comparing dates

[stormcandi]

Hello all,

I am creating a web page using c# to allow a user to select a date from a calendar and then enter a start and end time. The problem I am having is when I have a start time of 10:00 PM and an end time of 1:00 AM, I need to know if the date changes between these two times (passes midnight). I have used the following block to determine if midnight is between these two times, but I cannot get it to work. Can anyone assist?

 
        if (DateTime.Compare(dtMidnight, dtLoginTime) < 0)
        {
            if (DateTime.Compare(dtMidnight, dtLogoffTime) > 0)
            {
                DateTime dtDate = Convert.ToDateTime(strDate);
                dtDate = dtDate.Date;
                dtDate = dtDate.AddDays(1);
                strDate = Convert.ToString(dtDate.Date);
 
                strEndTime = txtEndTime.Text;
                intLength = strEndTime.Length;
                strEndTime = strEndTime.Insert(intLength - 3, ":00");
                strEndTime = strDate + " " + strEndTime;
                dtLogoffTime = Convert.ToDateTime(strDate);
            }
 
        }
 

[SammyB]

I couldn't follow what you were doing, so I just did it from scratch: dateTimePicker1 is the DateTimePicker control from which I only get the start date (not time). txtStart & txtEnd are TextBoxes from which I get the start/stop time. My algorithm is simple: if stop time is less than start time then we have passed midnight. Hopefully, you can understand what I did and adapt it. --Sam

DateTime dtDate = dateTimePicker1.Value.Date;
TimeSpan tsStart = DateTime.Parse(txtStart.Text).TimeOfDay;
TimeSpan tsEnd = DateTime.Parse(txtEnd.Text).TimeOfDay;
DateTime dtStart = dtDate + tsStart;
DateTime dtEnd = dtDate + tsEnd;
if (tsEnd < tsStart)
    dtEnd = dtEnd.AddDays(1.0);
TimeSpan tsOn = dtEnd - dtStart;
MessageBox.Show(tsOn.ToString());

[stormcandi]

Then what about when the start time is 10:00 AM and the end time is 1:00 PM. We did not cross midnight, but the end time is less than the start time.

Or maybe I am misunderstanding the code?

I couldn't follow what you were doing, so I just did it from scratch: dateTimePicker1 is the DateTimePicker control from which I only get the start date (not time). txtStart & txtEnd are TextBoxes from which I get the start/stop time. My algorithm is simple: if stop time is less than start time then we have passed midnight. Hopefully, you can understand what I did and adapt it. --Sam

DateTime dtDate = dateTimePicker1.Value.Date;
TimeSpan tsStart = DateTime.Parse(txtStart.Text).TimeOfDay;
TimeSpan tsEnd = DateTime.Parse(txtEnd.Text).TimeOfDay;
DateTime dtStart = dtDate + tsStart;
DateTime dtEnd = dtDate + tsEnd;
if (tsEnd < tsStart)
    dtEnd = dtEnd.AddDays(1.0);
TimeSpan tsOn = dtEnd - dtStart;
MessageBox.Show(tsOn.ToString());

[SammyB]

Then what about when the start time is 10:00 AM and the end time is 1:00 PM. We did not cross midnight, but the end time is less than the start time.

Or maybe I am misunderstanding the code?

If the start time is 10AM and the end time is 1PM, then start time is less than stop time. Try it: I will too.

[stormcandi]

Ok, I gotcha! Thanks for your help!

If the start time is 10AM and the end time is 1PM, then start time is less than stop time. Try it: I will too.

[SammyB]

Works for me. I think that I'm understanding your problem. You must force the user to enter PM: probably just best to force them to enter AM or PM, just 10:00 is not allowed. --Sam