[fpc-devel] Recent changes to TField.SetData

[LacaK]

Hi,
here are diffs with changes, I hope they will be good for all TDataSet 
descendants (those specific to FPC and also those which are also for use 
in Delphi)
Code which is general (and is used repeatedly) is placed in TField 
methods and only small code remains which must be placed into each 
TDataSet descendant.
(I patched only TBufDataSet, but later can be updated also other 
TDataSet descendants ... remove redundant code and add Field.Validate(...))
Thanks
-Laco.

>
>>>> The whole code, which is repeated (and can be put in one place) is:
>>>>
>>>> if not (State in [dsEdit, dsInsert, dsFilter, dsCalcFields]) then
>>>> begin
>>>>   DatabaseErrorFmt(SNotEditing,[Name],self);
>>>>   exit;
>>>> end;
>>>> if (Field.FieldNo>0) and not (State in [dsSetKey, dsFilter]) then
>>>> begin
>>>>   if Read     
>>>> OnlythenDatabaseErrorFmtSReadOnlyField,[Field.DisplayName],
>>>> Self);
>>>>   Field.Validate(Buffer);
>>>> end;
>>>
>>> You are right in your dislike.
>>>
>>> I will create a 'BeforeSetFieldData' in TDataset and put the code in 
>>> there,
>>> and the same for 'AfterSetFieldData' with the OnChange code.
>>>
>> OK,
>> Then please do not forget commit necessary changes also in other 
>> descendants (not only in TCustomBufDataSet but also in TParadox, 
>> TMemDataset,  TFixedFormatDataSet,  TDbf) to completelly fix 'missing 
>> onvalidate call' problem.
>> Thanks
>>
> I am still thinking about this.
> I have other solution, which is relative simple , puts base logic into 
> base TField methods (so all TDataSet descendants can benefit from it) 
> and does not negatively affect existing TDataSet descendants and does 
> not require introduce new methods (BeforeSetFieldData, 
> AfterSetFieldData).
> Let's distributes repeating used code as follows:
>
> 1. base checks "before" into procedure TField.SetData(Buffer: Pointer; 
> NativeFormat : Boolean);
>
>  820 begin
>  821   If Not Assigned(FDataset) then
>  822     DatabaseErrorFmt(SNoDataset,[FieldName]);
>
>        if not (State in [dsEdit, dsInsert, dsFilter, dsCalcFields]) 
> then //here should be IMO also dsNewValue
>          DatabaseErrorFmt(SNotEditing,[FDataSet.Name],FDataSet);
>
>        if ReadOnly and (FieldNo>0) and not (FDataSet.State in 
> [dsSetKey, dsFilter]) then
>          DatabaseErrorFmt(SReadOnlyField, [DisplayName], Self);
>
>  829   FDataSet.SetFieldData(Self,Buffer, NativeFormat);
> -------------------------------------------------------------------------- 
>
>
> 2. into procedure TField.Validate(Buffer: Pointer);
>
>  892 begin
>        if FData     Set.Statein[dsSetKey,dsFilter]thenExit  893   If 
> assigned(OnValidate) Then
>
> -------------------------------------------------------------------------- 
>
>
> 3. "after call" into procedure TDataSet.SetFieldData(Field: TField; 
> Buffer: Pointer);
>     begin
>       if not (State in [dsCalcFields, dsFilter, dsNewValue]) then
>         DataEvent(deFieldChange, Ptrint(Field));
>     end;
>
> -------------------------------------------------------------------------- 
>
>
> And now all what we must do, is put into method SetFieldData in 
> TDataSet descendants one line:
>
> Field.Validate(Buffer);
> and one line at end:
>
> inherited; //calls "field change" ... this is done by all TDataSet 
> descendants in fcl-db as a last thing
>
>
> It is only draft, so some detils may be changed ... ;-)
> What do you think ?
>
> Laco.
>
>

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