Date Comparison Question

[MarkAurit]

Im having difficulty coming up with a good algorithm to express the following
comparison:

"if <a given date> falls between the (current date - 5 days) and the
(current date)"
Obviously. DateTime.Now and something like (AddDays(DateTi me.Now,-5) are used
for the inner and outer ranges, its how to express the "between" that has me.

/* what Id like to do, in pseudo code */
dateToTest=Date Time.Parse("mm/dd/yy");
maxDate=DateTim e.Now;
minDate=DateTim e.Now.AddDays(-5);
bool b1=IsBetween(mi nDate,maxDate,d ateToTest);

Thanks, Mark

[Sean Hederman]

Haven't tested this, so be warned...

private bool IsBetween(DateT ime startDate, DateTime endDate, DateTime date)
{
TimeSpan startSpan = startDate - date;
if(startSpan.Da ys > 0) { // Dunno if you want to use days or
something finer grained
// Also not sure if you want
inclusive or not
TimeSpan endSpan = endDate - date;
if(endSpan.Days > 0) {
return true;
}
}

return false;

}

"MarkAurit" <Ma*******@disc ussions.microso ft.com> wrote in message
news:C3******** *************** ***********@mic rosoft.com...

Im having difficulty coming up with a good algorithm to express the
following
comparison:

"if <a given date> falls between the (current date - 5 days) and the
(current date)"
Obviously. DateTime.Now and something like (AddDays(DateTi me.Now,-5) are
used
for the inner and outer ranges, its how to express the "between" that has
me.

/* what Id like to do, in pseudo code */
dateToTest=Date Time.Parse("mm/dd/yy");
maxDate=DateTim e.Now;
minDate=DateTim e.Now.AddDays(-5);
bool b1=IsBetween(mi nDate,maxDate,d ateToTest);

Thanks, Mark

[William Stacey [MVP]]

private void button16_Click( object sender, System.EventArg s e)
{
DateTime givenDate = DateTime.Now;
DateTime startDate = DateTime.Now.Su btract(TimeSpan .FromDays(5));
DateTime endDate = DateTime.Now;

// Test a date inside the range.
if ( Utils.DateBetwe en(startDate, endDate, givenDate) )
Console.WriteLi ne("Date is between");
else
Console.WriteLi ne("Date is not between");

// Test with a date outside the range.
givenDate = startDate.Subtr act(TimeSpan.Fr omSeconds(1));
if ( Utils.DateBetwe en(startDate, endDate, givenDate) )
Console.WriteLi ne("Date is between");
else
Console.WriteLi ne("Date is not between");
}

/// <summary>
/// Returns true if date is between start and end date inclusive. Put in
some static class, etc.
/// </summary>
public static bool DateBetween(Dat eTime start, DateTime end, DateTime date)
{
if ( date >= start && date <= end )
return true;
return false;
}

// Output
Date is between
Date is not between

--
William Stacey, MVP
http://mvp.support.microsoft.com

"MarkAurit" <Ma*******@disc ussions.microso ft.com> wrote in message
news:C3******** *************** ***********@mic rosoft.com...

Im having difficulty coming up with a good algorithm to express the following comparison:

"if <a given date> falls between the (current date - 5 days) and the
(current date)"
Obviously. DateTime.Now and something like (AddDays(DateTi me.Now,-5) are used for the inner and outer ranges, its how to express the "between" that has me.
/* what Id like to do, in pseudo code */
dateToTest=Date Time.Parse("mm/dd/yy");
maxDate=DateTim e.Now;
minDate=DateTim e.Now.AddDays(-5);
bool b1=IsBetween(mi nDate,maxDate,d ateToTest);

Thanks, Mark

[Jon Skeet [C# MVP]]

MarkAurit <Ma*******@disc ussions.microso ft.com> wrote:

Im having difficulty coming up with a good algorithm to express the following
comparison:

"if <a given date> falls between the (current date - 5 days) and the
(current date)"
Obviously. DateTime.Now and something like (AddDays(DateTi me.Now,-5) are used
for the inner and outer ranges, its how to express the "between" that has me.

/* what Id like to do, in pseudo code */
dateToTest=Date Time.Parse("mm/dd/yy");
maxDate=DateTim e.Now;
minDate=DateTim e.Now.AddDays(-5);
bool b1=IsBetween(mi nDate,maxDate,d ateToTest);

if (dateToTest >= minDate && dateToTest <= maxDate)
{
....
}

--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[Sean Hederman]

"Jon Skeet [C# MVP]" <sk***@pobox.co m> wrote in message
news:MP******** *************** *@msnews.micros oft.com...

MarkAurit <Ma*******@disc ussions.microso ft.com> wrote:

Im having difficulty coming up with a good algorithm to express the
following
comparison:

"if <a given date> falls between the (current date - 5 days) and the
(current date)"
Obviously. DateTime.Now and something like (AddDays(DateTi me.Now,-5) are
used
for the inner and outer ranges, its how to express the "between" that has
me.

/* what Id like to do, in pseudo code */
dateToTest=Date Time.Parse("mm/dd/yy");
maxDate=DateTim e.Now;
minDate=DateTim e.Now.AddDays(-5);
bool b1=IsBetween(mi nDate,maxDate,d ateToTest);
if (dateToTest >= minDate && dateToTest <= maxDate)
{
...
}

Ohhhh bugger! There I was happily playing around with op_Subtract and
TimeSpans and I completely forgot that DateTime supported the comparison
operators...

--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[MarkAurit]

Thanks, Jon.
This fixes that issues of comparison. However, my problem is more subtle:
even if the date is the same, the test isnt correctly working because the
time isnt the same. Im taking a date which comes from a business object
where its defined as a string - even if its todays date, when I perform a
DateTime.Parse on it and equality comparing it to DateTime.Now, the test is
false.
So: I need to compare only the date part of a DateTime, and I have to test
for greater than (if its was always equality, I could ToDateString()) .
Any help is hugely appreciated.
"Jon Skeet [C# MVP]" wrote:

MarkAurit <Ma*******@disc ussions.microso ft.com> wrote:

Im having difficulty coming up with a good algorithm to express the following
comparison:

"if <a given date> falls between the (current date - 5 days) and the
(current date)"
Obviously. DateTime.Now and something like (AddDays(DateTi me.Now,-5) are used
for the inner and outer ranges, its how to express the "between" that has me.

/* what Id like to do, in pseudo code */
dateToTest=Date Time.Parse("mm/dd/yy");
maxDate=DateTim e.Now;
minDate=DateTim e.Now.AddDays(-5);
bool b1=IsBetween(mi nDate,maxDate,d ateToTest);

if (dateToTest >= minDate && dateToTest <= maxDate)
{
....
}

--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[Jon Skeet [C# MVP]]

MarkAurit <Ma*******@disc ussions.microso ft.com> wrote:

This fixes that issues of comparison. However, my problem is more subtle:
even if the date is the same, the test isnt correctly working because the
time isnt the same. Im taking a date which comes from a business object
where its defined as a string - even if its todays date, when I perform a
DateTime.Parse on it and equality comparing it to DateTime.Now, the test is
false.
So: I need to compare only the date part of a DateTime, and I have to test
for greater than (if its was always equality, I could ToDateString()) .
Any help is hugely appreciated.

Just use the Date property of DateTime to get a DateTime with an empty
time portion. You can use DateTime.Today to get the equivalent of
DateTime.Now.Da te.

--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too