参考介绍 http://www.monodevelop.com/download/linux/

首先，Add the Mono Project GPG signing key 

sudo apt-key adv --keyserver pgp.mit.edu --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF

其次，Add the package repository 

　　echo "deb http://download.mono-project.com/repo/debian wheezy main" | sudo tee /etc/apt/sources.list.d/mono-xamarin.list

然后开始安装

　　sudo apt-get install monodevelop
　　sudo apt-get install monodevelop-nunit
　　sudo apt-get install monodevelop-versioncontrol
　　sudo apt-get install monodevelop-database

如何在Ubuntu下安装 monodevelop