Remove User from Roles in ASP.NET Identity 2.x

Question

How can I remove User from Roles in ASP.NET Identity 2.x ? about adding role to user there is no problem but when I want to remove a role from a user I cannot.It should be mentioned that there is no exception or error!

//POST: Admin/User/Edit/5
    [AcceptVerbs(HttpVerbs.Post)]
    [ValidateAntiForgeryToken]
    public async Task<ActionResult> Edit([Bind(Prefix = "")]UserViewModel userViewModel, List<int> availableRoles)
    {
        if (ModelState.IsValid)
        {
            List<int> newListOfRolesIDs = availableRoles;
            List<int> oldListOfRolesIDs = UserBLL.Instance.GetRolesIDs(userViewModel.Id);
            List<int> deletedList;
            List<int> addedList;
            var haschanged = oldListOfRolesIDs.ChangeTracking(newListOfRolesIDs, out deletedList, out addedList);
            using (new EFUnitOfWorkFactory().Create())
            {
                if (haschanged)
                {
                    UserBLL.Instance.InsertRoles(addedList, userViewModel.Id);
                    UserBLL.Instance.DeleteRoles(deletedList, userViewModel.Id);
                }
                await UserBLL.Instance.UpdateAsync(userViewModel);
            }
            //ArticleBLL.Instance.UpdatePartial(articleViewModel,  m => m.Title);
            return RedirectToAction("Edit");
        }
        return View(userViewModel);
    }

Delete Role method:

public void DeleteRoles(List<int> deleteList, int? userId)
    {
        if (userId != null)
        {
            User user = UserManager.FindByIdAsync(userId.Value).Result;
            foreach (var i in deleteList)
            {
                user.Roles.Remove(new UserRole { RoleId = i, UserId = user.Id }); // What's the problem?!
            }
        }
    }

Insert Role method:

public void InsertRoles(List<int> insertList, int? userId)
    {
        if (userId != null)
        {
            User user = UserManager.FindByIdAsync(userId.Value).Result;
            foreach (var i in insertList)
            {
                user.Roles.Add(new UserRole { RoleId = i, UserId = user.Id });
            }
        }
    }

Answer 1

What you are looking for is the RemoveFromRoleAsync method. An example would look similar to the following:

public async Task DeleteRolesAsync(List<string> deleteList, int? userId)
{
    if (userId != null)
    {
        foreach (var roleName in deleteList)
        {
            IdentityResult deletionResult = await UserManager.RemoveFromRoleAsync(userId, roleName);
        }
    }
}

If you already have the ID of the user, there's no need to get the user again (only if you want to make sure that the user really exists; then you have to wrap your foreach with an if-statement). The deletion methods needs the name of the role, instead of the ID, to delete the user from the role. You can use the result of the operation (in my example stored in deletionResult) to make sure that the operation was successful. Remember that the name of the user manager (in my example UserManager) can vary depending on your implementation.