Provides an interface IDateTimeProvider and static container.

Targets netstandard1.3 and net45.

DateTimeProvider exists in the global:: namespace to make usage easier.

The library provides DateTimeOffset, not DateTime. Why? Read this excellent answer on StackOverflow

DateTimeOffset is great, however there are use-cases where you need to use DateTime as Local or UTC.

You can use DateTimeOffset.LocalDateTime and DateTimeOffset.UtcDateTime properties. For convenience, our static DateTimeProvider has these properties as LocalNow and UtcNow.

Install the Nuget package.

Install-Package DateTimeProvider

Set the provider

DateTimeProvider.Provider = new UtcDateTimeProvider();

Or

DateTimeProvider.Provider = new LocalDateTimeProvider();

NB The default is UtcDateTimeProvider.

Then use or replace in place of DateTime in your code.

var now = DateTimeProvider.Now;
var local = DateTimeProvider.LocalNow;
var utc = DateTimeProvider.UtcNow;

Also provided is a static IDateTimeProvider and IDisposable Override so that time can be manipulated in a fixed scope.

Why is this useful?

• In a web request, you want to freeze time so that all your modified dates are aligned (i.e. not +/- by a few seconds)
• In unit tests when you need to verify business logic.

using (var o = new OverrideDateTimeProvider(DateTimeProvider.Now))
{
    // logic
}

In your tests, you need may need to manipulate time to verify your logic. This is easy using the OverrideDateTimeProvider.

Console.WriteLine($"{DateTimeProvider.Now}");

var testingWithDate = new DateTimeOffset(new DateTime(2014, 10, 01), TimeSpan.FromHours(8));
using (var o = new OverrideDateTimeProvider(testingWithDate))
{
    Console.WriteLine($"{DateTimeProvider.Now} (Testing)");
    o.MoveTimeForward(TimeSpan.FromHours(5));
    Console.WriteLine($"{DateTimeProvider.Now} (+ 5 hours)");
}

Console.WriteLine($"{DateTimeProvider.Now} (Restored)");

Output

6/11/2015 5:08:12 AM +00:00
1/10/2014 12:00:00 AM +08:00 (Testing)
1/10/2014 5:00:00 AM +08:00 (+ 5 hours)
6/11/2015 5:08:12 AM +00:00 (Restored)

Also available is a Roslyn Analyser that will suggest replacements for DateTime for DateTimeProvider.

Install the Nuget package.

Install-Package DateTimeProvider.Analyser

MIT