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?
270
votes
Ok. Look here ... Teleriks JustDecompile actually decompiled the DLL's that Red Gates Reflector completely screwed up ... there were numerous issues with Reflector ... JustDecompile ... flawless so far ...
- Marc Johnston
I have been using JustDecompile for quite a long time and it is really good at decompiling and package the source files as a ready to compile csproject. It is really active in development and there seems to be no open issues in their repo github.com/telerik/JustDecompileEngine
- David Chelliah
8 Answers
202
votes
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.
149
votes
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
66
votes
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:
36
votes
Reflector and the File Disassembler add-in from Denis Bauer. It actually produces source projects from assemblies, where Reflector on its own only displays the disassembled source.
ADDED: My latest favourite is JetBrains' dotPeek.
30
votes
26
votes
I'm surprised no one has mentioned Microsoft's ildasm. It may not be as pretty as ILSpy or Reflector, but it comes with Visual Studio so many developers already have it.
To run it (assuming VS 2013, should be similar for other versions):
- Select Start > All Programs > Visual Studio 2013 > Visual Studio Tools.
- Double-click on Developer Command Prompt for VS2013.
- Run "ildasm" from the resulting command prompt.
- In the tool, select File > Open and open your executable or DLL.
Now you can navigate the DLL structure. Double-click on class members to see the IL. Use File > Dump to export IL to a file.
15
votes
5
votes
I'm surprised no one has mentioned dnSpy. dnSpy is a debugger and .NET assembly editor. You can use it to edit and debug assemblies even if you don't have any source code available.
Main features:
- Debug .NET and Unity assemblies
- Edit .NET and Unity assemblies
- Light and dark themes
It is open source and one of most widely used reverse engineering tool for dot net.
