Screen Sharing in c#

Question

Hello i would like to make software for screen sharing (something like team viewer but without desktop remote , only screen share) in c#

is there any finished project like this ? 

Please if you can help me , be usefull :)

This is one of source codes i ve found : 

http://www.codeproject.com/Articles/371955/Motion-JPEG-Streaming-Server

About this :  it works good , but seems like it cant work online , only works on same IP connected computers 
maybe you know how to make it works online ??

http://www.c-sharpcorner.com/uploadfile/ulricht/how-to-create-a-simple-screen-sharing-application-in-C-Sharp/

This one also works , but the other computer user cant see my screen , only i can see his 

Can anyone help ?