ShowMessage when open Form (Designer Time)

Question

I want show a notify (eg. ShowMessage) when a programmer open a Form in designer time.
Is possible? How?
Thanks.

PS: Delphi XE7 / VCL

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I have a project with more than 700 form's, but when the programmer opens a specific one, I want to be given a notification (eg ShowMessage) stating that there are, for example, comments at the beginning of the .pas file.

This should happen in any form.

Answer 1

If you want to do this for ANY form, there is a straightforward way to do it. (As per David Heffernan's comment, whether your user will thank you it another matter, but anyway ...)

It involves installing a package in the IDE which installs an object which implements the IDesignNotification interface.

To use, create a new form and add a TMemo to it, rename the form to DesignNotifierForm, save it to disk then copy the code below into it. Then create a new package and add the unit to it. Then compile and install the package. In older Delphi versions like D7, there is an install button in the Package Editor, whereas in more recent versions like D10 Seattle, you go to View | Project manager in the IDE, then right-click on the BPL file in the pop-up and select Install from the pop-up context menu.

As you can see, in addition to the form, the unit declares a notifier object, TDesignNotification which implements an interface so that it can be registered with the IDE designer and receive notifications from it. The only one which is of interest from your pov is DesignerOpened, which iswhere you can call ShowMessage or do whatever you want.

The TDesignNotifierForm is included mainly as a simple way to experiment with & observe the notifications that the TDesignNotification receives, The TDesignNotification would work perfectly well without the form, though.

Btw, you might want to take a look at the ToolsAPI.Pas unit, which contains a host of interfaces which can be used to interact with the IDE.

unit DesignNotifierFormu;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ExtCtrls, StdCtrls, TypInfo, ToolsApi, DesignIntf;

type
  TDesignNotifierForm = class(TForm)
    Memo1: TMemo;
    Panel1: TPanel;
  private
  public
    procedure Log(const Title, Msg : String);
  end;

  TDesignNotification = class(TInterfacedObject, IDesignNotification)
    F : TDesignNotifierForm;
    procedure ItemDeleted(const ADesigner: IDesigner; AItem: TPersistent);
    procedure ItemInserted(const ADesigner: IDesigner; AItem: TPersistent);
    procedure ItemsModified(const ADesigner: IDesigner);
    procedure SelectionChanged(const ADesigner: IDesigner;
      const ASelection: IDesignerSelections);
    procedure DesignerOpened(const ADesigner: IDesigner; AResurrecting: Boolean);
    procedure DesignerClosed(const ADesigner: IDesigner; AGoingDormant: Boolean);
    constructor Create;
    destructor Destroy; override;
  end;

var
  DesignNotification : TDesignNotification;

implementation

{$R *.dfm}

procedure SetUp;
begin
  DesignNotification := TDesignNotification.Create;
  RegisterDesignNotification(DesignNotification);
end;

procedure TDesignNotifierForm.Log(const Title, Msg: String);
begin
  Memo1.Lines.Add(Title + ': ' + Msg);
end;

constructor TDesignNotification.Create;
begin
  inherited Create;
  F := TDesignNotifierForm.Create(Nil);
  F.Show;
  F.Log('Event', 'Notifier created');
end;

procedure TDesignNotification.DesignerClosed(const ADesigner: IDesigner;
  AGoingDormant: Boolean);
begin

end;

procedure TDesignNotification.DesignerOpened(const ADesigner: IDesigner;
  AResurrecting: Boolean);
var
  C : TComponent;
  Msg : String;
begin
  C := ADesigner.Root;
  if C <> Nil then begin
    Msg := C.ClassName;
    //  At this point, you can call ShowMessage or whatever you like
    ShowMessage(Msg);
  end
  else
    Msg := 'no root';
  F.Log('Designed Opened', Msg);
end;

destructor TDesignNotification.Destroy;
begin
  F.Close;
  F.Free;
  inherited;
end;

procedure TDesignNotification.ItemDeleted(const ADesigner: IDesigner;
  AItem: TPersistent);
begin

end;

procedure TDesignNotification.ItemInserted(const ADesigner: IDesigner;
  AItem: TPersistent);
begin

end;

procedure TDesignNotification.ItemsModified(const ADesigner: IDesigner);
begin

end;

procedure TDesignNotification.SelectionChanged(const ADesigner: IDesigner;
  const ASelection: IDesignerSelections);
begin
end;


initialization
  SetUp;
finalization
  if DesignNotification <> Nil then begin
    UnRegisterDesignNotification(DesignNotification);
    //  Evidently the following is superfluous and results in a double-free  DesignNotification.Free;
  end;
end.

I want to be given a notification (eg ShowMessage) stating that there are, for example, comments at the beginning of the .pas file.

Well, the code above shows you how to provide some kind of event when a form is opened. How to do something like extract comments at the beginning of the file is a different technical problem really, and should be raised in a new question if you get stuck trying to do it.

Btw, one of the comments on your q pointed you in the direction of a code snippet by Dr Bob. That's fine as far as showing the technique is concerned, but would only do what you want if you were to install your own form in a package.