public async Task <ActionResult> UpdateRole(string id)
        {
            IdentityRole role = await this.roleManager.FindByIdAsync(id);

            if (role is null)
            {
            }
            AdministrationEditRoleViewModel model = new AdministrationEditRoleViewModel()
            {
                Id       = role.Id,
                RoleName = role.Name,
                Users    = new List <string>()
            };

            foreach (var item in _userManager.Users)
            {
                if (await _userManager.IsInRoleAsync(item, role.Name))
                {
                    model.Users.Add(item.Email);
                }
            }
            return(View(model));
        }
        public async Task <ActionResult> UpdateRole(AdministrationEditRoleViewModel model)
        {
            if (ModelState.IsValid)
            {
                IdentityRole role = await this.roleManager.FindByIdAsync(model.Id);

                if (role is null)
                {
                }
                else
                {
                    role.Name = model.RoleName;
                    IdentityResult result = await roleManager.UpdateAsync(role);

                    if (result.Succeeded)
                    {
                        return(RedirectToAction(nameof(ListRole)));
                    }
                }
            }


            return(View(model));
        }