omnisharp-emacs is a port of the awesome OmniSharp server to the Emacs text editor. It provides IDE-like features for editing files in C# solutions in Emacs, provided by an OmniSharp server instance that works in the background.

Lacks a better UI and a good default configuration.

• Contextual code completion (i.e. auto-complete / IntelliSense) using popup.el or ido-mode or company-mode if it is installed.
  • Popup.el and company-mode provide a more sophisticated interface, with the possibility to fall back on all of ido's flexible matching power.
  • Also shows documentation like other IDEs
• Show type of the current symbol in the minibuffer
• Navigation helpers
  • Go to definition of a type/variable/method etc.
  • Find usages of the current symbol in the solution
  • Find implementations/derived types of the current type
  • Go to definition of a type in the current file with ido-mode (fast).
  • Go to definition of a member in the current type with ido-mode (likewise fast :)).
• Rename the current symbol and all references to it
• Solution manipulation
  • Add/remove the current file
  • Add/remove selected files in the dired directory editor
• Override selected superclass member
• Run a refactoring on the current position
  • Uses the refactorings from the NRefactory library, which is also used by the MonoDevelop and SharpDevelop IDEs
• Solution building
  • The user may choose whether they want to build in the emacs *compilation* buffer or at OmniSharp's end (non-asynchronous, that is, blocking)
  • Jump to errors like in normal *compilation* output
• Format the current buffer
  • Currently only one formatting style supported, easy to add more.
• Syntax checker for parse errors
  • Runs using the provided Flycheck checker in the background.
• OmniSharp server instance manipulation
  • Reload solution
  • Stop server

company-mode showing parameters and return values, and the selected function description in the minibuffer. As you can see, the completion works with non-trivial code.

company-mode also allows for yasnippet-like template completion of method parameters.

Pressing F1 with a candidate selected in the the company-mode popup shows a buffer with documentation.

popup.el with documentation. The documentation may be disabled if you need the screen space. There is an option to show documentation in a help buffer.

Ido allows for flexible matching of all text that the completions have. Each pressed character will narrow the list down to fewer options. It's also possible to do a cross search at any point with a new search term by pressing C-SPC.

This makes it really easy to e.g. narrow the list down to members that handle a specific type, such as bool.

This is a standard functionality in e.g. Visual Studio. The types are shown in the order they occur in the source file.

This too is standard in various IDEs. Using ido makes navigating fast and intuitive. The members too are shown in the order they occur in the source file.

Renaming suggests the current type as a basis.

When invoked, displays a list of possible override targets.

When a target is chosen, a stub member is inserted.

For now, this must be manually invoked. It can do different things depending on the symbol under point. In this picture it has been invoked on a method parameter.

Here is an example of an asynchronous build within Emacs. It works by getting the build command from the backend and executing that in the compilation buffer.

It is possible to check the current buffer for syntax errors using the flycheck library. This is done asynchronously, and errors are shown when found. Note that this is not a type checker, only syntax is currently checked.

This supports Emacs 24.3 and above at least. It has been tested on Ubuntu 12.04 (Precise), on Windows 7 and on OSX.

To install, use MELPA. After MELPA is installed, use

M-x package-install omnisharp RET

to install.

omnisharp-emacs depends on the external program curl for accessing the background OmniSharp server process. You need to ensure this is installed and can be found by Emacs.

To automatically load omnisharp-emacs when editing csharp files, add something like this to your csharp-mode-hook:

(add-hook 'csharp-mode-hook 'omnisharp-mode)

Start an OmniSharp server process on a solution, and you should have access to all of this program's functions. You probably need to create a custom configuration for accessing them in your normal coding sessions.

To enable company-mode autocompletion, omnisharp requires at least version 0.6.11 of company-mode to be installed. Then add the following to your dotemacs:

(eval-after-load 'company
  '(add-to-list 'company-backends 'company-omnisharp))

company-mode completion will only trigger when omnisharp-mode is active.

Pull requests welcome!