Protect DLL from decompile in ASP.Net

Dear All,

I want to protect and put a password to block any decompiling possibilities (for example using decompile software) of all C# codebehind files.

Is it possible to achieve this and still be able to run the website as normaly?

I am using Visual studio to precompile the files, but I guess it is still possible for someone to decompile them.

Thanks in advance