How to dynamically create customized TabSheet runtime

Question

I would like to create a TTabsheet which has to be create during run time. The TTabSheet has several components, but all of these components will be identical on every tab. Is it possible to create a "type" variable which will create these tabs every time?

Thanks

Sounds like you need a TTabControl instead – David Heffernan Nov 28 '14 at 13:46 — David Heffernan, Nov 28 '14 at 13:46

Ari0nhh · Accepted Answer · 2014-11-28T13:49:39.153

2

Yes. You could create inherited class from TTabSheet

TCustomTabSheet = class(TTabSheet)
public
  constructor Create(AOwner : TComponent); override;
public
   FTestButton : TButton;
end;

constructor TCustomTabSheet.Create(AOwner : TComponent);
begin
  inherited Create(AOwner);
  FTestButton := TButton.Create(Self);
  FTestButton.Parent := Self;
  FTestButton.Left := 1;
  FTestButton.Top := 1;
  FTestButton.Width := 20;
  FTestButton.Heigth := 10;
  FTestButton.Caption := 'Cool button!';
  FTestButton.Name := 'TestButton';
end;

You could also create a frame (TFrame) with your custom controls in design time and host it instances to all new tabs.

edited Nov 28 '14 at 13:49

answered Nov 28 '14 at 12:51

Ari0nhh

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Thank you very much. I am still quite a novice when it comes to programming :) Is it possible to change the name of some components afterwards? And what does the "inherited Create" command do? – Marnu123 Nov 28 '14 at 13:05
Updated example a little. inherited calls default TTabSheet constructor to ensure correct control initialization. – Ari0nhh Nov 28 '14 at 13:12
1

Why do you care about the names of the controls? – David Heffernan Nov 28 '14 at 13:45
1

@Ari You need to set the control Parent – David Heffernan Nov 28 '14 at 13:46
It is in order to free the components afterwards. But thanks – Marnu123 Nov 28 '14 at 15:24
This seems overly complicated. It's all well and good to create a subclass from TTabSheet, but you have to add it to the TPageControl, which isn't obvious from the above example. Usually this is done at design time, but you can't do that with the derived class. – David Schwartz Nov 28 '14 at 18:49

David Schwartz · Answer 2 · 2014-11-28T19:08:59.193

Just for the fun of it, here's a snippet of code I use periodically to add a tabsheet to a TPageControl that has a TMemo on it. This would be used, for example, if you've got a form that is used for editing text files. You'd call this to add a new tab with the filename as caption, then load the memo's .Line property from the file's contents.

function TMy_form.add_ts_mmo( ntbk : TPageControl; caption : string ) : TTabSheet;
var mmo : TMemo;
begin
  Result := TTabSheet.Create(self);
  Result.PageControl := ntbk;
  Result.Caption := caption;
  mmo := TMemo.Create(self);
  Result.Tag := Integer(mmo);
  mmo.Parent := Result;
  mmo.Font.Name := 'Courier New';
  mmo.Font.Size := 10;
  mmo.Align := alClient;
  mmo.ScrollBars := ssBoth;
  mmo.WordWrap := true;
end;

You call it by giving it the PageControl you want it to be added to, and a caption that's used in the tab.

var
  ts : TTabSheet;
. . .
  ts := add_ts_mmo( myPageControl, ExtractFileName( text_file_nm ) );

Note that I save the new memo's pointer in ts.Tag so I can easily get to it later on through a cast.

TMemo(ts.Tag).Lines.LoadFromFile( text_file_nm );

No subclassing is required. You can create any other components you might want on the tabsheet as well, after the Result.Caption := caption line. Just be sure to set their .Parent property to Result.

The PageControl can be created either at design time or run-time.

How to dynamically create customized TabSheet runtime

2 Answers2

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