Use the DaysInMonth to display the number of days in a month.
Add the year and month as a parameter for the DaysInMonth() method −
DateTime.DaysInMonth(2018, 8);
The following is an example −
Example
using System;
using System.Collections.Generic;
using System.Linq;
public class Demo {
public static void Main() {
Console.WriteLine("Today = {0}", DateTime.Today);
int num_days = DateTime.DaysInMonth(2018, 8);
Console.WriteLine("Days in August: "+num_days);
}
}Output
Today = 9/4/2018 12:00:00 AM Days in August: 31