MVC IValidatable方法仅在预定义属性之后执行

Question

我有这样定义的模型：

public class AdvisoryViewModel : IValidatableObject
{
    [Display(Name = "Start Date")]
    [DisplayFormat(DataFormatString = "{0:d}", ApplyFormatInEditMode = true, ConvertEmptyStringToNull = true)]
    public DateTime? StartDate { get; set; }

    [Display(Name = "End Date")]
    [DisplayFormat(DataFormatString = "{0:d}", ApplyFormatInEditMode = true, ConvertEmptyStringToNull = true)]
    public DateTime? EndDate { get; set; }

    [Display(Name = "Instructions")]
    [Required(ErrorMessage = "Instructions are required")]
    [MaxLength(500, ErrorMessage = "Instructions cannot be longer than 500 characters.")]
    public string Instruction { get; set; }

    IEnumerable<ValidationResult> IValidatableObject.Validate(ValidationContext validationContext)
    {
        List<ValidationResult> results = new List<ValidationResult>();
        if (StartDate.HasValue &&
            EndDate.HasValue &&
            StartDate.Value > EndDate.Value)
        {
            ValidationResult result = new ValidationResult("Start date must be after end date.");
            results.Add(result);
        }
        return results;
    }

我正在验证如下：

        var validationResults = new List<ValidationResult>();

        if (!Validator.TryValidateObject(advisoryViewModel, new ValidationContext(advisoryViewModel), validationResults,  true))
        {
            return Json(new { success = false, message = string.Join("; ", validationResults.Select(r => r.ErrorMessage)) });
        }

验证会发生什么，它首先只调用＆＃34;必需＆＃34;属性 - 例如，如果开始日期晚于结束日期且指令为空，则仅返回指令不能为空的消息。一旦它们不为null，它将返回开始/结束日期错误消息。

有没有办法让它预先进行所有验证而不是两次尝试？

另外，有没有办法将开始/结束验证添加到客户端结果？