View .NET DLL source code using ILSpy

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ILSpy is a free alternative to Reflector for disassembling .NET binaries. The project started as a reaction to Red Gate turning the previously free Reflector tool commercial.

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ILSpy is a free alternative to Reflector

There was some controversy when Red Gate announced they were turning the extremely popular (and free) Reflector tool into a commercial product.

One reaction to this is the ILSpy project (IL standing for Intermediate Language - the abstraction code between source code, such as C# or VB, and actual machine code).

The ILSpy GUI will immediately be recognized by Reflector users, here seen disassembling a part of EPiServer CMS (on the subject of a source code browser for EPiServer):

ILSpy seen disassembling an EPiServer assembly

ILSpy is being actively developed, as recently as today the support for LINQ query expressions was explained at the SharpDevelop blog.

Download ILSpy

The latest ILSpy source code and binaries can be downloaded here. The screenshot above was taken while using the ILSpy M2 release, 1.0.0.737.

Easiest way to get started is to:

  1. Download the ILSpy binaries
  2. Unblock the ZIP file
  3. Extract the ZIP file somewhere
  4. Launch ILSpy.exe

Red Gate CEO explaining why Reflector can't be free

For those of you who are interested in Red Gate’s take on Reflector going commercial: here’s a video of Red Gate CEO Simon Galbraith explaining why Reflector cannot be freeware anymore (despite previous promises to keep Reflector free even after taking over the Reflector project from Lutz Roeder):