public class RegisterModel : IValidatableObject

{

    public int RegisterCount{get;set;}

    public int Qutoa{get;set;}

    //实现IValidatableObject接口方法，实现自定义验证

    public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)

    {

        var results = new List<ValidationResult>();

        if (RegisterCount > Quota)

        {

            results.Add(new ValidationResult("报名人数已经超过名额限制", new string[] { "RegisterCount" }));

        }

        if (RegisterCount>3)

        {

            results.Add(new ValidationResult("单次最多报名三位学员", new string[] { "RegisterCount" }));

        }

        return results;

    }

}