Devart Forums

Posted: **Tue 10 Oct 2006 13:02**

Hi,

I just found that at runtime :

If Query['MyDate'].IsNull then DoSomething();

get an EVariant Invalide OP error with message : Invalid variant operation
while

If Query.FieldByName('MyDate').IsNull then DoSomething();

worked like a charm !

Is this a VCL bug or a MyDAC bug ?

Ps : MyDate is a TDateTimefield type

Posted: **Tue 10 Oct 2006 15:02**

This is not a bug. These lines are not equal because this call

  Query['MyDate']

returns value of Variant type, but this one

  Query.FieldByName('MyDate')

returns value of TField type. TField has IsNull method implemented but Variant does not. Following three calls are equal:

  Query['MyDate']
  Query.FieldValues['DName']
  Query.FieldByName('MyDate').Value

Posted: **Wed 11 Oct 2006 09:34**

Thank you for this explaination

MyDAC or VCL Bug ?