模型
public class UserModel
{
[Required]
[StringLength(6, MinimumLength = 3)]
[RegularExpression(@"(\S)+", ErrorMessage = "White space is not allowed")]
public string UserName { get; set; }
[Required]
[StringLength(8, MinimumLength = 3)]
public string FirstName { get; set; }
[Required]
[StringLength(9, MinimumLength = 2)]
public string LastName { get; set; }
[Required]
public string City { get; set; }
}