Create an exact copy of TPanel on Delphi5

Question

I have a TPanel pnlMain, where several dynamic TPanels are created (and pnlMain is their Parent) according to user actions, data validations, etc. Every panel contains one colored grid full of strings. Apart from panels, there are some open source arrows components and a picture. Whole bunch of stuff.

Now I want user to be able to print this panel (I asked how to do it on this question), but before printing, user must be presented with a new form, containing copy of pnlMain. On this form user has to do some changes, add few components and then print his customized copy of pnlMain. After printing user will close this form and return to original form with original pnlMain. And – as you can guess – original pnlMain must remain intact.

So is there any clever way to copy whole TPanel and it’s contents? I know I can make it manually iterating through pnlMain.Controls list.

Answer 1

Code based as iterating on child controls, but not bad in anyway ;-)

procedure TForm1.btn1Click(Sender: TObject);

    function CloneComponent(AAncestor: TComponent): TComponent;
      var
        XMemoryStream: TMemoryStream;
        XTempName: string;
      begin
        Result:=nil;
        if not Assigned(AAncestor) then
          exit;
        XMemoryStream:=TMemoryStream.Create;
        try
          XTempName:=AAncestor.Name;
          AAncestor.Name:='clone_' + XTempName;
          XMemoryStream.WriteComponent(AAncestor);
          AAncestor.Name:=XTempName;
          XMemoryStream.Position:=0;
          Result:=TComponentClass(AAncestor.ClassType).Create(AAncestor.Owner);
          if AAncestor is TControl then TControl(Result).Parent:=TControl(AAncestor).Parent;
          XMemoryStream.ReadComponent(Result);
        finally
          XMemoryStream.Free;
        end;
      end;

    var
      aPanel: TPanel;
      Ctrl, Ctrl_: TComponent;
      i: integer;
    begin
      //handle the Control (here Panel1) itself first
      TComponent(aPanel) := CloneComponent(pnl1);
      with aPanel do
      begin
        Left := 400;
        Top := 80;
      end;

      //now handle the childcontrols
      for i:= 0 to pnl1.ControlCount-1 do begin
        Ctrl := TComponent(pnl1.Controls[i]);
        Ctrl_ := CloneComponent(Ctrl);
        TControl(Ctrl_).Parent := aPanel;
        TControl(Ctrl_).Left := TControl(Ctrl).Left;
        TControl(Ctrl_).top := TControl(Ctrl).top;
      end;
    end;

code from Delphi3000 article

Answer 2

I'd do it by using RTTI to copy all the properties. You'd still have to iterate over all the controls, but when you need to set up the property values, RTTI can help automate the process. You can get an example towards the bottom of this article, where you'll find a link to some helper code, including a CopyObject routine.

Answer 3

Too much code... ObjectBinaryToText and ObjectTextToBinary do the job nicely using streaming. Delphi 7 have a code example, don't know 2009 (or 2006, never bothered to look) still have it. See D5 help file for those functions (don't have d5 available here).