When changing the id type from a string to int, how to get the identifier of the current signed-up user in the web API?

Question

Using the ASP.NET Web API with ASP.NET Identity 1.0, you can use this extension method to retrieve the current signed-in user:

var id = Microsoft.AspNet.Identity.IdentityExtensions.GetUserId(User.Identity); 

But in ASP.NET identity 2.0 alpha, you can override the type for the identifier field . The example provided by Microsoft shows that this field is int. But this extension method seems hard-coded to return a string even in alpha:

http://msdn.microsoft.com/en-us/library/microsoft.aspnet.identity.identityextensions.getuserid(v=vs.111).aspx

How can you get the identifier (int) of the current user as part of the web API controller when using ASP.NET Identity 2.0 alpha?

Answer 1

You must manually perform the conversion manually, because the claims are internal strings. We could provide some kind of general extension, for example User.Identity.GetUserId, which is trying to convert from a string → T, and this is what we are looking at in future versions.

Answer 2

I ended up using:

 public static class IdentityExtensions { public static T GetUserId<T>(this IIdentity identity) where T : IConvertible { return (T)Convert.ChangeType(identity.GetUserId(), typeof(T)); } } 

and calling it like: GetUserId<int>()