asp.net identity get all roles of logged in user

Controller.User.Identity is a ClaimsIdentity. You can get a list of roles by inspecting the claims...

var roles = ((ClaimsIdentity)User.Identity).Claims
                .Where(c => c.Type == ClaimTypes.Role)
                .Select(c => c.Value);

--- update ---

Breaking it down a bit more...

using System.Security.Claims;

// ........

var userIdentity = (ClaimsIdentity)User.Identity;
var claims = userIdentity.Claims;
var roleClaimType = userIdentity.RoleClaimType;
var roles = claims.Where(c => c.Type == ClaimTypes.Role).ToList();

// or...
var roles = claims.Where(c => c.Type == roleClaimType).ToList();

Here's an extension method of the above solution.

    public static List<string> Roles(this ClaimsIdentity identity)
    {
        return identity.Claims
                       .Where(c => c.Type == ClaimTypes.Role)
                       .Select(c => c.Value)
                       .ToList();
    }