How to convert DateTime? to DateTime

user_112023 0
Viewed 253965

I want to convert a nullable DateTime (DateTime?) to a DateTime, but I am getting an error:

Cannot implicitly convert type 'System.DateTime?' to 'System.DateTime'. An explicit conversion exists (are you missing a cast?)

I have attempted the following:

DateTime UpdatedTime = (DateTime)_objHotelPackageOrder.UpdatedDate == null 
    ? DateTime.Now : _objHotelPackageOrder.UpdatedDate;
datetime .net c#
12 Answers

You want to use the null-coalescing operator, which is designed for exactly this purpose.

Using it you end up with this code.

DateTime UpdatedTime = _objHotelPackageOrder.UpdatedDate ?? DateTime.Now;
chills42_238550

MS already made a method for this, so you dont have to use the null coalescing operator. No difference in functionality, but it is easier for non-experts to get what is happening at a glance.

DateTime updatedTime = _objHotelPackageOrder.UpdatedDate.GetValueOrDefault(DateTime.Now);
user_509000

Try this

DateTime UpdatedTime = _objHotelPackageOrder.UpdatedDate ?? DateTime.Now;
Valentin_Vasiliev_4302540

You need to call the Value property of the nullable DateTime. This will return a DateTime.

Assuming that UpdatedDate is DateTime?, then this should work:

DateTime UpdatedTime = (DateTime)_objHotelPackageOrder.UpdatedDate == null ? DateTime.Now : _objHotelPackageOrder.UpdatedDate.Value;

To make the code a bit easier to read, you could use the HasValue property instead of the null check:

DateTime UpdatedTime = _objHotelPackageOrder.UpdatedDate.HasValue
                          ? _objHotelPackageOrder.UpdatedDate.Value
                          : DateTime.Now;

This can be then made even more concise:

DateTime UpdatedTime = _objHotelPackageOrder.UpdatedDate ?? DateTime.Now;
user_1169230

How about the following:

DateTime UpdatedTime = _objHotelPackageOrder.UpdatedDate.HasValue ? _objHotelPackageOrder.UpdatedDate.value : DateTime.Now;
user_128750

Try this:

DateTime UpdatedTime = (DateTime)_objHotelPackageOrder.UpdatedDate == null ? DateTime.Now : _objHotelPackageOrder.UpdatedDate.Value;
user_1070090

You can also use the IS operator starting with C# 7.0:

DateTime UpdatedTime = (_objHotelPackageOrder.UpdatedDate is DateTime myDate) ? myDate : DateTime.Now;

Or in a case distinction

if (_objHotelPackageOrder.UpdatedDate is DateTime UpdatedTime)
{
   ...
}

For the sake of completeness.

user_74620940
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