Time Values in VB.net - 500 points to Help me solve this !!!
Hello Experts,
This project has been a particular pain to me, I have asked a question here at EE in the past
using VB6 and got some resovlve, but I think it could go better.... my points offering should reflect this
now using VB.NET 2003
' my project is an environment simulator...which "controls" the amount of daylight in an environment
' what I want is for the user to be able to define "daystart" time and "nightstart" times
' as regular AM/PM values....... ie. daystart time = 8:35 AM nightstart = 10:17 PM into textboxes
' or DomainUpDownCOntrols.
' then based on those values, determine the length of "daytime" and "nighttime"
' daytime = time from daystart to nightstart
' nighttime = time from nightstart to daystart
' nighttime + daytime should equal 24 hours
' my goal is to then express this as a ratio, i.e 12/12, 18/6, 23/1 etc.
' and also preferably as 5.43/18.57 representing hours/minutes of the day/night ratio
' ( I do not care about seconds )
' after I have this part working I will set some boolean vars that specify
'If "Day" = "True" Then Night = "False"
This project has been a particular pain to me, I have asked a question here at EE in the past
using VB6 and got some resovlve, but I think it could go better.... my points offering should reflect this
now using VB.NET 2003
' my project is an environment simulator...which "controls" the amount of daylight in an environment
' what I want is for the user to be able to define "daystart" time and "nightstart" times
' as regular AM/PM values....... ie. daystart time = 8:35 AM nightstart = 10:17 PM into textboxes
' or DomainUpDownCOntrols.
' then based on those values, determine the length of "daytime" and "nighttime"
' daytime = time from daystart to nightstart
' nighttime = time from nightstart to daystart
' nighttime + daytime should equal 24 hours
' my goal is to then express this as a ratio, i.e 12/12, 18/6, 23/1 etc.
' and also preferably as 5.43/18.57 representing hours/minutes of the day/night ratio
' ( I do not care about seconds )
' after I have this part working I will set some boolean vars that specify
'If "Day" = "True" Then Night = "False"
ASKER CERTIFIED SOLUTION
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The magic behind smoees code is the TimeSpan() class. First you convert your two times to DateTime() instances. smoee has used CType(), but you could also use DateTime.Parse().
When you subtract two DateTime instances with the DateTime.Subtract() method you get a TimeSpan instance back that represents the amount of time between the two DateTimes. You can get the WHOLE number of Days, Hours, Minutes, Seconds, Milliseconds and even Ticks that the TimeSpan represents by using the Properties with those same names. You can also get the TotalHours, TotalMinutes, etc. that it represents. So if you had a TimeSpan that represented 2 1/2 hours you would get 2.5 from the TotalHours property but 2 and 30 from the Hours and Minutes properties respectively.
See here for more info:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemtimespanclasstopic.asp
When you subtract two DateTime instances with the DateTime.Subtract() method you get a TimeSpan instance back that represents the amount of time between the two DateTimes. You can get the WHOLE number of Days, Hours, Minutes, Seconds, Milliseconds and even Ticks that the TimeSpan represents by using the Properties with those same names. You can also get the TotalHours, TotalMinutes, etc. that it represents. So if you had a TimeSpan that represented 2 1/2 hours you would get 2.5 from the TotalHours property but 2 and 30 from the Hours and Minutes properties respectively.
See here for more info:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemtimespanclasstopic.asp
ASKER
Thanks for this code it does exactly as I have asked...... can I add one small question reagrding error trapping on this..... if someone enters an AM date for the start and a PM for the finsih....all is good. If you enter a PM ...say 9:45 PM and 6:15 AM .. you get a negative number .... is there any easy way around this so that it doesnt give a negative value? If you prefer I will ask another question ...I just hate how noone will understand the ground we have covered in this post and they will suggest millions of things that wont apply since they wont read this post.... thanks to both of you !!!
DaveMon
DaveMon
To handle this, I checked if the night start was before the day start. If so, I added a day to the night start value. I also changed the CType to DateTime.Parse.
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim tsDayStart As DateTime
Dim tsNightStart As DateTime
Dim sDaytime As String
Dim sNighttime As String
tsDayStart = DateTime.Parse(txtDaystart
tsNightStart = DateTime.Parse(txtNightsta
If tsNightStart < tsDayStart Then
tsNightStart = tsNightStart.AddDays(1)
End If
sDaytime = (Math.Round(tsNightStart.S
sNighttime = (Math.Round(tsDayStart.Add
lblDaytime.Text = sDaytime
lblNighttime.Text = sNighttime
lblRatio.Text = sDaytime & "/" & sNighttime
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim tsDayStart As DateTime
Dim tsNightStart As DateTime
Dim sDaytime As String
Dim sNighttime As String
tsDayStart = DateTime.Parse(txtDaystart
tsNightStart = DateTime.Parse(txtNightsta
If tsNightStart < tsDayStart Then
tsNightStart = tsNightStart.AddDays(1)
End If
sDaytime = (Math.Round(tsNightStart.S
sNighttime = (Math.Round(tsDayStart.Add
lblDaytime.Text = sDaytime
lblNighttime.Text = sNighttime
lblRatio.Text = sDaytime & "/" & sNighttime
End Sub
SOLUTION
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ASKER
KABOOM !!! that is the solution !!! I really appreciate the help with this problem !!!
many thanks !!!
Dave
many thanks !!!
Dave
ASKER
Dave