Generic DateTime List Comparison in C#

Question

I have a Generic DateTime List

List<DateTime> **PreviousDates** = //Some List of Dates

Now i want to Get all the Dates in the PreviousDates List whose Month and Year equals the GivenDate's Month & Year. no matter what the Day & Time are...

I Tried using List.Contains() method, but it checks all Parts of the Date, i want to check only Month&Year..

Help Me!

Thanks Pradeep

Answer 1

You need to use the Where method. It will filter the list, and you can compare the Year and Month to the current date.

DateTime currentDate = DateTime.Now;
var filteredDates = previousDates.Where(
    d => d.Year == currentDate.Year && d.Month == currentDate.Month);

Answer 2

您可以使用LINQ返回IEnumerable

PreviousDates.Where(d => d.Month == month && d.Year == year);

Answer 3

You can try something like

DateTime criteria = DateTime.Today;
List<DateTime> filtered = previousDates.Where(dt => dt.Month == criteria.Month && dt.Year == criteria.Year).ToList();

Answer 4

previousDates.Where(d => d.Month == refDate.Month && d.Year == refDate.Year);

Answer 5

You can create DateTime values for the start and end of the interval:

DateTime start = new DateTime(GivenDate.Year, GivenDate.Month, 1);
DateTime end = start.AddMonths(1);

Now you can easily select the items that is inside the interval:

List<DateTime> inside =
  PreviousDates
  .Where(d => d >= start && d < end)
  .ToList();

(You could of course compare the GivenDate.Year and GivenDate.Month values to d.Year and d.Month in the Where , but that's a more complex and less efficient condition.)