Asp.NET Identity Core IsInRole InvalidOperationException: Sequence contains more than one element

Question

I have this code:

...
var _context = new MyDbContext();     
var _userManager = new UserManager<User>(new UserStore<User>(_context));
...
public bool IsInRole(string userId, string roleName)
{
    return _userManager.IsInRole(userId, roleName); //InvalidOperationException
}

Throws this exception:

An exception of type 'System.InvalidOperationException' occurred in mscorlib.dll but was not handled in user code

Additional information: Sequence contains more than one element

Visual Studio 2015

.NET 4.5

Microsoft AspNet Identity Core 2.2.1

Entity Framework 6

There were duplicated rows in my IdentityRoles table. Removing these solved the problem. Thank you for your help! — Péter Aradi
– Péter Aradi, Commented Jul 14, 2017 at 12:59
No problem, but next time wait for the person who suggested the possibility to add the answer so they can get the recognition :) — DavidG
– DavidG, Commented Jul 14, 2017 at 13:02

Péter Aradi · Accepted Answer · 2017-07-14 12:57:11Z

2

There are duplicated names in the IdentityRoles table:

SELECT *
FROM [dbo].[IdentityRoles]

Deleting the unnecessary rows solved the problem.

answered Jul 14, 2017 at 12:57

Péter Aradi

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1 Comment

CodeNotFound Over a year ago

Something went wrong in your database. Make sure that Name column has a UNIQUE CONSTRAINT

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