[SOLVED] In DBGrid not visible result in lookup field (LookupResultField)

[xcod]

I created a Firebird database with two tables
I use IBConnection of SQLdb
to form two DBGrid and DBLookupComboBox
created a lookup field in SQLQuery for DBGrid, and set the properties in DBLookupComboBox
DBGrid in the lookup value in a field is selected and modified, but not displayed
in DBLookupComboBox everything is working fine
I create a test project and attached

Please, help..where I made ​​a mistake?
Sorry for my bad english...

[ludob]

When you set StringField1.LookupCache to true it works.  This looks like a bug. I'll investigate further.

[xcod]

Thank's for a quick reply.
I set StringField1.LookupCache to true and it's work fine.
Please post to bugtracker if it's bug.

Sorry for my English..

[ludob]

Please post to bugtracker if it's bug.

The problem is that TCustomBufDataset.Lookup is not implemented and TDataset.Lookup returns Null. TSQLQuery is a descendant of  TCustomBufDataset.
The issue and patch to implement TCustomBufDataset.Lookup can be found at http://bugs.freepascal.org/view.php?id=22099

[BigChimp]

Nice as usual. Hope it gets committed soon...

[xcod]

Thanks, it's fixed.

[xinyiman]

I'm trying to do what you have done to code, but it does not work. I enclose my source, can anyone help me solve?

[nomorelogic]

hi, try using this code instead of the one on your FormCreate method

Code: [Select]

procedure TForm1.FormCreate(Sender: TObject);
var Temf:TStringField;
begin

          {dichiaro la struttura del dataset virtuale}
          VDSet_Chiavi.FieldDefs.Add('Id',ftInteger);
          VDSet_Chiavi.FieldDefs.Add('Chiave',ftString,50);
          VDSet_Chiavi.CreateDataset;{creo il dataset virtuale con la struttura sopra dichiarata}
          VDSet_Chiavi.Open; {apro la connessione al dataset virtuale}
          VDSet_Chiavi.Append; {dico che voglio accodare dei dati al dataset virtuale}
          VDSet_Chiavi.Fields[0].Value:=1;
          VDSet_Chiavi.Fields[1].Value:='Carmen';
          VDSet_Chiavi.Post; {applico l'accodamento}
          VDSet_Chiavi.Append;{dico che voglio accodare dei dati al dataset virtuale}
          VDSet_Chiavi.Fields[0].Value:=2;
          VDSet_Chiavi.Fields[1].Value:='Ti';
          VDSet_Chiavi.Post; {applico l'accodamento}
          VDSet_Chiavi.Append;{dico che voglio accodare dei dati al dataset virtuale}
          VDSet_Chiavi.Fields[0].Value:=3;
          VDSet_Chiavi.Fields[1].Value:='Amo';
          VDSet_Chiavi.Post; {applico l'accodamento}

          {dichiaro la struttura del dataset virtuale}
          VDSet_Principale.FieldDefs.Add('Id_Chiave',ftInteger);
          VDSet_Principale.FieldDefs.Add('Utente',ftString,50);
          VDSet_Principale.FieldDefs.Add('NewLookUpField',ftString,50);
          VDSet_Principale.CreateDataset;{creo il dataset virtuale con la struttura sopra dichiarata}

          Temf := TStringField(VDSet_Principale.Fields.FindField('NewLookUpField'));

          Temf.FieldKind := fkLookup;
          Temf.LookupDataSet:=Self.VDSet_Chiavi;
          Temf.LookupCache:=FALSE;
          Temf.LookupKeyFields:='ID';
          Temf.LookupResultField:='CHIAVE';
          Temf.ReadOnly:=FALSE;
          Temf.ProviderFlags:=[pfInUpdate, pfInWhere];
          Temf.Required:=FALSE;
          Temf.KeyFields:='Id_Chiave';

          VDSet_Principale.Open; {apro la connessione al dataset virtuale}
          VDSet_Principale.Append; {dico che voglio accodare dei dati al dataset virtuale}
          VDSet_Principale.Fields[0].Value:=1;
          VDSet_Principale.Fields[1].Value:='root';
          VDSet_Principale.Post; {applico l'accodamento}
          VDSet_Principale.Append;{dico che voglio accodare dei dati al dataset virtuale}
          VDSet_Principale.Fields[0].Value:=2;
          VDSet_Principale.Fields[1].Value:='root';
          VDSet_Principale.Post; {applico l'accodamento}
          VDSet_Principale.Append;{dico che voglio accodare dei dati al dataset virtuale}
          VDSet_Principale.Fields[0].Value:=3;
          VDSet_Principale.Fields[1].Value:='root';
          VDSet_Principale.Post; {applico l'accodamento}


          Self.DBGrid2.Columns[0].Width:=50;
          Self.DBGrid2.Columns[1].Width:=100;
          Self.DBGrid2.Columns[2].Width:=100;


          exit;


          VDSet_Principale.Fields[2].FieldKind:=fkLookUp;
          VDSet_Principale.Fields[2].DataSet := Self.VDSet_Principale;
          VDSet_Principale.Fields[2].LookupDataSet := Self.VDSet_Chiavi;
          VDSet_Principale.Fields[2].KeyFields := 'ID';
          VDSet_Principale.Fields[2].LookupKeyFields := 'Chiave';
          VDSet_Principale.Fields[2].LookupResultField := 'ID_Chiave';
          VDSet_Principale.Fields[2].LookupCache := true;


          Self.DBLookupComboBox1.Visible:=FALSE;
          Self.DBLookupComboBox1.LookupCache:=TRUE;
          Self.DBLookupComboBox1.DataSource:=Self.DS_Principale;
          Self.DBLookupComboBox1.DataField:='Id_Chiave';
          Self.DBLookupComboBox1.ListSource:=Self.DS_Chiavi;
          Self.DBLookupComboBox1.KeyField:='Id';
          Self.DBLookupComboBox1.ListField:='Chiave';

end;


Edit:
if you don't need a TStringField you can avoid typecast changing the declaration of Temf in:

Code: [Select]

var Temf:TField;
and, changing the line

Code: [Select]

Temf := TStringField(VDSet_Principale.Fields.FindField('NewLookUpField'));with following

Code: [Select]

Temf := VDSet_Principale.Fields.FindField('NewLookUpField');

[xinyiman]

Thank you very much 

[xinyiman]

They also do not understand why at the start of my program which I am attaching does not auto populate the field NewLookUpField. You know tell me why, would he do if the fields were indexed.


Is a BUG?!

[nomorelogic]

I think an Index cannot be the solution.
Running as downloaded from previous message, the 3rd column is empty for all records (-> lookup field seems it is not a "lookup field").

You can replace the block of code after comment " //INSERISCO UN PO' DI DATI NEL DATASET VIRTUALE PRINCIPALE"
with following block.
After replace, you can run and this is what we can expect at startup from a lookup field.
Surely this is not the solution.

Code: [Select]

procedure TForm1.FormCreate(Sender: TObject);
var
  Temf:TField;
  CurrKey: integer;
begin
...

     //INSERISCO UN PO' DI DATI NEL DATASET VIRTUALE PRINCIPALE
     VDSet_Principale.Open; {apro la connessione al dataset virtuale}

     CurrKey := 1;
     VDSet_Principale.AppendRecord([CurrKey,'root', VDSet_Chiavi.Lookup('ID', CurrKey, 'Chiave') ]);

     CurrKey := 2;
     VDSet_Principale.AppendRecord([2,'toor', VDSet_Chiavi.Lookup('ID', CurrKey, 'Chiave') ]);

     CurrKey := 3;
     VDSet_Principale.AppendRecord([3,'pippo', VDSet_Chiavi.Lookup('ID', CurrKey, 'Chiave')]);
...