Problem in campareing datetime

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hii i am facing a problem in my code in which i am comparing today's date with the date in database this is my code. Here label10.Text is containing the date from database. Basically i am making a reminder app. If the database date matches with todays date then it should send a reminder email

DateTime dt = DateTime.Parse(label10.Text);
            long t = dt.ToFileTime();
            DateTime date1 = DateTime.Today;
            DateTime date2 = new DateTime(t);
            //DateTime date2 = new DateTime(Convert.ToInt64(label10.Text));
            //DateTime date2 = new DateTime(2015,9,16);
            int result = DateTime.Compare(date1, date2);
            string relationship;
            if (result > 0)
            {
                relationship = "is earlier than";
                //SendEmail();               
            }
            else if (result == 0)
            {
                relationship = "is the same time as";
                SendEmail();
                //MessageBox.Show("is same");
            }
            
            else
            {
                relationship = "is later than";
                SendEmail();
                //MessageBox.Show("is later");
            }
            Console.WriteLine("{0} {1} {2}", date1, relationship, date2);

Now the problem is when i run the application the date2 gets filled with 29.09.15 whereas label 10 shows 30.09.15. i am not getting why it is happening

Posted 29-Sep-15 20:59pm

Member 11647575

Updated 29-Sep-15 21:42pm

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phil.o 30-Sep-15 3:06am

And what is the problem? You did not define it.

Member 11647575 30-Sep-15 3:40am

lol.. sorry i forgot to write the problem... when ever i run the program, In date 2 the date which is coming is one day less than the date saved in db.. spouse today is 30.09.15(in date1 todays date is displayed) and in database also a reminder is set to 30.09.15 but when i run the program date2 gets filled with 29.09.15

phil.o 30-Sep-15 4:05am

You do not need the date2 variable, you already have the dt variable. There is no need to get a filetime from dt to create date2 with. Use dt variable directly.

Member 11647575 30-Sep-15 4:29am

can you please explain me why date2 was getting filled with the date oneday less than the db date ??

phil.o 30-Sep-15 4:37am

Yes (you could have got it yourself by just consulting the documentation).
DateTime.ToFileTime return a long value, which is the number of 100-nanoseconds intervals elapsed since January, 1601 1st (UTC).
DateTime constructor accepting a long value constructs a DateTime from the number of 100-nanoseconds intervals elapsed since January, 0001 1st.
Thus, the way you are using these property and constructor is inappropriate.
Sources:
DateTime.ToFileTime Method
DateTime Constructor (Int64)
Moreover, you already have the dt variable. You do not need the date2 one.

Member 11647575 30-Sep-15 4:25am

thanx ,. it helped app is running now..

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OriginalGriff · Answer 1 · 2015-09-29T21:16:00

OK - never compare DateTime values for absolute equality: they are accurate to a tick[^], which is one ten millionth of a second.

That means that in practice there is very, very little chance that your code will ever match equality precisely.

So instead, consider checking the difference:

C#

Timespan diff = date1 - date2;
if (diff.TotalSeconds < 0)
   ...
else if (diff.TotalSeconds == 0)
   ...
else 
   ...

That at least gives you a one-second window in which it will match (or if your timer is not that accurate, use TotalMinutes instead)