c# - 在 DataAnnotations 中使用当前年份作为范围验证

Question

[Range(1900, DateTime.Now.Year, ErrorMessage = "Please enter a valid year")]

这行不通。对于“DateTime.Now.Year”，它告诉我

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

Answer 1

您可以创建自己的 RangeUntilCurrentYearAttribute 来扩展 RangeAttribute。

[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field, AllowMultiple = false)]
public class RangeUntilCurrentYearAttribute : RangeAttribute
{
    public RangeUntilCurrentYearAttribute(int minimum) : base(minimum, DateTime.Now.Year)
    {
    }
}

然后像这样使用它:

public class Foo
{
    [RangeUntilCurrentYear(1900, ErrorMessage = "Please enter a valid year")]
    public int Year { get; set; }
}