asp.net – 自定义验证属性不呈现客户端验证属性

根据我在Github上搜索源代码看到的内容,我不需要做任何其他事情.我在这里错过了什么？

[AttributeUsage(AttributeTargets.Property,AllowMultiple = false,Inherited = true)]
public class PastDateOnlyAttribute : ValidationAttribute,IClientModelValidator
{
    private const string DefaultErrorMessage = "Date must be earlier than today.";

    public override string FormatErrorMessage(string name)
    {
        return DefaultErrorMessage;
    }

    public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ClientModelValidationContext context)
    {
        var rule = new ModelClientValidationPastDateOnlyRule(FormatErrorMessage(context.ModelMetadata.GetDisplayName()));

        return new[] { rule };
    }

    protected override ValidationResult IsValid(object value,ValidationContext validationContext)
    {
        if (value != null)
        {
            var now = DateTime.Now.Date;
            var dte = (DateTime)value;

            if (now <= dte) {
                return new ValidationResult(FormatErrorMessage(validationContext.DisplayName));
            }
        }

        return ValidationResult.Success;
    }
}

public class ModelClientValidationPastDateOnlyRule : ModelClientValidationRule
{
    private const string PastOnlyValidateType = "pastdateonly";
    private const string MaxDate = "maxdate";

    public ModelClientValidationPastDateOnlyRule(
            string errorMessage)
        : base(validationType: PastOnlyValidateType,errorMessage: errorMessage)
    {   
        ValidationParameters.Add(MaxDate,DateTime.Now.Date);
    }
}

(省略JavaScript代码,因为它不相关.)