I just took a quick look at SlimDX. Here are two blogs about on using SlimDX in C#
Full Xbox 360 Gamepad Support In C#, Without XNA
By: Renaud Bédard
XBox controller with C#
By: Ian Morton
This snippet was taken from SlimDX’s website, http://slimdx.org/.
What is SlimDX?
SlimDX is a free open source framework that enables developers to easily build DirectX applications using .NET technologies such as C#, VB.NET, and IronPython. It is designed to be an efficient, simple, and lean wrapper that fully encompasses all of Microsoft’s gaming and multimedia technologies and exposes them to managed code. All of the code is under the MIT/X11 license, and all content is under the Creative Commons Attribution-Share Alike license. Our latest release is March 2011, and can be found for users and developers on the Download page.
All development is based in our Google Code homepage. You can use that site to report bugs (using our issues page), as well as download a complete copy of the source code. If you have questions to ask, or otherwise wish to discuss SlimDX, we ask that you use the DirectX forum on GameDev.Net. This is the only forum on which the developers are active; we do not use any other forums or mailing lists. Please prefix your thread subject with [SlimDX] if the question is reasonably specific to SlimDX. If it isn’t, feel free to include or exclude the prefix as you like. You can also try and get a hold of us on IRC, in the #graphicsdev channel on AfterNET.