How can I trigger/load avisynth like media player classic or ffmpeg.exe does?

Question

I have an avs script say sample.avs If I drop this on media player classic or do open with OR

or I use the script with ffmpeg.exe it works.But if I simply type sample.avs on the command prompt the file opens in notepad.Can I write some code in C# to do something to trigger/load avisynth like the player or ffmpeg.exe do.

thanks.