Hi Brad,
I asked "Do you also need to add these fields to a query?"
If the ClientDataset is tied to a Query and not used as an in-memory dataset
then you must first add it to the query before adding it to the
ClientDataset.
I know this works because we build our queries and clientdatasets on the fly
as needed in out program.
Here is three actual procedures that we use to create 3 different query
fields (Integer, Date and String):
{---------------------------------------------------------------------------
--
Procedure: AddQueryStringField
Author: Michael Tuttle
Date: 2001
Purpose:
----------------------------------------------------------------------------
-}
procedure TdtmAccountRem.AddQueryStringField(Query: TIBQuery; FldName:
String;
FldKind: TFieldKind; FieldSize: Integer);
var
fldString: TStringField;
begin
fldString := TStringField.Create(Query);
with fldString do
begin
FieldName := FldName;
FieldKind := FldKind;
DisplayLabel := FieldName;
Size := FieldSize;
DataSet := Query;
Name := Query.Name + FieldName;
ProviderFlags := [];
end;
with Query.FieldDefs do
begin
Add(fldString.Name, ftString, FieldSize, False);
Update;
end;
end;
{---------------------------------------------------------------------------
--
Procedure: AddQueryDateField
Author: Michael Tuttle
Date: 2001
Purpose:
----------------------------------------------------------------------------
-}
procedure TdtmAccountRem.AddQueryDateField(Query: TIBQuery; FldName: String;
FldKind: TFieldKind);
var
fldDate: TDateField;
begin
fldDate := TDateField.Create(Query);
with fldDate do
begin
FieldName := FldName;
FieldKind := FldKind;
DisplayLabel := FieldName;
DataSet := Query;
Name := Query.Name + FieldName;
ProviderFlags := [];
end;
with Query.FieldDefs do
begin
Add(fldDate.Name, ftDate, 0, False);
Update;
end;
end;
{---------------------------------------------------------------------------
--
Procedure: AddQueryIntegerField
Author: Michael Tuttle
Date: 2001
Purpose:
----------------------------------------------------------------------------
-}
procedure TdtmAccountRem.AddQueryIntegerField(Query: TIBQuery; FldName:
String;
FldKind: TFieldKind);
var
fldIntegerField: TIntegerField;
begin
fldIntegerField := TIntegerField.Create(Query);
with fldIntegerField do
begin
FieldName := FldName;
FieldKind := FldKind;
DisplayLabel := FieldName;
DataSet := Query;
Name := Query.Name + FieldName;
ProviderFlags := [];
end;
with Query.FieldDefs do
begin
Add(fldIntegerField.Name, ftInteger, 0, False);
Update;
end;
end;
Here is an example call:
AddQueryIntegerField(qryAddress, PERSON_ID, fkData);
Again create the query field first then the clientdataset field. We do it
all the time.
Good luck and let me know how this works out for you.
Mike
----- Original Message -----
From: "Gies,Brad" <[EMAIL PROTECTED]>
To: "Delphi-Talk Discussion List" <[email protected]>
Sent: Monday, October 10, 2005 7:43 PM
Subject: RE: Adding a field to a ClientDataSet at runtime
> Mike,
>
> Are you sure about that? Reading the help for update sounds like it
> looks at the fields and updates the definitions according to the fields,
> not the fields according to the definitions. I'll try it anyway though.
>
> I have tried just creating a new TField Object and adding it to the
> ClientDataSet using the Fields.Add method, but when trying to add a
> value to the field it couldn't find it. I'm not sure why.
>
>
> Sincerely,
>
> Brad Gies
> -------------------------------------
> NLM Software
> Southfield, MI, USA
> -------------------------------------
>
>
>
>
>
> > -----Original Message-----
> > From: [EMAIL PROTECTED] [mailto:delphi-talk-
> > [EMAIL PROTECTED] On Behalf Of M Tuttle (KS)
> > Sent: Monday, October 10, 2005 7:58 PM
> > To: Delphi-Talk Discussion List
> > Subject: Re: Adding a field to a ClientDataSet at runtime
> >
> > Something like this. Do you also need to add these field to a query?
> >
> > Procedure SomeProcedure
> > var
> > fldStringField: TStringField;
> > fldIntegerField: TIntegerField;
> > begin
> >
> > with cdsAddress do
> > begin
> > //* Add the persistent field
> > with FieldDefs do
> > begin
> > fldIntegerField := TIntegerField.Create(cdsAddress);
> > with fldIntegerField do
> > begin
> > FieldName := 'FIELD_NAME';
> > DisplayLabel := FieldName;
> > DataSet := cdsAddress;
> > Name := cdsAddress.Name + FieldName;
> > cdsAddress.FieldDefs.Add(fldIntegerField.Name,
> > ftInteger,
> > 0, False);
> > end;
> >
> > fldStringField := TStringField.Create(cdsAddress);
> > with fldStringField do
> > begin
> > FieldName := 'ANOTHER_FIELD_NAME';
> > DisplayLabel := FieldName;
> > DataSet := cdsAddress;
> > Name := cdsAddress.Name + FieldName;
> > cdsAddress.FieldDefs.Add(fldStringField.Name,
> ftString,
> > 1,
> > False);
> > end;
> >
> > //* Update the field defs
> > Update;
> > end;
> > end;
> > end:
> >
> > ----- Original Message -----
> > From: "Gies,Brad" <[EMAIL PROTECTED]>
> > To: "Delphi-Talk Discussion List" <[email protected]>
> > Sent: Monday, October 10, 2005 6:44 PM
> > Subject: Adding a field to a ClientDataSet at runtime
> >
> >
> > >
> > > Does anyone know how to add a new field to a ClientDataSet after the
> > > DataSet is already created? Is it possible?
> > >
> > > Sincerely,
> > >
> > > Brad Gies
> > > -------------------------------------
> > > NLM Software
> > > Southfield, MI, USA
> > > -------------------------------------
> > >
> > >
> > >
> > >
> > >
> > >
> > >
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