DateTime comparison, minus certain timeframe? c#

Say I have these two DateTime objects:

var dt1 = new DateTime(1900,12,1,1,1,1);
var dt2 = new DateTime(1900, 12, 1, 1, 59, 1);

Obviously if I do DateTime.Compare(dt1,dt2) the method will return a value indicating they do not equal the same (because of the 59/minute component).

If I only want comparison with precision restricted to a certain value (i.e. same day - dont care about hours/minutes etc) is the best way to do this just to rebuild each datetime object?

I.e.

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DateTime.Compare(new DateTime(dt1.Year,dt1.Month,dt1.Day,1,1,1),new DateTime(dt2.Year,dt2.Month,dt2.Day,1,1,1))

or is there a smarter way to do this?

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There is already a built in function to get the Date from a DateTime, namely the Date property:

DateTime.Compare(dt1.Date,dt2.Date)

In theory you could compare year, month and day in that order instead of building a new DateTime, but since DateTime is a small struct building it is rather cheap, causes no heap allocations etc. And the code is much more readable.

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If you just want the same date, just compare the Date properties:

dt1.Date == dt2.Date

If you need down to the same hour, or up to the same month, you need to use the constructors as you've shown.

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The same day is easy - just use the Date property:

dt1.Date.CompareTo(dt2.Date)

For other granularities you would probably need to manually build different values though.