为什么C#TryParse不能处理NaN？

在读取一些旧的Fortran数据时,我有一些常用的方法可以使用默认值覆盖进行解析.有时,数据的NaN(非数字)应该有一个数值.我预计TryParse会看到字符串“NaN”并且无法解析.但是,TryParse成功解析并将NaN放入数值.这是预期的行为吗？如果这是预期的,我还应该寻找其他任何“陷阱”值吗？

public static double GetDoubleFromString(string s,double defaultOnFailure = 0)
    {
        //Must be here due to TryParse returning NaN to d and result is set to true below
        if (s.Contains("NaN"))
        {
            log.Warn(string.Format("String contained NaN,returning defaultOnFailure {0} string was {1}",defaultOnFailure,s));
            return defaultOnFailure;
        }

        var d = defaultOnFailure;
        if (!double.TryParse(s.Trim(),out d))
        {
            log.Warn(string.Format("Failed to parse double from string returning defaultOnFailure {0} string was {1}",s));
        }

        return d;
    }

UPDATE

我觉得应该提到,这只发生在double,long和int不返回NaN值.请参阅下面的示例代码,Common ….代码只是格式化的Console.WriteLine或停止执行控制台.请参阅下面的截图输出.

public static void NanTestMain()
    {
        Common.WriteBlankWithTitle("Test parse NaN");
        string s = "NaN";

        Common.WriteBlankWithTitle("NaN to Int");
        int i;
        var intSuccess = int.TryParse(s,out i);
        Console.WriteLine(string.Format("Int parse of {0} parse = {1}",i,intSuccess));

        Common.WriteBlankWithTitle("NaN to Double");
        double d;
        var doubleSuccess = double.TryParse(s,out d);
        Console.WriteLine(string.Format("Double parse of {0} parse = {1}",d,doubleSuccess));

        Common.WriteBlankWithTitle("NaN to Long");
        long l;
        var longSuccess = long.TryParse(s,out l);
        Console.WriteLine(string.Format("Long parse of {0} parse = {1}",l,longSuccess));

        Common.Pause();
    }