| Description |
The Subtract method does two very different things :
1. Returns a TimeSpan value as the difference between the current DateTime value and the Value DateTime value. The TimeSpan value contains a day and time value - the value is a total elapsed time, not a point in time.
2. Returns a DateTime value. You provide a day/time span, which gets subtracted from the current DateTime value to give the return value.
|
|
| Microsoft MSDN Links |
System
System.DateTime
|
|
|
| A simple example illustrating both methods |
program Project1;
{$APPTYPE CONSOLE}
var
dateTime1, dateTime2 : DateTime;
timeSpan1 : TimeSpan;
begin
dateTime1 := DateTime.Create(2004, 6, 20); // 00:00:00 on 20 June 2004
dateTime2 := DateTime.Create(2004, 7, 11); // 00:00:00 on 11 July 2004
Console.WriteLine('dateTime1 = {0:F}', dateTime1);
Console.WriteLine('dateTime2 = {0:F}', dateTime2);
Console.WriteLine;
Console.WriteLine('Subtracting dateTime2 from dateTime1');
Console.WriteLine;
timeSpan1 := dateTime2.Subtract(dateTime1);
Console.WriteLine('Gives time span = {0:F}', timeSpan1);
Console.WriteLine;
Console.WriteLine('Subtracting this time span from dateTime1');
Console.WriteLine;
dateTime1 := dateTime1.Subtract(timeSpan1);
Console.WriteLine('dateTime1 now = {0:F}', dateTime1);
Console.ReadLine;
end.
| | Show full unit code | dateTime1 = 20 June 2004 00:00:00
dateTime2 = 11 July 2004 00:00:00
Subtracting dateTime2 from dateTime1
Gives time span = 21.00:00:00
Subtracting this time span from dateTime1
dateTime1 now = 30 May 2004 00:00:00
|
| |
|
|
|