UserModel.cs

 public class UserModel
    {
        public int usr_Id { get; set; }

        [Display(Name = "Username")]
        [Required(ErrorMessage="Username is required")]
        [RegularExpression(@"^[a-zA-Z0-9]+$", ErrorMessage = "user name must be combination of letters and numbers only.")]
        public string username { get; set; }

        [Display(Name = "Email")]
        [Required(ErrorMessage = "Email is required")]
        [EmailAddress(ErrorMessage="Invalid email address")]
        public string email { get; set; }

        [Display(Name = "Password")]
        [Required(ErrorMessage = "Password is required")]
        public string password { get; set; }

        [Display(Name = "Confirm Password")]
        [Required(ErrorMessage = "Confirmation of password is required")]
        [Compare("password", ErrorMessage="Passwords do not match")]
        public string confirmPassword { get; set; }

    }