C# development on a Raspberry Pi

October 30, 2015

Recently I’ve decided to try to set up a C# development environment on my Raspberry Pi 2 using Vim and OmniSharp. It has been a long process, so I wanted to document each of the problems I faced (and the solutions) here for the next time I try this.

The platform

I’m using Raspbian at the following version:

josh@raspberrypi ~ $ cat /etc/issue
Raspbian GNU/Linux 7 \n \l
josh@raspberrypi ~ $ cat /etc/debian_version

I have mono 3.2.8 installed, and I started off with the latest version of Vim available in a package for Raspbian (but we’ll see later that had to change).

The problems

I’ll go through each problem I had while I tried to set up an OmniSharp development environment with Vim.

Problem 1

OmniSharp requires Vim with Python support. After installing omnisharp-vim with Vundle I saw this error from Vim when I started it:

Error: OmniSharp requires Vim compiled with +python

Fix 1

I found that the vim-nox package is built with Python support, so I installed it.

Problem 2

When I opened a C# source file and tried to use omni-complete with <C-x><C-o> I saw this error:

Error detected while processing function OmniSharp#Complete:
line   14:
E117: Unknown function: pyeval
Error detected while processing function OmniSharp#Complete:
line   14:
E15: Invalid expression: pyeval('Completion().get_completions("s:column", "a:base")')

Fix 2

It turns out that the vim-nox package does not have a new enough version of Vim to use with OmniSharp. It is at version 7.3.547, but OmniSharp uses pyeval in Vim, which is at 7.3.569. So I installed Vim from source.

Problem 3

Vim needs to be compiled with Python support (see Problem 1 above).

Fix 3

I first had to install the python-dev package:

sudo apt-get install python-dev

Then I followed some good instructions to get Vim built correctly with Python support.

Problem 4

I next had to make Vim built from sources the default version used on my machine. It installed to /usr/local/bin.

Fix 4

I ran these commands:

sudo apt-get remove vim vim-runtime gvim
sudo update-alternatives --install /usr/bin/editor editor /usr/local/bin/vim 1
sudo update-alternatives --set editor /usr/local/bin/vim
sudo update-alternatives --install /usr/bin/vi vi /usr/local/bin/vim 1
sudo update-alternatives --set vi /usr/local/bin/vim

I also had to add /usr/local/bin to my PATH environment variable value.

Problem 5

Ready for everything to work now, I tried omni-complete again. When I did <C-x><C-o> and got this error:

-- Omni completion (^O^N^P) Pattern not found

It turns out the omnisharp-vim installation via Vundle did not actually build the Omnisharp.exe server.

Fix 5

I changed to the ~/.vim/bundle/omnisharp-vim/server directory and ran the xbuild command to build the OmniSharp.exe server.

Problem 6

I still did not have omni-complete! The OmniSharp server did start automatically from Vim because I was testing a .cs file that was not part of a project and solution file.

Fix 6

I was able to start the OmniSharp server manually. It starts automatically if I open Vim with a .cs file that is in project and a solution.

Problem 7

I attempted to set up grunt-init (as recommended on the omnisharp-vim site). I first tried to install the node and npm packages manually.

sudo apt-get install node
sudo apt-get install npm

But that does not work, as the npm package is too old.

Fix 7

So I then followed these instructions to get a working npm system. Then I could install grunt.

sudo apt-get purge nodejs npm
curl -sL https://deb.nodesource.com/setup | sudo bash -
sudo apt-get install nodejs
sudo npm install -g grunt-init


After these seven problems were solved, I was able to get omni-complete with C# working in Vim on my Raspberry Pi 2. Now to write some code!

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