C# DateTime.CompareTo 实际返回什么整数？
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What integer does DateTime.CompareTo actually return?
提问by philkark
I have been looking for an answer for some time now, but nowhere could I actually find it.
一段时间以来，我一直在寻找答案，但实际上无处可寻。
I was especially looking at this page. There it says that the CompareTomethod returns an integer indicating if it is earlier, the same, or later. I understand the use of it and I understand that for earlier times the integer is negative, for the same it is 0 etc.
我特别在看这个页面。它说该CompareTo方法返回一个整数，指示它是更早、相同还是更晚。我了解它的使用，并且我了解早期的整数是负数，同样它是 0 等。
But what is this integer? Does it return the difference in seconds, milliseconds, ticks, or maybe nothing at all? I hope you can help me with this and if anyone can find another post with this question, please tell me. I am honestly quite surprised that I couldn't find a question on this topic straight away...
但这个整数是什么？它是否返回以秒、毫秒、滴答为单位的差异，或者什么都不返回？我希望你能帮我解决这个问题，如果有人能找到关于这个问题的另一篇文章，请告诉我。老实说，我很惊讶我无法立即找到关于这个主题的问题......
采纳答案by kabaros
The documentation is actually in the IComparableinterface page (that DateTime implements): http://msdn.microsoft.com/en-us/library/system.icomparable.aspx
该文档实际上在IComparable接口页面（DateTime 实现）中：http: //msdn.microsoft.com/en-us/library/system.icomparable.aspx
The implementation of the CompareTo(Object) method must return an Int32 that has one of three values, as shown in the following table.
Less than zero:The current instance precedes the object specified by the CompareTo method in the sort order.
Zero:This current instance occurs in the same position in the sort order as the object specified by the CompareTo method.
Greater than zero:This current instance follows the object specified by the CompareTo method in the sort order.
CompareTo(Object) 方法的实现必须返回一个具有三个值之一的 Int32，如下表所示。
小于零：当前实例在排序顺序中位于 CompareTo 方法指定的对象之前。
零：此当前实例出现在与 CompareTo 方法指定的对象在排序顺序中相同的位置。
大于零：此当前实例在排序顺序中跟随由 CompareTo 方法指定的对象。
回答by Marc Gravell
It is an implementation detail that you should never need to know and can change at any time. The only 3 categories are:
这是一个您永远不需要知道并且可以随时更改的实现细节。仅有的3类是：
- negative
- zero
- positive
- 消极的
- 零
- 积极的
If you find yourself using anything more than that, then something is wrong.
如果你发现自己使用的东西不止这些，那就有问题了。
回答by Rotem
As far as I can tell the number is always -1, 0, or 1.
据我所知，该数字始终为 -1、0 或 1。
回答by Euphoric
It is implementation of IComparable.CompareTo. This means it will return 0 if equal, positive integer if bigger and negative integer when smaller.
它是IComparable.CompareTo 的实现。这意味着如果相等，则返回 0，如果较大则返回正整数，较小时返回负整数。
回答by RvdK
There is nothing specified, according to MSDN:
根据 MSDN，没有指定任何内容：
if (result < 0)
relationship = "is earlier than";
else if (result == 0)
relationship = "is the same time as";
else
relationship = "is later than";
If you want to compare days between 2 DateTimes you should be looking for something like this:
如果你想比较 2 个 DateTimes 之间的天数，你应该寻找这样的东西：
if ((expiryDate - DateTime.Now).Days < 30)
回答by John
You can choose the specific units to compare with TimeSpan
您可以选择要与 TimeSpan 进行比较的特定单位
DateTime local_time = DateTime.Now; //current time
DateTime local_time = DateTime.Now; //current time
DateTime remote_time = DateTime.Now.AddMinutes(-2); //two minutes delayed
DateTime remote_time = DateTime.Now.AddMinutes(-2); //two minutes delayed
TimeSpan time_difference = (local_time - remote_time);
TimeSpan time_difference = (local_time - remote_time);
if (time_difference.Minutes <= 5) //compare specific units desired
if (time_difference.Minutes <= 5) //compare specific units desired
{
{
bool within_tollerance = true;
bool within_tollerance = true;
}
}
