CODEWITHSUNDEEP
c#datetimedatetimeoffset
VSO
VSO

Reputation: 12636

Comparing Dates Only on DateTime/DateTimeOffset Objects

I receive a DateTime from the client: DateTime CurrentTimeOnClient
I have a DateTimeOffset I get from the db: DateTimeOffset DateTimeOffsetFromDb

I need to compare the two dates, IGNORING the time AND time zone. In other words, I just want the raw date from both objects. I tried using FooDateTimeOffset.DateTime.Date but it seems to still factor in the time, so what I have now is this:

DateTimeOffset clientDateTimeOffSet = DateTime.SpecifyKind(CurrentTimeOnClient, DateTimeKind.Utc);
clientDateTimeOffSet = await RemoveTimeComponentFromDateTimeOffset(clientDateTimeOffSet);
clientDateTimeOffSet = await SetTimeZoneOffsetToZero(clientDateTimeOffSet);

And the helper methods:

public async Task<DateTimeOffset> SetTimeZoneOffsetToZero(DateTimeOffset dateTimeOffSetObj)
{
    TimeSpan zeroOffsetTimeSpan = new TimeSpan(0, 0, 0, 0, 0);
    return dateTimeOffSetObj.ToOffset(zeroOffsetTimeSpan);
}

public async Task<DateTimeOffset> RemoveTimeComponentFromDateTimeOffset(DateTimeOffset dateTimeOffSetObj)
{
    DateTime dateWithZeroedTime = new DateTime(dateTimeOffSetObj.Year, dateTimeOffSetObj.Month, dateTimeOffSetObj.Day, 0, 0, 0);
    return dateWithZeroedTime; 
}

Then I clean the DateTimeOffset obj from the db in the same way (though obviously without the need to convert them) and compare them. 

bool foo = dateFromDb > dateFromClient;

P.S. I am aware that these questions HAVE been answered separately, but I would like to see if I made any glaring mistakes or if I am overdoing it. (but again, the suggested .Date solution doesn't seem to work).

Edit: @James

    //TESTING
    var testDateAndTime = new DateTimeOffset(2008, 5, 1, 8, 6, 32,new TimeSpan(1, 0, 0));
    //This is just some db object that has a date field that I had on hand
    var anncmnt = db.Announcements.First(a => a.Id == 13);

    //CLEAN TIME AND DATE
    testDateAndTime = testDateAndTime.DateTime.Date; 

    anncmnt.EndDate = testDateAndTime;
    await db.SaveChangesAsync(); 
    //TESTING

Db Result: 2008-05-01 00:00:00.0000000 -04:00

Upvotes: 3

Views: 8996

Answers (2)

James Fegan
James Fegan

Reputation: 129

Forgot UTC. Try using the SpecifyKind method. It appears to give what you need and passes my quick unit test below:

        //TESTING
        for (var hr = 0; hr < 24; hr++)
        {
            var testDateAndTime = new DateTimeOffset(2008, 5, 1, hr, 6, 32, new TimeSpan(1, 0, 0));
            var noOffsetDate = DateTime.SpecifyKind(testDateAndTime.Date, DateTimeKind.Utc);
            Console.WriteLine(noOffsetDate);
        }

Upvotes: 1

Godrules500
Godrules500

Reputation: 469

That is weird that the .Date() doesn't work. This is something I've done in the past when addressed with an issue like this. I parse the datetime date string then compare. So I do the below code.

dateFromDb = DateTime.Parse(dateFromDb.ToShortDateString());
dateFromClient= DateTime.Parse(dateFromClient.ToShortDateString());

Then try comparing it and see if that works?

Upvotes: 1

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