protected void SubmitButton_Click(object sender, EventArgs e) { var userRole = new IdentityUserRole(); userRole.RoleId = this.context.Roles.FirstOrDefault(x => x.Name == "user").Id; var targetUser = this.context.Users.Where(u => u.UserName == this.UsersDropdown.SelectedItem.Text).First(); targetUser.Roles.Clear(); targetUser.Roles.Add(userRole); this.context.SaveChanges(); Notifier.AddInfoMessage(string.Format("{0}, is regular user now!", targetUser.UserName)); }