[fpc-devel] Recent changes to TField.SetData

[LacaK]

Michael,
do you plan do something else with this "OnValidate" problem ?
Thanks
-Laco.

> 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     S      et.Statein[dsSetKey,dsFilter]thenExit893If
>> 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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>
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