I have this code
type
TXSample = (xsType1, xsType2, xsType3, xsType4, xsType5, xsType6, xsType6, xsTyp7, xsType8); // up to FXSample30;
..
private
FXSample = Set of TXSample;
..
published
property Sample: TXSample read FXSample write FXSample;
..
//if Sample has a value of
Sample := [xsType2, xsType4, xsType5, xsType6, xsTyp7];
how can i save/load the property of Sample?
i would like to save it in the database.
is it possible?
Provided your set will never exceed 32 possibilities (Ord(High(TXSample)) <= 31
), then it is perfectly fine to typecast the set into an Integer
and back:
type
TXSamples = set of TXSample;
var
XSamples: TXSamples;
begin
ValueToStoreInDB := Integer(XSamples);
Integer(XSamples) := ValueReadFromDB;
end;
To be more specific: SizeOf(TXSamples)
has to be precisely equal to SizeOf(StorageTypeForDB)
. Thus the following ranges apply for Ord(High(TXSample))
when typecasting TXSamples
to:
Byte: Ord(High(TXSample)) < 8
Word: 8 <= Ord(High(TXSample)) < 16
Longword: 16 <= Ord(High(TXSample)) < 32
UInt64: 32 <= Ord(High(TXSample)) < 64