ASP.NET MVC4中的Active Directory字段-未处理的异常

Question

I need to implement a class which retrieves some fields from AD. I've followed the instruction from here: link . But I get an unhandled exception from line :

return (UserPrincipalExtended)FindByIdentityWithType(context, typeof(UserPrincipalExtended), identityValue)

My controller code looks like this:

using System.Threading.Tasks;
using System.Net;
using System.Data.Entity;
using System.DirectoryServices.AccountManagement;
(...)

public class HomeController : Controller
{
   private FormsEntities db = new FormsEntities();

   public async Task<ActionResult> Index()
   {          
        UserPrincipalExtended user = UserPrincipalExtended.FindByIdentity(
        new PrincipalContext(ContextType.Domain), User.Identity.Name);          

        var title = user.Title;        
        ViewBag.Message = title;

        return View();
   }

Should I add any additional configuration? In web.config for example? I'd like to mention that I successfully implement Windows authentication with AD login and password and the code.

string userName = HttpContext.User.Identity.Name.Split('\\')[1].ToString();

shows right user. Also I've tried to manipulate an object type [DirectoryObjectClass("user")] but without any result.

Answer 1

First of all, I would recommend putting your PrincipalContext into a using() { ... }? block to ensure proper disposal.

Also: whenever you call a method that goes into eg Active Directory (or a database, or calls a web service) - then you need to ensure that you're actually getting back something valid! Don't just blindly assume the call succeeded - maybe it did - maybe it didn't - check for success!

So I would write this index method like this:

public async Task<ActionResult> Index()
{          
    using (PrincipalContext ctx = new PrincipalContext(ContextType.Domain))
    {
        UserPrincipalExtended user = UserPrincipalExtended.FindByIdentity(ctx, User.Identity.Name);          

        // check FOR NULL ! 
        // Defensive programming 101 - ALWAYS check, NEVER just assume!
        if (user != null) 
        {
            var title = user.Title;        
            ViewBag.Message = title;
        }
        else 
        {
            // handle the case that NO user was found !
            ViewBag.Message = "(no user found)";
        }
    }

    return View();
}