CSHARP

c# how does comparing datetime work

using System;
public class Demo {
   public static void Main(){
      DateTime d1 = new DateTime(2019, 12, 20, 6, 20, 40);
      DateTime d2 = new DateTime(2019, 11, 20, 6, 20, 40);
      Console.WriteLine("DateTime 1 = {0:dd} {0:y}, {0:hh}:{0:mm}:{0:ss} ", d1);
      Console.WriteLine("DateTime 2 = {0:dd} {0:y}, {0:hh}:{0:mm}:{0:ss} ", d2);
      int res = DateTime.Compare(d1, d2);
      // returns equal to 0 since d1 is equal to d2
      Console.WriteLine(res);
   }
}

how to compare datetime in c#

DateTime.Compare(datetime1, datetime2);
/*
datetime1 before datetime2 = -ve
datetime1 equal datetime2 = 0
datetime1 after datetime2 = +ve
*/

C# compare date values

var target = DateTime.Parse("3/25/2020");
var todaysDate = DateTime.Today;

if(target > todaysDate)
{
    Console.WriteLine("Hello World!");
}
else 
{
    Console.WriteLine("Too Bad");
}

c# how to compare 2 dates without time

if(dateTime1.Date == dateTime2.Date)
  // or 
if (dateTime1.Date.CompareTo(dateTime2.Date))
{
}

c# compare dateTime with string

if ( DateTime.Parse(date2,CultureInfo.InvariantCulture) <=  DateTime.Parse(date1,CultureInfo.InvariantCulture))

{
  // perform some code here
}