MVC模型范围验证器？

Question

我想验证日期时间,我的代码是:

    [Range(typeof(DateTime), 
     DateTime.Now.AddYears(-65).ToShortDateString(), 
     DateTime.Now.AddYears(-18).ToShortDateString(),
     ErrorMessage = "Value for {0} must be between {1} and {2}")]
    public DateTime Birthday { get; set; }

但我得到错误:

An attribute argument must be a constant expression, typeof expression or array creation expression of an attribute parameter type

请帮我？

Answer 1

这意味着Range属性的值无法在以后确定,必须在编译时确定.DateTime.Now不是常量,它会根据代码运行的时间而变化.

你想要的是一个自定义DataAnnotation验证器.以下是如何构建一个的示例:

如何创建自定义数据注释验证器

将您的日期验证逻辑放在IsValid()中

这是一个实现.我也使用DateTime.Subtract()而不是负数年.

public class DateRangeAttribute : ValidationAttribute
{
    public int FirstDateYears { get; set; }
    public int SecondDateYears { get; set; }

    public DateRangeAttribute()
    {
        FirstDateYears = 65;
        SecondDateYears = 18;
    }

    public override bool IsValid(object value)
    {
        DateTime date = DateTime.Parse(value); // assuming it's in a parsable string format

        if (date >= DateTime.Now.AddYears(-FirstDateYears)) && date <= DateTime.Now.AddYears(-SecondDateYears)))
        {
            return true;
        }

        return false;
}

}

用法是:

[DateRange(ErrorMessage = "Must be between 18 and 65 years ago")]
public DateTime Birthday { get; set; }

它也是通用的,因此您可以指定多年的新范围值.

[DateRange(FirstDateYears = 20, SecondDateYears = 10, ErrorMessage = "Must be between 10 and 20 years ago")]
public DateTime Birthday { get; set; }