Research & Development for 3D & the Web

When you request and ASP.NET page, ASP.NET framework checks for a .NET class that corresponds with the page. Should it not be able to find one, the framework will automatically compile the page into a new class which gets stored in:

\WINDOWS\Microsoft.NET\Framework\v4.0.30128\Temporary ASP.NET files

This means that it only needs to compile the first time (or after any source code files are changed) and then it will return the pre-compiled page to any requesting the page afterwards from that point onwards until the source code for the application is modified.

This is called Dynamic compilation and is what allows ASP.NET to support thousands of simultaneous users. You can also turn off this dynamic compilation option if you need to. This can’t be done on pages which include server-side code but can contain ASP.NET controls and expressions.