[RESOLVED] Unexpected malfunction when changing from hours to minutes

[Zach_VB6]

Hey guys!

I have some code that runs on a timer, .Interval = 1000 ms.

Here's the code:

CanTest = CanTest OrElse (DateTime.Now.Subtract(LastTest).Hours >= 1)
If CanTest Then
	If InputBox(Question(Cur), "Question #" & cur.ToString("###,##0")) = Answer(Cur) Then
		Correct += 1
	End If
	Cur += 1
Else
	Dim wait As TimeSpan = LastTest.AddHours(1).Subtract(DateTime.Now)
	Me.Text = "Employee Tester - Waiting " & wait.ToString("mm") & ":" & wait.ToString("ss") 
End If

It works fine... It asks the question, waits an hour, counting down the time to next question in Me.Text - like it should.

However, when I change it to 65 minutes instead of 1 hour, it acts up. The time until next question starts going up instead of down... The only thing I changed is 1 hour to 65 minutes:

CanTest = CanTest OrElse (DateTime.Now.Subtract(LastTest).Minutes >= 65)
If CanTest Then
	If InputBox(Question(Cur), "Question #" & cur.ToString("###,##0")) = Answer(Cur) Then
		Correct += 1
	End If
	Cur += 1
Else
	Dim wait As TimeSpan = LastTest.AddMinutes(65).Subtract(DateTime.Now)
	Me.Text = "Employee Tester - Waiting " & wait.ToString("mm") & ":" & wait.ToString("ss") 
End If

Really confused... Please help!

[03myersd]

What happens if you change all the references to minutes and set the number of minutes to 60?

[dbasnett]

The result of DateTime.Now.Subtract(LastTest) is a TimeSpan. Assuming you want the total time difference you should be using .Totalsomething.

This shows what I am talking about

        Dim dd As TimeSpan = DateTime.Now.Subtract(LastTest)

        Dim hrsD As Double = DateTime.Now.Subtract(LastTest).TotalHours
        Dim minsD As Double = DateTime.Now.Subtract(LastTest).TotalMinutes

[Zach_VB6]

Found the problem - it wasn't with my DateTime arithmetic. When I first called the Timer's .Start(), I never set CanTest = True.

It works with 65 minutes, changing my .Text to:

Me.Text = "Employee Tester - Waiting " & wait.TotalMinutes.ToString("00") & ":" & wait.ToString("ss")

[dbasnett]

Sometimes doing it the long way can be helpful

        Dim CanTest As Boolean = False
        Dim LastTest As DateTime = DateTime.Now.AddMinutes(-65) 'set up for a test
        Dim DiffInDate As TimeSpan = DateTime.Now.Subtract(LastTest)

        If CanTest OrElse DiffInDate.TotalMinutes >= 65 Then
            Stop
        Else
            Stop
        End If

[dbasnett]

Found the problem - it wasn't with my DateTime arithmetic. When I first called the Timer's .Start(), I never set CanTest = True.

It works with 65 minutes, changing my .Text to:

Me.Text = "Employee Tester - Waiting " & wait.TotalMinutes.ToString("00") & ":" & wait.ToString("ss")

Unless you change your check to total minutes the only way the If will ever be true is if CanTest = true. What is this code trying to do?

[Zach_VB6]

Unless you change your check to total minutes the only way the If will ever be true is if CanTest = true. What is this code trying to do?

You're right , changed it to ToatlMinutes --- thanks