IL:-stands for Intermediate Language.This is the language code generated by the C# compiler or any .NET-aware compiler. All .NET languages generate this code. This is the code that is executed during runtime.You can view this MSIL code with the help of a utility called Intermediate Language Disassembler (ILDASM). This utility displays the application's information in a tree-like fashion. Because the contents of this file are read-only, a programmer or anybody accessing these files cannot make any modifications to the output generated by the source code.