Question

I want to create some class that can calculate absolute or relative time period.
Meaning: the constructor will get either time period and units ( 3 weeks ) or two DateTime start and finish time. I have wrote the following code :

public class TimePeriod
{

    public State TimePerriodState { get; private set; }
    public RelativeTime RelativeTimePeriod { get; private set; }
    public int UnitsOfTime { get; private set; }

    public DateTime? StartTime { get; private set; }
    public DateTime? EndTime { get; private set; }

    public TimePeriod(RelativeTime relativeTime, int unitsOfTime)
    {
        TimePerriodState = State.Absolute;
        RelativeTimePeriod = relativeTime;
        UnitsOfTime = unitsOfTime;
    }

    public TimePeriod(DateTime startTime , DateTime endTime)
    {
        TimePerriodState = State.Relative;
        StartTime = startTime;
        EndTime = endTime;
    }


    public enum State
    {
        None,
        Absolute,
        Relative
    }

    public enum RelativeTime
    {
        None,
        Hours,
        Days,
        Weeks,
        Months,
        Year
    }
}

But I don’t like that the usage is base on the state.
In the end the data will appear in the UI as two different controls. Is there a better way of making the API little better? Maybe pass in the data and calculate the dateTime on the fly or some thing like that?

UPDATE :

the usage is relative to any time its being used. meaning enter a timespan is not possible. lets say we need fo have the relative time prior 10 days from now or fixed days from X to Y

The TimeSpan will be calculated in a different BL class (this is a POCO class)

Answer 1

You’re basically trying to store the same data twice.

You can define any period of time by either:

• A startdate and enddate, duration can be calculated by subtraction.
• A startdate and duration (TimeSpan), Enddate can be calculated by adding the two.
• You could do it with a duration and enddate but that’s making things harder.

What you want to do is pick one way of storing it. If you want it the other way, write a function to calculate it. E.g:

public TimePeriod(DateTime startTime , DateTime endTime)
{
    StartTime = startTime;
    EndTime = endTime;
}

public TimePeriod(DateTime startTime , TimeSpan length)
{
    StartTime = startTime;
    EndTime = startTime + length;
}

public TimeSpan GetDuration()
{
    return EndTime - StartTime;
}

//Else you can just get the StartTime or EndTime variable (DateTime)