Delphi: How to embed a VCL form into a panel - user-interface

Question

The form "Form1" contains a panel.
On this panel we want to embed a second form "Form2".
But not only the components should be embedded, but also the functionality.
I am using a VCL form.
I have already tried this tutorial on this page.
How to put a form in panel
unit parent;
interface
uses
Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.ExtCtrls, child;
type
TForm1 = class(TForm)
Panel1: TPanel;
procedure FormCreate(Sender: TObject);
private
{ Private-Deklarationen }
public
{ Public-Deklarationen }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.FormCreate(Sender: TObject);
begin
Form2 := TForm2.Create(Panel1);
with Form2 do
Name := 'MyForm';
Parent := Panel1;
Width := 500;
Height := 500;
Top := 10;
Left := 10;
Show;
end;
end.
unit child;
interface
uses
Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls;
type
TForm2 = class(TForm)
btnCalc: TButton;
Edit1: TEdit;
Edit2: TEdit;
Edit3: TEdit;
Label1: TLabel;
procedure btnCalcClick(Sender: TObject);
private
{ Private-Deklarationen }
public
{ Public-Deklarationen }
end;
var
Form2: TForm2;
implementation
{$R *.dfm}
procedure TForm2.btnCalcClick(Sender: TObject);
begin
edit3.Text:=edit1.Text+edit2.Text;
end;
end.
The form is not displayed at startup and Form2 is not embedded in Form1.

Answer 1

For future reference, when you post a question about code, copy - paste actual code and inform possible shown errors.
In the first edition of your question, your code recreated Form1 within the constructor of the same form. After some time the program fails with an out of resources error.
In your second edition, where you corrected erroneous references of Form1 to Form2 your code is still missing a begin .. end pair around the properties you want to set after with Form2 do. This error leads to a stack overflow because you are setting Form1 parent to Panel1 which is a child of Form1, iow a chicken - egg dilemma.
Because you did not mention either of these errors, one can only conclude that your code is different from what you have posted, or, you think that error messages are not important. WRONG! So, please take the lesson and pay attention to post actual code and inform about any error messages.
Also, if your question is about appearance of a form, post the .dfm file content.
With the following code Form2 is shown embedded in the Panel1 of Form1 (I removed the width and height settings to keep the image smaller):
procedure TForm1.FormCreate(Sender: TObject);
begin
Form2 := TForm2.Create(Panel1);
with Form2 do
begin
Name := 'MyForm';
Parent := Panel1;
Top := 10;
Left := 10;
Show;
end;
end;
The Top and Left properties don't look as expected. That is because the default value of the TForm.Position property is poDefaultPosOnly which means that the form bypasses the Top and Left settings and leaves it to the OS to decide on the location. However since the form is given a parent that doesn't apply either and the form is just placed at position 0,0. Add the line regarding position property below (or set it in Form2 designer).
...
Parent := Panel1;
Position := poDesigned; // add this line
BorderStyle := bsNone; // and this for a better embedded appearance
Top := 10;
...
The result is now: