Taking a DateTime value and only accepting time and vice versa

Question

I'm currently developing an application to function as a todo - list and i was wondering how do i accept a Value from a date time box, but only use the value of the date, or the value of the time. I'm currently doing it like this.

DateTime ted = appointmentDateTimeDate.Value; //The date
DateTime at = appointmentDateTimeTime.Value;  //The time

should i be doing this another way?

Answer 1

Use DateTime.Date property for date, and DateTime.TimeOfDay for time:

DateTime ted = appointmentDateTimeDate.Date; //The date
TimeSpan at = appointmentDateTimeTime.TimeOfDay;  //The time

Answer 2

The BCL doesn't really separate dates and times nicely.

If you're happy to take a new external dependency, I'd like to plug my Noda Time library, which will let you separate things out clearly into LocalDate and LocalTime . To perform the conversion from a date/time picker you'd probably use:

var dateAndTime = LocalDateTime.FromDateTime(appointmentDateTimeDate.Value);
LocalDate date = dateAndTime.LocalDate;
LocalTime time = dateAndTime.LocalTime;

Answer 3

A DateTime value ALWAYS contains both the date and the time, whether you use both or not.

You can use the . Date property of a DateTime to get "just the date". it will still have a time value, but the time value will be midnight. You can also use the . TimeOfDay property to get the time portion, which will be a TimeSpan indicating the number of ticks since midnight.

I'm taking a leap here and assuming you're trying to set the date with one control an d the time with another in the UI. Here's a sample of some code we use to do this using an Ajax CalendarExtender attached to a textbox and a custom TimePicker control .

    DateTime dt;
    try
    {
        dt = Convert.ToDateTime(txtViewDate.Text).AddHours(txtViewTime.Hour).AddMinutes(txtViewTime.Minute);
        if (txtViewTime.AmPm == MKB.TimePicker.TimeSelector.AmPmSpec.PM)
        {
            dt = dt.AddHours(12);
        }
        System.Diagnostics.Debug.WriteLine(dt.ToString());

    }
    catch (Exception)
    {
        // abort processing
        return;
    }  

Answer 4

Like others pointed out a DateTime always has both a date and a time component. So although it's possible to save both independently using two DateTime , in most cases it's recommendable to save both together in a single DateTime instance.

You should see if you really need both values separated or if your application could combine both in one property, which will make things easier.