How to display empty string instead of 30.12.1899 in case of NULL date

[krzynio]

Hello!

How to display empty string in TDBDateEdit instead of 30.12.1899 in case of NULL or zero date?
30.12.1899 looks inelegant.

Lazarus 3.6 on Windows 11.

[Zvoni]

Hello!

How to display empty string in TDBDateEdit instead of 30.12.1899 in case of NULL or zero date?
30.12.1899 looks inelegant.

Lazarus 3.6 on Windows 11.

What's the SQL-Statement looks like?

[paweld]

Use TDBDateTimePicker (the DateTimeCtrls package) instead of TDBDateEdit.

[wp]

The attached project demonstrates that TDBEdit is able to display an empty field, but only when the field is null.

TDBDatePicker, on the other hand, has the issue that it ignores an empty string in its TextForNullDate property and displays a "zero" date ("00.00.0000"). This can be fooled, however, by setting TextForNullDate to a space character.

[Zoran]

TDBDatePicker, on the other hand, has the issue that it ignores an empty string in its TextForNullDate property and displays a "zero" date ("00.00.0000"). This can be fooled, however, by setting TextForNullDate to a space character.

This is not an issue, but it is by design and documented:

If you want empty display, this can be achieved by setting TextForNullDate to one or more space characters.

[five]

How to display empty string in TDBDateEdit instead of 30.12.1899 in case of NULL or zero date?
30.12.1899 looks inelegant.

If often use Field.OnGetText event to format and control the displayed text for a Tfield.

Code: Pascal  [Select][+][-]

1. procedure TForm1.DataSetDatetimeGetText(Sender: TField; var Text: string;
2.   DisplayText: Boolean);
3. begin
4.   try
5.     { Display the contents according to the value of the date }
6.     If Sender.IsNull then
7.         Text := ''
8.     else
9.        Text := Sender.AsString;
10.  
11.   except
12.     { on error set the default text }
13.     Text := Sender.AsString;
14.   end;
15. end;
16.  
17.  
18.  

[krzynio]

Use TDBDateTimePicker (the DateTimeCtrls package) instead of TDBDateEdit.

Thank you!
I think this is the simplest solution. I ran away from it because it wasn't on the standard component palette, and DBDateEdit didn't exist at all. So as soon as it appeared in the basic palette, I replaced all TDBDateTimePickers with DBDateEdit and that surprised me.
I'am considering your solution.
Ragards/Pozdrawiam,
Krzysztof

[krzynio]

The attached project demonstrates that TDBEdit is able to display an empty field, but only when the field is null.

TDBDatePicker, on the other hand, has the issue that it ignores an empty string in its TextForNullDate property and displays a "zero" date ("00.00.0000"). This can be fooled, however, by setting TextForNullDate to a space character.

Thank you!
I tried with TDBDatePicker and TextForNullDate property but TextForNullDate seems to be missing in Lazarus 3.6 and FPC 3.2.2
Br, Krzysztof

[krzynio]

How to display empty string in TDBDateEdit instead of 30.12.1899 in case of NULL or zero date?
30.12.1899 looks inelegant.

If often use Field.OnGetText event to format and control the displayed text for a Tfield.

Code: Pascal  [Select][+][-]

1. procedure TForm1.DataSetDatetimeGetText(Sender: TField; var Text: string;
2.   DisplayText: Boolean);
3. begin
4.   try
5.     { Display the contents according to the value of the date }
6.     If Sender.IsNull then
7.         Text := ''
8.     else
9.        Text := Sender.AsString;
10.  
11.   except
12.     { on error set the default text }
13.     Text := Sender.AsString;
14.   end;
15. end;
16.  
17.  
18.  

This looks really fine and worth of implementation not only in this control.
But in this case, for me, it is less comfortable than going back to TDBDateTimePicker.
My only regret is that instead of a nice calendar icon there is just a plain triangle.
Thank you & BR, Krzysztof