ASP.NET Core Identity - get current user
<p>To get the currently logged in user in MVC5, all we had to do was:</p>

<pre><code>using Microsoft.AspNet.Identity;
[Authorize]
public IHttpActionResult DoSomething() {
    string currentUserId = User.Identity.GetUserId();
}
</code></pre>

<p>Now, with ASP.NET Core I thought this should work, but it throws an error.</p>

<pre><code>using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Http;

private readonly UserManager&lt;ApplicationUser&gt; _userManager;
[HttpPost]
[Authorize]
public async Task&lt;IActionResult&gt; StartSession() {
    var curUser = await _userManager.GetUserAsync(HttpContext.User);
}
</code></pre>

<p>Any ideas?</p>

<p><strong>EDIT:</strong> Gerardo's response is on track but to get the actual "Id" of the user, this seems to work:</p>

<pre><code>ClaimsPrincipal currentUser = this.User;
var currentUserID = currentUser.FindFirst(ClaimTypes.NameIdentifier).Value;
</code></pre>