VB.NET Use API Messenger

I know how you can use the api in vb.net IM I wish simply by pressing a button sends a message to all my contacts. I apologize for开发者_开发技巧 my ignorance but I'm still learning, thanks

You don't mention what IM network you're talking about so I'm assuming you're talking about Live Messenger. If that's not the case, only the bit about Pidgin might still be relevant.

Unfortunately, my understanding is that nowdays there's no easy API for doing what you want, and you might have to write your own client to do this, here's a website that discusses the protocol:
http://www.hypothetic.org/docs/msn/index.php

You might also want to look at Pidgin since it supports Messenger and is open source:
http://www.pidgin.im/download/source/

There's a Live Messenger API, but I don't think that can be used to send a message from a standalone VB.Net desktop client since it seems more for writing Addins to the standard Live Messenger client, but here's the information about it in case I'm wrong:
http://msdn.microsoft.com/en-us/library/aa905675.aspx

If you're running XP or earlier you might be able to use the Windows Messenger SDK:
http://msdn.microsoft.com/en-us/library/ms630961%28v=VS.85%29.aspx