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Razor is an ASP.NET programming syntax used to create dynamic web pages with the C# or VB.NET programming languages. Razor was introduced in June 2010^[4] and was released for Microsoft Visual Studio 2010 in January 2011.^[5] Razor is a simple-syntax view engine and was released as part of MVC 3 and the WebMatrix tool set.^[5]

Razor became a component of AspNetWebStack and then became a part of ASP.NET Core.^[6]

The Razor syntax is a template markup syntax, based on the C# programming language, that enables the programmer to use an HTML construction workflow. Instead of using the ASP.NET Web Forms (.aspx) markup syntax with <%= %> symbols to indicate code blocks, Razor syntax starts code blocks with an @ character and does not require explicit closing of the code-block.

The idea behind Razor is to provide an optimized syntax for HTML generation using a code-focused templating approach, with minimal transition between HTML and code.^[7] The design reduces the number of characters and keystrokes, and enables a more fluid coding workflow by not requiring explicitly denoted server blocks within the HTML code.^[4] Other advantages that have been noted:^[8]

• Supports IntelliSense – statement completion support
• Supports "layouts" – an alternative to the "master page" concept in classic Web Forms (.aspx)
• Unit testable

• Blazor

Wikibooks has a book on the topic of: .NET Development Foundation

• Introduction to Razor Pages in ASP.NET Core at Microsoft Docs
  • ASP.NET Web Pages at Microsoft Docs
• Overview of ASP.NET Core MVC at Microsoft Docs
  • ASP.NET MVC at Microsoft Docs
• Razor on GitHub (archived). Current development is held at aspnetcore on GitHub