I just tried to build a asp.net web form application with open ID authentication through Azure AD.
I followed the steps http://www.cloudidentity.com/blog/2014/07/24/protecting-an-asp-net-webforms-app-with-openid-connect-and-azure-ad/.
I now get the error at the line:
protected void Page_Load()
{
var manager = Context.GetOwinContext().GetUserManager<ApplicationUserManager>();
HasPhoneNumber = string.IsNullOrEmpty(manager.GetPhoneNumber(User.Identity.GetUserId()));
In the HasPhoneNumber line I just get an exception:
An exception of type 'System.ArgumentNullException' occurred in Microsoft.AspNet.Identity.Core.dll but was not handled in user code
Additional information: Value cannot be null.
Why do I get the error?
Also, if I could get an overview/resource of what a web form is and how it works, that would be great. Thanks.