Where are tutorials for DotNetOpenAuth and how to solve compile error in its samples

I know stackoverflow uses OpenID authentication. I want to try and use this as well. I am using asp.net mvc 2.0 with C#.

I found this

http://www.dotnetopenauth.net/

and I am wondering if this is what was used for stackoverflow.

Also any tut开发者_如何学Pythonorials would be nice as well.

Edit

I am trying to load up some sample projects but when I build it in VS2010 I get

Error   6   'System.Diagnostics.Contracts.ContractInvariantMethodAttribute' is inaccessible due to its protection level C:\Users\chobo2\Downloads\DotNetOpenAuth-3.4.6.10357\DotNetOpenAuth-3.4.6.10357\Samples\OpenIdOfflineProvider\TextBoxTextWriter.cs  73  4   OpenIdOfflineProvider
Error   7   The type or namespace name 'ContractInvariantMethod' could not be found (are you missing a using directive or an assembly reference?)   C:\Users\chobo2\Downloads\DotNetOpenAuth-3.4.6.10357\DotNetOpenAuth-3.4.6.10357\Samples\OpenIdOfflineProvider\TextBoxTextWriter.cs  73  4   OpenIdOfflineProvider

Yes, it is the library SO uses. See this blog post from Jeff:

we have an excellent dialog with Andrew Arnott, the primary author of the open source DotNetOpenAuth library we use.

The download includes samples.

I have just found this tutorial which is useful.

Edit: This one also looks worth a read.

And I also found this example useful.

Far too many things to comment, as suggested by Alex Angas. Best to just install the dependency, it's not included by default with .NET.

Code Contracts: http://research.microsoft.com/en-us/projects/contracts/

DotNetOpenAuth is a trustworthy choice.

To fix the build errors, comment out all references to Contract(...) in the code. They're only there to help the developers ensure code correctness and don't provide any functionality.