For almost as long as there has been a .NET development environment there have been free developer tools that used Reflection to help developers understand the nature of the beast they were dealing with. The tool that almost everyone started with was .NET Reflector, which was originally written by Lutz Roeder. In 2008, Red Gate Software announced they were taking over future Reflector development, and that Reflector would remain free.
Early in 2011 Red Gate announced that .NET Reflector would become a paid-for product, and that the free version would no longer be available. They also announced that previously downloaded free versions would time out. After being on the receiving end of what had to be an amazing stream of bile and vitriol due to the idea of reneging on their original promise, they relented and announced that previously downloaded versions would be automatically updated to become permanent.
As we near the one year anniversary of Red Gate’s questionable marketing decision, it probably didn’t lead to many sales of their paid version, but sudden lack of an established free reflection tool did lead to the creation of several free alternatives:
A new version of JetBrains dotPeek was released on December 29th and is the cream of the replacement crop so far. It gives you some of the same functionality you’ll find in their ReSharper product: The ability to navigate to a specific type, assembly, symbol, or type member; to move between declarations, implementations, derived, and base classes in inheritance chains. It has no installer, so once you download and unpack the ZIP file and you’re good to go. DotPeek disassembled my test dll with very good fidelity, but didn’t insert curly braces in all the places where I’d like to see them. Maybe a future version will give me the abiltiy to specify code formatting rules the same way ReSharper does. In general, the functionality of dotPeek gives you the idea that you might be in a mini version of Visual Studio.
DevExtras CodeReflect is available as an MSI installer or a ZIP file. It was quick to download and unpack. It performed well, but didn’t do the full colorization of the code the way dotPeek and JustDecompile did. One nice feature is that it allows you to quickly switch back and forth between MSIL, C#, and VB.NET code. The decompilation fidelity was good, but it did generate some intermediate variables that didn’t exist in the original code.
LSpy is an open-source project that requires .NET Framework 4.0. You can download the binaries or the source code from SourceForge. The program will check for updates once a week if you prefer. The performance was good, and the decompilation fidelity was very good, but the code colorization was a little weird. But I can live with that. You can quickly switch back and forth between generating MSIL and C# code.
The installer for Telerik JustComplile asks for too much registration info and takes too long to do its work, IMHO. Telerik appears to be viewing their product as too much of a marketing opportunity… to the point that it ceases to be a marketing opportunity with me. You’ll see “Just kick back and relax. Good things take time. Please be patient.” as the installation proceeds. You also need to be patient as the the installed program goes through the process of “Loading assemblies.” JustDecompile had a bit of trouble with decompiling a relatively simple class, but it did come close and the software is still in beta. Once everything was loaded the performance seemed very good.