很简单的问题 delphi的datetime类型是什么 如何计算2个datetime的时间差
2个datetime的时间差如何转换成float
[解决办法]
TDateTime represents a date-and-time value in the Delphi language.
Unit
System
Delphi syntax:
type TDateTime = type Double;
Description
Most CLX objects represent date and time values using a TDateTime value. In Delphi, TDateTime is a type that maps to a Double. In C++, the TDateTime class corresponds to the Delphi TDateTime type.
The integral part of a Delphi TDateTime value is the number of days that have passed since 12/30/1899. The fractional part of the TDateTime value is fraction of a 24 hour day that has elapsed.
Following are some examples of TDateTime values and their corresponding dates and times:
012/30/1899 12:00 am
2.751/1/1900 6:00 pm
-1.2512/29/1899 6:00 am
350651/1/1996 12:00 am
To find the fractional number of days between two dates, simply subtract the two values, unless one of the TDateTime values is negative. Similarly, to increment a date and time value by a certain fractional number of days, add the fractional number to the date and time value if the TDateTime value is positive.
When working with negative TDateTime values, computations must handle time portion separately. The fractional part reflects the fraction of a 24-hour day without regard to the sign of the TDateTime value. For example, 6:00 am on 12/29/1899 is -1.25, not -1 + 0.25, which would be -0.75. There are no TDateTime values between -1 and 0.
There are no TDateTime values between -1 and 0.
