Minifycode 2022-08-11 Viewed 6.6K times C#

How to check if a DateTime is Null or Not Null or Empty in C#?


In this article, you will learn, how to check if a DateTime is Null or Not Null or Empty in C#. In this article, we used the more than one ways to check if the Datetime is Null or Not Null or Empty. 

Here are the examples to check if a DateTime is null or not null or empty in C#.

Using !DateTime.HasValue Condition Check

using System;

namespace Minifycode
{
    class Program
    {
        /* How to Check if a DateTime Field is Null or not Null or Empty in C# */
        static void Main(string[] args)
        {

            DateTime Date = new DateTime(2021, 03, 06);
            DateTime? NullDate =null;

            Console.WriteLine("Datetime is Null or Empty: {0}", IsDateTimeNullorEmpty2(Date));
            Console.WriteLine("Datetime is Null or Empty: {0}", IsDateTimeNullorEmpty2(NullDate));


            //Hit ENTER to exit the program
            Console.ReadKey();
        }

        public static bool IsDateTimeNullorEmpty2(DateTime? date)
        {
            return !date.HasValue ? true : false;
        }
    }
}

Output

Datetime is Null or Empty: False

Datetime is Null or Empty: True

using DateTime==null

using System;

namespace Minifycode
{
    class Program
    {
        /* How to Check if a DateTime Field is Null or not Null or Empty in C# */
        static void Main(string[] args)
        {

            DateTime Date = new DateTime(2021, 03, 06);
            DateTime? NullDate =null;

            Console.WriteLine("Datetime is Null or Empty: {0}",IsDateTimeNullorEmpty3(Date));
            Console.WriteLine("Datetime is Null or Empty: {0}", IsDateTimeNullorEmpty3(NullDate));
            //Hit ENTER to exit the program
            Console.ReadKey();
        }

        public static bool IsDateTimeNullorEmpty3(DateTime? date)
        {
            return date == null ? true : false;
        }
    }
}

Output

Datetime is Null or Empty: False

Datetime is Null or Empty: True


If you declare a DateTime, then the default value is DateTime.MinValue, and hence you have to check it like this...

DateTime dt = new DateTime();

 if (dt==DateTime.MinValue)
 {
     //unassigned
 }


If the DateTime is nullable, well that a different story...

DateTime? dat = null;

 if (!dat.HasValue)
 {
     //unassigned
 }


If you are storing your DateTime as an actual string, you can use the String.IsNullOrEmpty() method to determine if it is empty or not : 

//Check if your field is empty
if(String.IsNullOrEmpty(yourDateTimeString))
{
     returnMessage += "Your string was blank. <br />";
}

DateTime objects however cannot be empty as they are not strings and they must have a defined date. I suppose that you could check to see if the Date is equal to the default Date as a measure of determining if a Date was never set...

//Check if your field is empty (the default value)
if(YourDateTime == DateTime.MinValue)
{
     returnMessage += "Your DateTime was blank. <br />";
}

 

how to check if a DateTime is Null or Not Null or Empty in C#?
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