Re: [fpc-devel] Recent changes to TField.SetData

[michael . vancanneyt]

On Tue, 26 Apr 2011, LacaK wrote:

Michael,
do you plan do something else with this "OnValidate" problem ?

I thought I had done everything, or did I (again) forget something ?

Michael.

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.

------------------------------------------------------------------------

_______________________________________________
fpc-devel maillist  -  fpc-devel@lists.freepascal.org
http://lists.freepascal.org/mailman/listinfo/fpc-devel

_______________________________________________
fpc-devel maillist  -  fpc-devel@lists.freepascal.org
http://lists.freepascal.org/mailman/listinfo/fpc-devel