在VBA Excel中处理时间时得到错误的值

Question

I'm trying to do some calculations on my excel sheet where I'm using macros , i'm dealing with time values.

 h2 = rg.Cells(i, 5) 'time value
 h1 = rg.Cells(i, 4) 'time value
 h3 = (TimeValue("23:59") - h1) + (h2 - TimeValue("23:59"))

the problem is for instance when h1="20:00" and h2="07:55" h3 should be 11:55 but it gives 12:05

BTW H1 is entrance time and H2 is time out so h2 is in the next day and i'm trying to calculate the deference of time.

regards

Answer 1

Because H2, as you point out, is a day after H1, you need to factor that in to your calculation.

So to calculate the difference between H1 and H2, 24 hours should be added to H2 first.

  h2  +  1dy
07:55 + 24:00 = 31:55

                  v
                         -h1
                31:55 - 20:00 = 11:55

A single day presented as time is 1 - as time is measured as a decimal fraction of a day.

So among many other ways of doing it, to get the above, your formula should be:

h3 = (h2 + 1) - h1

Answer 2

In fact the correct answer is minus 11:05:00 but Excel doesn't handle negative time. Adding one day to minus 11:05::00 equals positive 12:05:00.