How to replace a TDBNavigator with a TSpeedButton? - delphi

Question

I did:
procedure TForm1.SpeedButton1Click(Sender: TObject);
begin
DataTable.qOrders.Next;
end;
It works, but the problem is when I click the button to reach the last record, the button is not disabled, like in a TDBNavigator.
How did I make the TSpeedButton disable and enable automatically like the TDBNavigator does?

Answer 1

Drop a TActionList onto your form and add the standard dataset actions to it. Connect these actions to your dataset and your speedbuttons to the appropriate actions. These standard actions will handle the enable state according to the current dataset state.

Answer 2

Here is a simple solution, that works perfectly for me.
I have a form (frmMain), dataset (dsWork), datasource (srcWork), grid and two speedbuttons (btnNext and btnPrior). The important part is in "OnDataChange" event of TDataSource. Here is the source code:
unit MainForm;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, Grids, DBGrids, DB, DBTables, StdCtrls, ExtCtrls;
type
TfrmMain = class(TForm)
btnNext: TButton;
srcWork: TDataSource;
dsWork: TTable;
btnPrior: TButton;
grdWork: TDBGrid;
procedure btnNextClick(Sender: TObject);
procedure btnPriorClick(Sender: TObject);
procedure srcWorkDataChange(Sender: TObject; Field: TField);
private
{ Private declarations }
public
{ Public declarations }
end;
var
frmMain: TfrmMain;
implementation
{$R *.dfm}
procedure TfrmMain.btnNextClick(Sender: TObject);
begin
if not dsWork.Eof then dsWork.Next;
end;
procedure TfrmMain.btnPriorClick(Sender: TObject);
begin
if not dsWork.Bof then dsWork.Prior;
end;
procedure TfrmMain.srcWorkDataChange(Sender: TObject; Field: TField);
begin
btnNext.Enabled := not dsWork.Eof;
btnPrior.Enabled := not dsWork.Bof;
end;
end.