Question

We have an application that have many components on the forms (panels, tabs, edits, comboboxes, etc…). But depending on the user profile, most of them could be filled automatically and/or not be visible. So, users could do their work faster.

The question: Is there any easier way to create, position, change ownership etc, at runtime? I would like to create 2 .dfm files for a given unit and then have something to tell the application what .dfm to use. Like: “Hey! User is advanced, use the Unit1Advanced.dfm!” A working example would be nice. I would like to use that in Delphi 7 too, but it has to work at least in Delphi XE.

What I know that exist till now:

1. ComponentsToCode function from GExperts can create code from a given component as gabr pointed in this answer.
2. I could create 2 forms and create the desired one at runtime. But that means one additional .pas file to each additional .dfm file. This would be harder to maintain.
3. This answer seems to give a hint. But I am not used to TReader and TWriter classes…

Answer 1

Warning: This answer is for completeness sake to the question and is only for experimental purposes. It should never be used in real world scenarios.

You want two separate form definition files for only one source code file.

The key is to make use of the CreateNew constructor. To quote the documentation on it:

Use CreateNew instead of Create to create a form without using the associated .DFM file to initialize it.

1. First, write your advanced form:

   unit Advanced;
   
   interface
   
   uses
     Classes, Controls, Forms, StdCtrls;
   
   type
     TAdvancedForm = class(TForm)
       StandardGroupBox: TGroupBox;
         StandardButton: TButton;
       AdvancedGroupBox: TGroupBox;
         AdvancedButton: TButton;
       procedure StandardButtonClick(Sender: TObject);
       procedure AdvancedButtonClick(Sender: TObject);
     end;
   
   implementation
   
   {$R *.dfm}
   
   procedure TAdvancedForm.StandardButtonClick(Sender: TObject);
   begin
     Caption := Caption + ' Button1Click';
   end;
   
   procedure TAdvancedForm.AdvancedButtonClick(Sender: TObject);
   begin
     Caption := Caption + ' Button2Click';
   end;
   
   end.
   

2. Build your app, and copy Advanced.dfm to Standard.dfm.

3. Open Standard.dfm in a text editor and remove the advanced components (in this case the advanced group box containing a button), and rename the form and form type to (T)StandardForm:

   object StandardForm: TStandardForm
     ...
     object StandardGroupBox: TGroupBox
       ...
       object StandardButton: TButton
         ...
       end
     end
   end
   

4. Add the resource for the standard form to Advanced.pas:

   {$R *.dfm}
   {$R Standard.dfm}
   

5. And now with the following code, you can open both form definitions for the same source file:

   uses
     Advanced;
   
   procedure TForm1.OpenAdvancedFormClick(Sender: TObject);
   var
     Form: TAdvancedForm;
   begin
     Form := TAdvancedForm.Create(Application);
     Form.Show;
   end;
   
   procedure TForm1.OpenStandardFormClick(Sender: TObject);
   var
   {
     Form: TAdvancedForm; // This is tricky! The form we are about to create has
                          // no AdvancedGroupBox nor AdvancedButton, so make sure
                          // you are not calling it with code completion.
     Form: TStandardForm; // Compiler has no knowledge of TStandardForm!
   }
     Form: TForm;         // So declare your form as TForm!
   begin
     // But create it as TAdvancedForm, otherwise components will not be found!
     Form := TAdvancedForm.CreateNew(Application);
     ReadComponentRes('TStandardForm', Form);
     Form.Show;
   end;