Problem with selection markes in Delphi IDE for Controls with SubControls

[Tom Mueller 5]

Hallo all

 

I have a control (TWinControl) that contains an other control (TPanel) and registered it in a package (see demo code in the attachment),

 

First Problem: When selecting the control in the IDE, the selection markers are only partially visible.

Second Problem: When selecting more than one control, no selection markers are visible at all.

 

Is this a known problem and are there any solutions for it?

 

Thanks

Tom

 

TestSelectMarker.7z

[Tom Mueller 5]

To handle this, I could register my own IOTANotifier with a IOTAWizard to get notified when the control is selected, and then draw the markers manually.

I found some notifiers for the code editor like TNTACodeEditorNotifier but could not find a proper notifier for the form designer.

If anyone has undertaken a similar task, your assistance would be greatly appreciated.

 

[Pat Foley 53]

On 2/20/2025 at 2:15 AM, Tom Mueller said:

I have a control (TWinControl) that contains an other control (TPanel)

You need to add the paint event to draw the control in the IDE plus WMSIZE to allow sizing of controls being drawn.  Changing to descend from Tpanel allows working control base to add control to.  Later the control can be switched to TCustomControl or TWinControl. 

 

unit uTestSelectMarker;

interface

uses
 Classes, Vcl.Controls, Vcl.ExtCtrls, Winapi.Messages;

type

  TTestSelectMarker = class(TPanel)  //change to TcustomControl or TWinControl
  private
    FPanel: TPanel;
  protected
    procedure Paint; override;
    procedure WMSIZE(var message:TWMSIZE); message WM_SIZE;
  public
    constructor Create(AOwner: TComponent); override;
  end;

procedure Register;

implementation

uses
  Graphics;

constructor TTestSelectMarker.Create(AOwner: TComponent);
begin
  inherited;// Create(AOwner);
 Color := clBtnFace;

  FPanel:= TPanel.Create(self);
//  FPanel.SetSubComponent(True); // Uwe mentioned this in SO post 
  FPanel.Parent:= self;
  FPanel.BevelOuter:= bvNone;
  FPanel.Color:= clCream;
  FPanel.Visible := True;
end;

procedure Register;
begin
  RegisterComponents('Test',  [TTestSelectMarker]);
end;

procedure TTestSelectMarker.Paint;
begin
  inherited;
  FPanel.Caption := Name;
end;

procedure TTestSelectMarker.WMSIZE(var message: TWMSIZE);
begin
  FPanel.setbounds(10,10,Width- 2 * 10, Height - 2 * 10);
end;

end.

 

[Tom Mueller 5]

Thank you for your response.

 

I noticed that you reduce the size of the sub-control to display the markers correctly.

This works but unfortunately, this approach prevents the sub-control from being displayed at its desired size.

 

In my case, the sub-control can be of type TEdit, TCheckBox, TComboBox, TDateTime or TMemo, and it is essential that they maintain their correct size at design time.

 

By reducing the sub-control size, a correct form layout is not possible, and it would look like:

 

Or, is there a way to reduce the size of the sub-component only when more than one control is selected?

 

Edited 14 hours ago by Tom Mueller

[Pat Foley 53]

6 hours ago, Tom Mueller said:

I noticed that you reduce the size of the sub-control to display the markers correctly.

I should have included this

procedure TTestSelectMarker.WMSIZE(var message: TWMSIZE);
begin
 // FPanel.setbounds(10,10,Width- 2 * 10, Height - 2 * 10);
  Fpanel.Align := alClient;
end;

 

 

[Tom Mueller 5]

Thanks for your effort but you can see the partial markers only because the panel has a border of 1 pixel (due to BevelOuter=bvRaise).

Set BevelOuter=bvNone the markers are hidden completely again.

[Pat Foley 53]

To reveal the markers add to source or set in Object Inspector

BorderWidth = 5