view–controller]]) 6.<ref name="asp.net">{{cite web|title=ASP.NET 5 Overview|first=Tom|last=FitzMacken|date=2014-12-11|website=ASP.NET|url-status=dead|archive-url=https://web.archive.org/web/20141115023406/http://www.asp.net/vnext/overview/aspnet-vnext/aspnet-5-overview#unify|url=http://www.asp.net/vnext/overview/aspnet-vnext/aspnet-5-overview#unify|archive-date=2014-11-15}}</ref>

== Programming models ==
{{see also|ASP.NET Web Forms}}
ASP.NET supports a number of programming models for building web applications:<ref>{{cite web |title=Choose between ASP.NET and ASP.NET Core |archive-url=https://web.archive.org/web/20180509012506/https://docs.microsoft.com/en-us/aspnet/core/choose-aspnet-framework?view=aspnetcore-2.1|url=https://docs.microsoft.com/en-us/aspnet/core/choose-aspnet-framework?view=aspnetcore-2.1|archive-date=2018-05-09|website=Microsoft Docs|url-status=dead| date=2018-03-14|language=en-us}}</ref>
* [[ASP.NET Web Forms]] – A framework for building modular pages out of components, with UI events being processed server-side. This framework is not included in the ASP.NET Core versions; it only works in the "classic" ASP.NET, on Windows.
* [[ASP.NET MVC]] – allows building web pages using the [[model–view–controller]] design pattern.
* [[ASP.NET Web Pages]] – A lightweight syntax for adding dynamic code and data access directly inside HTML markup.<ref>{{cite web |title=ASP.NET Web Pages (Razor) FAQ |url=https://docs.microsoft.com/en-us/aspnet/web-pages/overview/getting-started/aspnet-web-pages-razor-faq#Whats_the_difference_between_ASP.NET_Web_Pages,_ASP.NET_Web_Forms,_and_ASP.NET_MVC |website=docs.microsoft.com |language=en-us}}</ref>
* [[ASP.NET Web API]] – A framework for building [[Web API]]s on top of the [[.NET Framework]].<ref>{{cite web |title=Get Started with ASP.NET Web API 2 (C#) |url=https://docs.microsoft.com/en-us/aspnet/web-api/overview/getting-started-with-aspnet-web-api/tutorial-your-first-web-api |website=docs.microsoft.com |date=30 September 2022 |language=en-us |first=Wasson |last=Mike }}</ref>
* [[ASP.NET WebHooks]] – Implements the [[Webhook]] pattern for subscribing to and publishing events via HTTP.
* [[SignalR]] – A real-time communications framework for bi-directional communication between client and server.

Other ASP.NET extensions include:
* [[HTTP handler|ASP.NET Handler]] – Components that implement the <code>System.Web.IHttpHandler</code> interface. Unlike ASP.NET Pages, they have no HTML-markup file, no events and other supporting. All they have is a code-file (written in any [[List of CLI languages|.NET-compatible language]]) that writes some data to the server HTTP response. HTTP handlers are similar to [[ISAPI]] extensions.
* [[ASP.NET AJAX]] – An extension with both client-side as well as server-side components for writing ASP.NET pages that incorporate [[AJAX (programming)|Ajax]] functionality.
* [[ASP.NET Dynamic Data]] – A [[scaffold (programming)|scaffolding]] extension to build data driven web applications.

== IIS integrated pipeline ==
On [[Internet Information Services|IIS]]&nbsp;6.0 and lower, pages written using different versions of the ASP framework cannot share [[#Session state|session state]] without the use of third-party libraries. This does not apply to ASP.NET and ASP applications running side by side on IIS&nbsp;7. With IIS&nbsp;7.0, modules may be run in an integrated pipeline that allows modules written in any language to be executed for any request.<ref>{{cite web|url=http://learn.iis.net/page.aspx/244/how-to-take-advantage-of-the-iis7-integrated-pipeline|title=How to Take Advantage of the IIS 7.0 Integrated Pipeline|work=iis.net|date=14 June 2022|access-date=26 January 2009|archive-date=24 March 2010|archive-url=https://web.archive.org/web/20100324031657/http://learn.iis.net/page.aspx/244/how-to-take-advantage-of-the-iis7-integrated-pipeline|url-status=dead}}</ref>

== Third-party frameworks ==
It is not essential to use the standard Web forms development model when developing with ASP.NET. Noteworthy frameworks designed for the platform include:
* [[Base One Foundation Component Library]] (BFC) is [[rapid application development|RAD]] framework for building .NET [[database]] and [[distributed computing]] applications.
* [[DotNetNuke]] is an open-source solution that provides both a web application framework and a content management system that allows for advanced extensibility through modules, skins, and providers.
* [[MonoRail (software)|Castle MonoRail]], an open-source [[model–view–controller|MVC]] framework with an execution model similar to [[Ruby on Rails]]. The framework is commonly used with [[Castle ActiveRecord]], an ORM layer built on [[NHibernate]].

== Versions ==
ASP.NET's release history tightly correlates with the [[.NET Framework]] releases:
<!--Template:Version - for version & release history. Documentation & examples: http://en.wikipedia.org/wiki/Template:Version-->
{| class="wikitable sortable"
|-
!  style="width:8%" | Date
!  style="width:8%" | Version
! class="unsortable" style="width:30%" | Remarks
! class="unsortable" style="width:45%" | New ASP.NET related features
|-
| January 16, 2002
| {{Version |o |1.0  | sortKey=1.00}}
| First version<br/>
released together with [[Visual Studio .NET]]
|
* [[Object-oriented programming|Object-oriented]] Web application development supporting [[inheritance (object-oriented programming)|inheritance]], [[polymorphism in object-oriented programming|polymorphism]] and other standard OOP features
** Developers are no longer forced to use Server.CreateObject(...), so early-binding and type safety are possible.
* Based on [[Microsoft Windows|Windows]] programming;  the developer can make use of DLL class libraries and other features of the Web server to build more robust applications that do more than simply rendering HTML (e.g., [[exception handling]])
|-
| April 24, 2003
| {{Version |o |1.1  | sortKey=1.10}}
| released together with [[Windows Server 2003]]<br/>
released together with [[Visual Studio .NET 2003]]
|
* Mobile controls
* Automatic input validation
|-
| November 7, 2005
| {{Version |o |2.0  | sortKey=2.00}}
|
codename [[Microsoft codenames|Whidbey]]<br/>
released together with [[Visual Studio 2005]] and [[Microsoft Visual Studio Express|Visual Web Developer Express]]<br/>
and [[Microsoft SQL Server|SQL Server 2005]]
|
* New data controls (GridView, FormView, DetailsView)
* New technique for declarative data access (SqlDataSource, ObjectDataSource, XmlDataSource controls)
* Navigation controls
* [[ASP master pages|Master pages]]
* Login controls
* Themes
* Skins
* Web parts
* Personalization services
* Full pre-compilation
* New localization technique
* Support for 64-bit processors
* Provider class model
|-
| November 21, 2006
| {{Version |o |3.0  | sortKey=3.00}}
| Released with [[Windows Vista]]
|
* [[Windows Presentation Foundation]] (WPF)
* [[Windows Workflow Foundation]] (WF)
* [[Windows Communication Foundation]], which can use ASP.NET to host services
* [[Windows CardSpace]], which uses ASP.NET for login roles
|-
| November 19, 2007
| {{Version |o |3.5  | sortKey=3.50}}
| Released with [[Visual Studio 2008]] and [[Windows Server 2008]]
|
* New data controls (ListView, DataPager)
* [[ASP.NET AJAX]] included as part of the framework
* Support for HTTP pipelining and syndication feeds.
* WCF support for RSS, JSON, POX and Partial Trust
* All the [[.NET Framework 3.5]] changes, like [[Language Integrated Query|LINQ]] etc.
|-
| August 11, 2008
| {{Version |o |3.5 Service Pack 1 | sortKey=3.51}}
| Released with Visual Studio 2008 Service Pack 1
|
* Incorporation of [[ASP.NET Dynamic Data]]
* Support for controlling browser history in an ASP.NET AJAX application
* Ability to combine multiple [[JavaScript]] files into one file for more efficient downloading
* New namespaces System.Web.Abstractions and System.Web.Routing
|-
| April 12, 2010
| {{Version |o |4.0  | sortKey=4.00}}
| Released with [[Visual Studio 2010]] 
Parallel extensions and other [[.NET Framework 4]] features
|
The two new properties added in the Page class are MetaKeyword and MetaDescription.
|-
| August 15, 2012
| {{Version |o |4.5   | sortKey=4.50}}
| Released with [[Visual Studio 2012]] and [[Windows Server 2012]] for [[Windows 8]]
Parallel extensions and other [[.NET Framework 4.5]] features
|
|-
| October 17, 2013
| {{Version |o |4.5.1 | sortKey=4.51}}
| Released with [[Visual Studio 2013]]<ref>{{cite web |title=Announcing release of ASP.NET and Web Tools for Visual Studio 2013 |url=http://blogs.msdn.com/b/webdev/archive/2013/10/17/announcing-release-of-asp-net-and-web-tools-for-visual-studio-2013.aspx}}</ref> for [[Windows Server 2012 R2]] and [[Windows 8.1]]
|
* [[Bootstrap (front-end framework)|Bootstrap]] 3.0
* Web API 2: [[OAuth]] 2.0, [[Open Data Protocol|OData]] improvements, [[Cross-origin resource sharing|CORS]]
* [[ASP.NET MVC|MVC]] 5: Attribute routing, authentication filters and filter overrides
* [[Entity Framework|EF]] 6
* [[SignalR]]
* [[Open Web Interface for .NET|OWIN]]
|-
| May 5, 2014<ref name="lifecycle">{{cite web|title=.net framework product lifecycle|url=https://support.microsoft.com/en-us/lifecycle/search?alpha=.net%20framework}}</ref>
| {{Version |co |4.5.2 | sortKey=4.52}}
|
|
* Higher reliability HTTP header inspection and modification methods
* New way to schedule background asynchronous worker tasks
|-
|July 20, 2015<ref name="lifecycle" />
|{{Version |co |4.6   | sortKey=4.60}}
|Released<ref>{{cite web |title=Announcing .NET Framework 4.6 |url=http://blogs.msdn.com/b/dotnet/archive/2015/07/20/announcing-net-framework-4-6.aspx}}</ref> with [[Visual Studio 2015]]<ref>{{cite web |title=Visual Studio 2015 and Visual Studio 2013 Update 5 Released |url=http://blogs.msdn.com/b/visualstudio/archive/2015/07/20/visual-studio-2015-and-visual-studio-2013-update-5-released.aspx |publisher=Microsoft |work=msdn.com|date=20 July 2015 }}</ref> and [[Entity Framework|EF]] 7 Previews for [[Windows Server 2016]] and [[Windows 10]]
|
* [[HTTP/2]] support when running on Windows 10
* More async task-returning APIs
|-
| November 30, 2015<ref name="lifecycle" />
|{{Version |co |4.6.1   | sortKey=4.61}}
|
|
|-
| August 2, 2016<ref name="lifecycle" />
|{{Version |co |4.6.2   | sortKey=4.62}}
| 
| 
* Improved async support (output-cache and session providers)
|-
| April 11, 2017<ref name="lifecycle" />
|{{Version |co |4.7   | sortKey=4.70}}
| Included in the Windows 10 Creators Update<ref>{{cite web|title=Announcing the .NET Framework 4.7|date=5 April 2017 |url=https://blogs.msdn.microsoft.com/dotnet/2017/04/05/announcing-the-net-framework-4-7/}}</ref>
|
* operating system support for TLS protocols
|-
| October 17, 2017<ref name="lifecycle" />
|{{Version |co |4.7.1   | sortKey=4.71}}
| Included in the Windows 10 Fall Creators Update.<ref>{{cite web|title=Announcing the .NET Framework 4.7.1|date=17 October 2017 |url=https://blogs.msdn.microsoft.com/dotnet/2017/10/17/announcing-the-net-framework-4-7-1/}}</ref>
|
* Improved accessibility
* Value tuple types serialization
* SHA-2 support 
|-
| April 30, 2018<ref name="lifecycle" />
|{{Version |co |4.7.2   | sortKey=4.72}}
|
|-
| August 09, 2022<ref name="lifecycle" />
|{{Version |c |4.8.1   | sortKey=4.80}}
| Released<ref>{{cite web|title=Announcing the .NET Framework 4.8|date=18 April 2019 |url=https://devblogs.microsoft.com/dotnet/announcing-the-net-framework-4-8/}}</ref>
|
* JIT and NGEN Improvements
* Updated [[zlib|ZLib]]
* Reducing FIPS Impact on Cryptography 
* Accessibility Enhancements for [[WinForms]]
* Service Behavior Enhancements for [[Windows Communication Foundation|WCF]]
* High DPI Enhancements, UIAutomation Improvements for [[Windows Presentation Foundation|WPF]]
|-
|November 18, 2015
|{{Version |o |5 RC1  | sortKey=4.90}}
|This version was later separated from ASP.NET and brought into a new project called [[ASP.NET Core]], whose versioning started at 1.0.<ref name="GHreleases">{{cite web |title=Releases |url=https://github.com/aspnet/Home/releases |website=GitHub}}</ref>
|An entirely new project with different development tenets and goals
|- class="sortbottom"
| colspan="4" | {{Version |l |show=111111}}
|}

== Other implementations ==
The [[Mono (software)|Mono]] Project supports "everything in .NET 4.7 except [[Windows Presentation Foundation|WPF]], [[Windows Workflow Foundation|WWF]], and with limited [[Windows Communication Foundation|WCF]] and limited ASP.NET async stack."<ref name="monoproject">{{cite web|title=Compatibility |url=http://www.mono-project.com/docs/about-mono/compatibility/ |website=Mono |access-date=13 August 2025 }}</ref> ASP.NET can be run with Mono using one of three options: [[Apache HTTP Server|Apache]] hosting using the [[mod_mono]] module, [[FastCGI]] hosting, and [[XSP (software)|XSP]].

== References ==
{{Reflist|30em}}

== External links ==
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* {{Official website|asp.net}}
* [http://msdn.microsoft.com/asp.net/ ASP.NET] on [[MSDN]]
* [http://www.codeproject.com/KB/aspnet/Whatis_New_ASP_Net_4.aspx Some of new features in ASP.NET 4 and vs 2010 IDE] {{Webarchive|url=https://web.archive.org/web/20181225171923/http://www.codeproject.com/KB/aspnet/Whatis_New_ASP_Net_4.aspx%20%0A |date=2018-12-25 }}

{{.NET Framework}}
{{Microsoft APIs|close}}
{{Microsoft development tools|close}}
{{Microsoft FOSS}}
{{Web frameworks}}
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