How do I decompile a .NET EXE into readable C# source code?
I wrote a C# application for a client a couple of years ago, but I no longer have the source code. All I have is the EXE that I deployed on the client's PC. Is there a way I can generate C# source code from the EXE?
Reflector and its add-in FileDisassembler.
Reflector will allow to see the source code. FileDisassembler will allow you to convert it into a VS solution.
When Red Gate said there would no longer be a free version of .Net Reflector, I started using ILSpy and Telerik's JustDecompile. I have found ILSpy to decompile more accurately than JustDecompile (which is still in Beta). Red Gate has changed their decision and still have a free version of .Net Reflector, but now I like ILSpy.
From the ILSpy website (https://github.com/icsharpcode/ILSpy/):
ILSpy is the open-source .NET assembly browser and decompiler.
ILSpy Features
- Assembly browsing
- IL Disassembly
- Decompilation to C#
- Supports lambdas and 'yield return'
- Shows XML documentation
- Saving of resources
- Search for types/methods/properties (substring)
- Hyperlink-based type/method/property navigation
- Base/Derived types navigation
- Navigation history
- BAML to XAML decompiler
- Save Assembly as C# Project
- Find usage of field/method
- Extensible via plugins (MEF)
Update:
April 15, 2012, ILSpy 2.0 was released. New features compared with version 1.0:
- Assembly Lists
- Support for decompiling Expression trees
- Support for lifted operatores on nullables
- Decompile to Visual Basic
- Search for multiple strings separated by space (searching for "Assembly manager" in ILSpy.exe would find AssemblyListManager)
- Clicking on a local variable will highlight all other occurrences of that variable
- Ctrl+F can be used to search within the decompiled code view
Update:
- ILSpy 2.1 supports async/await decompilation
Reflector is no longer free in general, but they do offer it for free to open source developers: http://reflectorblog.red-gate.com/2013/07/open-source/
But a few companies like DevExtras and JetBrains have created free alternatives:
DevExtras CodeReflect
JetBrains DotPeek