I need to compare dates in two separate list. Each list is constructed of MyFile Objects. That is a class that I created in order to have specific information about a file such as name, dateModified, extension, etc. The only problem is that a lot of MyFiles objects in my second list (got those from external hard drive) do not have the dateTime stamp (LastWriteTime) till the millisecond. I believe that is the reason why my comparison is not working. For example here is an example of how my comparison is failing: "Why does c# thinks the dates are not equal?"
a and b are MyFile objects and MyFile class contains a property ticks and that is equal to the file.LastWriteTime.Ticks they are not used in the program I just included them for debugging purposes. So after debugging several times I realized that the last 7 digits represent the milliseconds of a file. As a result my ticks property in MyFile now contains 11 significant figures instead than 18 ( note 18-11 = 7). The problem with this is that when I compare the ticks I get strange results when I try to update the ticks property by dividing by 10000000 and then multyplying by 10000000. Since my ticks propery is a long int it will lose the last 7 digits when I divide. I get less 'errors'. But there is some other times when I get something like this:
在这里我们可以看到日期至少在第二个之前是相同的。为什么 c# 认为它不是同一个日期？我必须创建自己的“Ticks”函数吗？我知道我将 dateTime 转换为字符串然后进行比较，但我想知道对象 a.dateModified 是否存在 比对象 b.dateModified 新
尝试与特定精度进行比较：
DateTime a, b;
// fill a and b with the values you need
if (Math.Abs((a-b).TotalSeconds) < 1)
Console.WriteLine("File doesn't need to be copied");
else
Console.WriteLine("File needs to be copied");