How to add additional properties to objects of the same class and make the handler one for all?

Question

Delphi

There is a DBGrid on the form.
It has an OnDataHintShow event.
I described it. But I realized that this code will be repeated for many Grids, so I decided to put it in a separate procedure and pass parameters there.
When I described a couple more handlers, I realized that the parameters remain the same as in the previous one, but again, the code will be repeated and you need to take it out.
Therefore, I created a class:
TDynamicGrid = class(DBGridEh)
Described its properties and procedure, for example ShowPanel (which pops up on OnDataHintShow).
There were questions:
1. How to make, that Grid (DBGridEh) located on the form, became TDynamicGrid.
It is configured, fitted, designed, and I would not want to create it programmatically and prescribe all the parameters.
If in the description of the form, I change the class to the required one in the code of this grid - Delphik swears, says that it is incorrectly defined, but the error can be ignored. Then everything works, but! The error "Exception EInvalidPointer"
2 pops up. All the same, you have to enter the grid and register a call to this procedure in the OnDataHintShow event.
Is it possible to somehow write an event handler in a class so that it would act by default for all objects of this class?

unit DynamicGrid;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.UITypes, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, CompoMansEh, Vcl.ExtCtrls,
  PivotGridToolsEh, Data.DB, EhLibVCL, GridsEh, DBAxisGridsEh, DBVertGridsEh,
  Vcl.StdCtrls, Vcl.DBCtrls, Data.Win.ADODB, DBGridEhGrouping, ToolCtrlsEh,
  DBGridEhToolCtrls, DynVarsEh, DBGridEh, System.ImageList, Vcl.ImgList;


type
  TDynamicGrid = class(TDBGridEh)
    private
      PanelOnGrid: TPanel;
      HighlightColor: TColor;
      GlobalArrSList: TStringList;
    public
      property GridPanel : TPanel read PanelOnGrid write PanelOnGrid;
      property HColor: TColor read HighlightColor write HighlightColor;
      property GlobalArr: TStringList read GlobalArrSList write GlobalArrSList;

      procedure ShowPanel(Cell: TGridCoord);
      constructor Create(AOwner : TComponent); override;
      destructor Destroy; override;
 end;

implementation

procedure TDynamicGrid.ShowPanel(Cell: TGridCoord);
var
 rect: TRect;
 rectX, rectY : extended;
 Name, ID: string;
begin
  rect := self.CellRect(Cell.X, Cell.Y);

    rectX := Rect.TopLeft.X + Rect.Width;
    rectY := Rect.TopLeft.Y + Rect.Height/2 + Rect.Height - 1;

   if Cell.Y = self.Row then
    self.PanelOnGrid.Color := self.HColor
   else
    self.PanelOnGrid.Color := clWhite;

    self.PanelOnGrid.Left := trunc(rectX - self.PanelOnGrid.Width/2);
    self.PanelOnGrid.Top := trunc(rectY);

    self.PanelOnGrid.Visible := true;

    Name := self.DataSource.DataSet.FieldByName('Name').AsString;
      ID := self.DataSource.DataSet.FieldByName('ID').AsString;

    self.GlobalArr.Values['ID'] := ID;
    self.GlobalArr.Values['Name'] := Name;

    TForm(self.Parent).caption := 'Справочник: ' + Name;
end;

constructor TDynamicGrid.Create(AOwner: TComponent);
begin
  inherited;
end;

destructor TDynamicGrid.Destroy;
begin
  inherited;
end;

end.

So. DBGrid has a column, and it has an OnDataHintShow event.
Delphi handler is called like this: TForm.GridNameColumns0DataHintShow.
where 0 is apparently the column number, GridName is the name of the Grid.
I want this event to automatically call the ShowPanel procedure. No matter what you have to write by hand.

Answer 1

DBGridEh and everything about it is also written in dfm. You can try editing it by hand. It might roll.
Well, for good, you need to complete the TDynamicGrid as a component in order to work with it in the usual way in design time.