How to check if date is less than or equals to today's date?

Question

I need to determined if the date entered by the user is less than or equals to today's date.

I have the following code which converts the dates to int and than compare their values. Is there a more efficient or lean way to get this accomplished with less lines of code?

How do I do this with far less code or extraneity?

Code:

class Program
{
    public static bool IsDateBeforeOrToday(string input)
    {
        bool result = true;

        if(input != null)
        {
            DateTime dTCurrent = DateTime.Now;
            int currentDateValues = Convert.ToInt32(dTCurrent.ToString("MMddyyyy"));
            int inputDateValues = Convert.ToInt32(input.Replace("/", ""));

            result = inputDateValues <= currentDateValues;
        }
        else
        {
            result = true;
        }

        return result;
    }

    static void Main(string[] args)
    {
        Console.WriteLine(IsDateBeforeOrToday("03/26/2015"));
        Console.ReadKey();
    }
}

Answer 1

Instead of converting current date to string and then int and doing the comparison, convert your parameter date string to DateTime object and then compare like:

var parameterDate = DateTime.ParseExact("03/26/2015", "MM/dd/yyyy", CultureInfo.InvariantCulture);
var todaysDate = DateTime.Today;

if(parameterDate < todaysDate)
{
}

You can have your method as:

public static bool IsDateBeforeOrToday(string input)
{
    DateTime pDate;
    if(!DateTime.TryParseExact(input, "MM/dd/yyyy", CultureInfo.InvariantCulture, DateTimeStyles.None, out pDate))
    {
        //Invalid date
        //log , show error
        return false;
    }
    return DateTime.Today <= pDate;
}

• Use DateTime.TryParseExact if you want to avoid exception in parsing.
• Use DateTime.Today if you only want to compare date and ignore the time part.

Answer 2

You could use the DateTime.Compare method. You could do this:

DateTime dTCurrent = DateTime.Now;
DateTime inputDate = DateTime.ParseExact(input, "MM/dd/yyyy", CultureInfo.InvariantCulture);

int result = DateTime.Compare(dTCurrent, inputDate);

The int 'result' would indicate if dTCurrent is less than inputDate (less than 0), same as (0) or greater than (greater than 0).