What's the difference between context.Get() and its generic version?

Question

I'm trying to get familiar with OWIN and there are a lot of things that confuse me. For example, in partial startup.cs class I register context callback via

app.CreatePerOwinContext(ApplicationDbContext.Create);
app.CreatePerOwinContext<ApplicationUserManager>(ApplicationUserManager.Create);

What's the difference? Why do we need that generic method?

I can get that context like this:

context.Get<ApplicationDbContext>())
context.GetUserManager<ApplicationUserManager>()

What's the difference between the Get and GetUserManager methods? Why can't I just call context.Get for ApplicationUserManager?

What is `context`? dbContext, OWIN context, HttpContext? – jamesSampica Feb 18 '15 at 16:12 — jamesSampica, Feb 18 '15 at 16:12
Owin context, i thought it's obvious – Toddams Feb 18 '15 at 16:40 — Toddams, Feb 18 '15 at 16:40

jamesSampica · Accepted Answer · 2015-02-18T21:22:44.460

6

There is no difference between Get<UserManager> and GetUserManager<UserManager>

Here's the source code for both...

    /// <summary>
    ///     Retrieves an object from the OwinContext using a key based on the AssemblyQualified type name
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <param name="context"></param>
    /// <returns></returns>
    public static T Get<T>(this IOwinContext context)
    {
        if (context == null)
        {
            throw new ArgumentNullException("context");
        }
        return context.Get<T>(GetKey(typeof (T)));
    }

    /// <summary>
    ///     Get the user manager from the context
    /// </summary>
    /// <typeparam name="TManager"></typeparam>
    /// <param name="context"></param>
    /// <returns></returns>
    public static TManager GetUserManager<TManager>(this IOwinContext context)
    {
        if (context == null)
        {
            throw new ArgumentNullException("context");
        }
        return context.Get<TManager>();
    }

edited Feb 18 '15 at 21:22

answered Feb 18 '15 at 18:57

jamesSampica

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Doesn't answer the Q, *what's the difference between Get() and the generic version*. – Anders Abel Feb 18 '15 at 19:10
1

So if there is no difference, I can easily call context.Get() instead of context.GetUserManager? So why do we need a separate method for only getting a UserManager? – Toddams Feb 18 '15 at 21:37
Yes. You dont need a separate method and you can obviously interchange them. As for the reasoning for this I'm not sure. Could be something left over from an earlier version of Identity. – jamesSampica Feb 18 '15 at 22:09
@Shoe is `Get` not part of Owin? and `GetUserManager` is from Identity? I mean they are from different assemblies and used by different components? – trailmax Feb 18 '15 at 22:51
Thank you, finally I got it ;) – Toddams Feb 18 '15 at 23:29
2

@trailmax `Get(string)` is part of OWIN `Get()` and `GetUserManager()` are some owin extensions in the identity namespace. – jamesSampica Feb 19 '15 at 00:06
@Shoe in that case having 2 methods make sense. I'd include that in the answer as a reason behind having 2 similar methods. – trailmax Feb 19 '15 at 00:42
@trailmax The two `Get` methods make sense. I'm not sure why `GetUserManager` exists – jamesSampica Feb 19 '15 at 04:03

What's the difference between context.Get() and its generic version?

1 Answers1