How to solve Json deserilization problem, Type 'System.String' is not supported for deserialization of an array?

The property is set to string type, but the json data is return a string array..

ASP.NET MVC fiddle, like jsfiddle, for the people don't like Visual Studio

http://dotnetfiddle.net/CsMvc

C# Safe Navigation Operator: ?.

http://blogs.msdn.com/b/jerrynixon/archive/2014/02/26/at-last-c-is-getting-sometimes-called-the-safe-navigation-operator.aspx

var g1 = parent.child.child.child;
Problem happens if any child is null.

New operator solves this problem
var g1 = parent?.child?.child?.child; 
if (g1 != null) // TODO

How to solve problem: 'xEntities': type used in a using statement must be implicitly convertible to 'System.IDisposable' when use using block to open Entity Framework data context?

Need to add EntityFramework.dll reference into your project file.

What is Open ID and its workflow?

OpenID allows you to use an existing account to sign in to multiple websites, without needing to create new passwords.
From:  http://openid.net/get-an-openid/what-is-openid/

OpenID 2.0 interaction sequence from Google
https://developers.google.com/accounts/docs/OpenID?csw=1#Interaction