You can create an assembly (DLL or EXE) from the IL file using the ILASM (ilasm.exe) utility. This utility is usually installed in the directory C:\WINNT\Microsoft.NET\Framework\v1.0.3705 (or the appropriate version number).

If you want to run this utility via command line it would help if you add the above path to your Environment Path variable. Here is an example command line:

ilasm TextProcessing.il /dll /output:TextProcessing.dll /resource:TextProcessing.res 

Here the .res resource file is optional.

Contributed from George Shepherd's Windows Forms FAQ