Visual Studio has its own integrated ASP.NET Runtime engine, which helps to run any ASP.NET web application with in Visual Studio. While running application from Visual Studio, you must have seen a popup notification in System Tray (As shown in below image) , which is notification of ASP.NET Development Server.
This ASP.NET Development Server is nothing but a executable file (WebDev.WebServer) which used by Visual Studio to execute you web application when it’s running in the context of Visual Studio. You can find the executable file at <\Program Files (x86)\Common Files\microsoft shared\DevServer\10.0> . This folder contain two different executable
- WebDev.WebServer20.EXE
- WebDev.WebServer40.EXE
WebDev.WebServer20 is targeted to CLR 2.0, which means all the ASP.NET Application which are targeted till FW .NET 3.5 will be taking care by WebDev.WebServer20.EXE and WebDev.WebServer40.EXE for ASP.NET 4.0 based application.
Now, let’s see how we can use these executable to run an ASP.NET 4.0 Application with out using Visual Studio. 
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