How to get last day of current month in C# Asp.net?

You can use DaysInMonth() to help return total day of the moth (it's same with last day of the month), see example below:

 int lastDayOfMonth = DateTime.DaysInMonth(DateTime.Now.Year, DateTime.Now.Month);

This code will return last day of the current month. If you want to get last day of any other month, you need to change year & month parameter for function above.

I hope this answer is helpful for you.

It seem easy. You can see code and fomular below:

 DateTime now = DateTime.Now; // get current time
var firstDayOfTheMonth = new DateTime(now.Year, now.Month, 1); // Get first day
var LastDayOfTheMonth = firstDayOfTheMonth.AddMonths(1).AddDays(-1); // Last day = firstday + 1 month - 1 day.

It really worked for me.