I'm sure this has been covered somewhere before, but I have been unable to locate a solution
TDate fields in an object showing the default date (value 0.0) of 30/12/1899 when bound to a string.
D11.3
I have Objects that arebeing populated from a JSON source.
I have several TDate fields.
The default value set is 0 which equates to 30/12/1899.
Using live bindings to display the objects using a TPrototypeBindSource and a TListBindSourceAdapter<myObject>
I would like to override the default date conversion and show an empty string. I was tTrying to have a way to convert all of the date/dateimes to string with an empty string for whatever default you want to use. Would prefer a global approach to the conversion.
The UI looks a bit crap with the 1899 dates where the JSON had an empty date.
I've looked at the TValueRefConverterFactory and overriding the Date to String converter but the it didnt work as the adapters have their own conversion functions;
in Data.Bind.ObjectScope;
function ConvToText(const ASource: TValue; AType: TScopeMemberType; out AResult: TValue): Boolean;
begin
AResult := ASource.ToString;
Result := True;
end;
Which gets called from here...
procedure TBindSourceAdapterEnumerator.GetMemberValue(const AMemberName: string; const AType: TScopeMemberType;
const ACallback: TValueCallback);
const
LObjectTypes: TScopeMemberTypes = [TScopeMemberType.mtObject, TScopeMemberType.mtBitmap];
var
LMember: TObject;
LMemberType: TScopeMemberType;
LValue: TValue;
LConverter: TConvertFunc;
LResult: TValue;
begin
LMember := FBindSourceAdapter.GetMember(AMemberName);
if (LMember is TBindSourceAdapterField) and TBindSourceAdapterField(LMember).GetMemberType(LMemberType) then
begin
LConverter := Conversions[LMemberType, AType];
LValue := TBindSourceAdapterField(LMember).GetTValue;
Assert(@LConverter <> @ConvFail);
if @LConverter <> @ConvNone then
begin
if LConverter(LValue, AType, LResult) then
ACallback(LResult, AType)
else
Assert(False);
end
else
ACallback(LValue, AType)
end;
end;
But that Type declaration and code sits in the implemetation section so I cant see a way to get to it.....
If there was a way to alter the
const
Conversions: array[TScopeMemberType,TScopeMemberType] of TConvertFunc = (....);
that would be all you need....
Or is there something really basic that Im just missing here.
Ideas anyone?