1. Code Behind:

1. The HTML and controls are in the .aspx file, and the code is in a separate .aspx.vb or .aspx.cs file.
2.The code for the page is compiled into a separate class from which the .aspx file derives.
3. All project class files (without the .aspx file itself) are compiled into a .dll file, which is deployed to the server without any source code. When a request for the page is received, then an instance of the project .dll file is created and executed.

2. Inline code(Single file):

1.The code is in blocks in the same .aspx file that contains the HTML and controls.
2.The .aspx file derives from the Page class.
3.When the page is deployed, the source code is deployed along with the Web Forms page, because it is physically in the .aspx file. However, you do not see the code, only the results are rendered when the page runs.