The Wiert Corner – irregular stream of stuff

Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

  • My badges

  • Twitter Updates

    • RT @michaelbolton: 1) Your periodic reminder: a test is not something we *write*. We write text and programs. A test is an experiment you *… 1 hour ago
    • RT @BiancaPrins: Voor ons allemaal, een #draadje om tot het einde te lezen..... Juist nu (Volgt nog meer in de komende dagen)… 1 hour ago
    • RT @McKayMSmith: 90) His entire life, Ben has chosen to place his faith in the law. “Law, not war” has been his motto for decades. “I hav… 1 hour ago
    • RT @McKayMSmith: 82) “It's possible to take the most fundamental, strongly held ideas and change them. What makes people change? Sometimes… 1 hour ago
    • RT @McKayMSmith: 65) “Now I will tell you something very profound, which I have learned after many years. War makes murderers out of otherw… 1 hour ago
  • My Flickr Stream

  • Pages

  • All categories

  • Enter your email address to subscribe to this blog and receive notifications of new posts by email.

    Join 1,640 other followers

Spring4D How to correctly assign NULL to a Nullable type?

Posted by jpluimers on 2018/12/19

Since I tend to forget this: [WayBack] Spring4D How to correctly assign NULL to a Nullable type? this is correct? fDateTime = Null; or this? fDateTime := nil; – Jacek Laskowski – Google+

The preferred way is fDateTime := nil.

This is possible because of [WayBack] Delphi sorcery: How to create an operator overload that only accepts nil using a reference type (in this case interface) so no non-nil pointers can be passed:

  Nullable<T> = record
  strict private type
    Null = interface end;
    class operator Implicit(const value: Null): Nullable<T>;


2 Responses to “Spring4D How to correctly assign NULL to a Nullable type?”

  1. Jacek said

    you often quote me here ;-)

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: