While .NET has several types to work with time, there are times when these types are not very handy to use.

TimeSpan represents a time interval it ticks. In most cases it’s fine but when you are working with, for example, reports you are dealing with time units like days, hours, minutes. And it becames not handy to work with time units by using TimeSpan

So let’s introduce the new enumeration which represents the time units.

public enum TimeUnit : long
{
	Microsecond = 10L,
	Millisecond = 10000L,
	Second = 10000000L,
	Minute = 600000000L,
	Hour = 36000000000L,
	Day = 864000000000L
}

As you can see, each item in enumeration has value that equals to the number of ticks in the time unit that it represents. Unfortunately it is impossible to describe such time units as Month and Year because count of ticks in different months differs.

The set of extensions methods that allows TimeUnit to work with DateTime

/// <summary>
/// Adds <paramref name="timeUnit"/> to the <paramref name="value"/>.
/// </summary>
public static DateTime Add(this DateTime value, TimeUnit timeUnit)

/// <summary>
/// Subtracts <paramref name="timeUnit"/> from the <paramref name="value"/>.
/// </summary>
public static DateTime Subtract(this DateTime value, TimeUnit timeUnit)

/// <summary>
/// Returns the smallest <see cref="DateTime"/> value that is greater than or equal to
/// the specified <paramref name="value"/> within the specified <paramref name="timeUnit"/>.
/// </summary>
public static DateTime Ceiling(this DateTime value, TimeUnit timeUnit)

/// <summary>
/// Returns the largest <see cref="DateTime"/> that less than or equal to
/// the specified <paramref name="value"/> within the specified <paramref name="timeUnit"/>.
/// </summary>
public static DateTime Floor(this DateTime value, TimeUnit timeUnit)