How to check if a DateTime field is not null or empty?

ethanm
ethanm
24 Points
2 Posts

I have table field of type DateTime with allow null in SQL server database. In entity framework , I need to check if the datetime field has null or not.

I try following but not giving correct result:

if(model.myDate==null)
// do if myDate has null value
else
// do if myDate has not null value

What is the correct way to check if datetime has null value?

Views: 57724
Total Answered: 4
Total Marked As Answer: 2
Posted On: 12-Oct-2017 04:18

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Use model.myDate.HasValue. It will return true if date is not null otherwise false.
 - Brian  12-Oct-2017 22:12
Answers
beginer
beginer
1544 Points
52 Posts
         

Try following code:

if(!model.myDate.HasValue)
// do if myDate has null value
else
// do if myDate has not null value
Posted On: 12-Oct-2017 22:48
Smith
Smith
2890 Points
78 Posts
         

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

 

DateTime dat = new DateTime();

if (dat == DateTime.MinValue)
{
   //date is not unassigned
}

If the DateTime is nullable, well that's a different story:

 

DateTime? dat = null;

if (!dat.HasValue)
{
  //date is not unassigned
}
Posted On: 29-Oct-2017 23:02
great ...
 - Priya  05-May-2018 22:26
chatGPT
chatGPT
122 Points
0 Posts
         

We can check if a DateTime field is not null or empty using the DateTime? type (nullable DateTime) and its HasValue property.

DateTime? myDateTime = // assume this value is set somewhere
if (myDateTime.HasValue)
{
    // the DateTime value is not null or empty, so you can use it
    // do something with myDateTime.Value
}

In this example, we are checking if the myDateTime object has a value using the HasValue property. If the property returns true, the DateTime value is not null or empty and you can access it using the Value property.

Alternatively, you can also use the null-coalescing operator (??) to provide a default value in case the DateTime value is null:

DateTime? myDateTime = // assume this value is set somewhere
DateTime defaultDateTime = DateTime.Today; // a default value to use if myDateTime is null

DateTime dateTimeToUse = myDateTime ?? defaultDateTime;

In this example, we are using the null-coalescing operator to assign the value of myDateTime to dateTimeToUse if it is not null, or defaultDateTime if it is null.

Posted On: 19-Apr-2023 06:17
great!
 - Api Test  12-May-2023 07:00
great!
 - Raj  25-Oct-2023 03:27
good!
 - mongo  18-Apr-2024 23:15
mongo
mongo
170 Points
8 Posts
         

Very old post but still valid and helpful.

Posted On: 18-Apr-2024 23:27
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