DBCtrlGrid with a Lookup ComboBox

Question

has anyone managed to get a DBLookupComboBox to work with a DBCtrlGrid?

a pre filled in DBComboBox works ok, but it dose not work to well for lookup tables;

delphi 7

Answer 1

I just added a TDBLookupCombo to a TDBCtrlGrid. When I tried to set the ListSource, I got the error:

Operation not allowed in a DBCtrlGrid.

Therefore it appears that this is explicitly forbidden in Delphi and so you won't be able to do it.

Answer 2

Well, I don't understand why it is forbidden action in Delphi, but i've managed to create my own lookup-combo-box component with csReplicatable flag in ComponentStyle and it works!

Its not thoroughly tested, but in my app it works without problems.

Here is source - check it out

Answer 3

Being quite reticent to alter/maintain altered VCL/RTL code, I found another way. Declare the following in the Interface of your unit:

interface

uses ... ;

type Tdbp = class(TDBCtrlGrid); type tdbl = class(TDBLookupControl);

type TForm4 = class(TForm) ... DBCtrlGrid1: TDBCtrlGrid; ... private ... function FindLCB(DataFieldName: String): TDBLookupComboBox; procedure FixDBLookupDataLinks; public ... end;

...and in your implementation:

---

implementation

procedure TForm4.FormCreate(Sender: TObject); begin ... DBCtrlGrid1.DataSource := DataSource1; FixDBLookupDataLinks; end;

procedure TForm4.FixDBLookupDataLinks; var lcb: TDBLookupComboBox; I,n: Integer; MyDataLink: TDataLink; ctl: TControl; dbp: Tdbctrlpanel; begin dbp := Tdbp(DBControlGrid1).Panel; for n := 0 to Pred(dbp.ControlCount) do begin ctl := dbp.Controls[n]; if ctl.ClassType = TDBLookupComboBox then begin lcb := TDBLookupComboBox(ctl); lcb.ControlStyle := lcb.ControlStyle + [csReplicatable]; TDBL(lcb).ListLink.DataSourceFixed := False; for I := 0 to Pred(lcb.ControlCount) do begin if lcb.Controls[I] is TPopupDataList then begin TDBL(lcb).ListLink.DataSourceFixed := False; TDBL(lcb).DataLink.DataSourceFixed := False; MyDataLink := TDataLink(lcb.Controls[I].Perform(CM_GETDATALINK, 0, 0)); if MyDataLink <> nil then MyDataLink.DataSourceFixed := False; MyDataLink.DataSource := nil; end; end; end; end; end;

function TForm4.FindLCB(DataFieldName: String): TDBLookupComboBox; var i: Integer; begin Result := Nil; for i := 0 to Pred(ControlCount) do if Controls[i].ClassType = TDBLookupComboBox then if TDBLookupComboBox(Controls[i]).DataField = DataFieldName then begin Result := TDBLookupComboBox(Controls[i]); Break; end; end;