Well, from this question, I have got three points:
1, filewatcher.exe is developed by VS2012 - Windows Service(C#) project, this kind of .exe cannot be run by mono on Ubuntu, maybe windows service's special configuration can only be install as windows service. However, normal C# executable file (e.g: Windows Forms Application's exe file) can be run by mono on Ubuntu.
2, Although mono runtime cannot be set as the default application for filewatcher.exe, we can use
mono filewatcher.exe
to run it.
So, we can create a script like this - assume the script file name is filewatcherservice:
#! /bin/bash
mono /home/user/filewatcher.exe
and then, use the following command:
sudo chmod +x filewatcherservice
to make it an executable file
then, copy this file to /etc/init.d directory
finally,install the filewatcherservice as a service
sudo update-rc.d filewatcherservice defaults
3, Use the following command(maybe you need to install it before use it)
sudo sysv-rc-conf
to start the service.
Done!
Thanks everybody for your help.