MVC Update

In the real world, which I obviously can't post here, I have a problem where the result of the validation request does three things;

1) Validates the input values
2) Returns other information based on the inputs (i.e. Other client, stock details)
3) Set whether a specific field input is valid or not.

More MVC!

A client search from would look like this ..

type
  TForm3 = class(TForm, IObserver)
    Button1: TButton;
    Edit1: TEdit;
    ListBox1: TListBox;
    Button2: TButton;
    Button3: TButton;
    procedure FormCreate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
    procedure UpdateView (obj : TObject);
  end;

...

procedure TForm3.Button1Click(Sender: TObject);
var
  c : TCommand;
  o : TCommandParam;

begin
  c := TCommand.Create ('SEARCH');

  o := TCommandParam.Create;
  o.Name := edit1.Text;

  c.AddParam(o);

  Controller.DoCommand(c);
end;

procedure TForm3.Button2Click(Sender: TObject);
begin
  ModalResult := mrOK;
end;

procedure TForm3.Button3Click(Sender: TObject);
begin
  ModalResult := mrCancel;
end;

procedure TForm3.FormCreate(Sender: TObject);
begin
  Controller.AddView (self);
end;

procedure TForm3.UpdateView (obj : TObject);
var
  val : String;

begin
  // Update the view here
  if ((obj as TDomainModel).ClientSearchResult <> nil) then
  begin
    for val in (obj as TDomainModel).ClientSearchResult do
    begin
      ListBox1.AddItem(val, nil);
    end;
  end;
end;

I have merge the View classes with the actual form, in order to make the code relationships a little clearer.

I'm really happy with all of the, and I think it will be applicable for the requirements I have at work.