Menu funktionalität ohne MainMenu

[Sir Rufo]

Eine weitere Alternative ist das Versenden einer Nachricht

Delphi-Quellcode:

unit UserCommand;

interface

uses
  System.Messaging;

type
{$SCOPEDENUMS ON}
  TUserCommand = ( Print, Save, SaveAs );

  TUserCommandMessage = class( TMessage )
  private
    FCommand: TUserCommand;
    FIsQuery: Boolean;
    FHandled: Boolean;
  public
    constructor Create( ACommand : TUserCommand; AIsQuery : Boolean = False );
    property Command: TUserCommand read FCommand;
    property IsQuery: Boolean read FIsQuery;
    property Handled: Boolean read FHandled write FHandled;
  end;

implementation

{ TUserCommandMessage }

constructor TUserCommandMessage.Create(ACommand: TUserCommand;
  AIsQuery: Boolean);
begin
  inherited Create;
  FCommand := ACommand;
  FIsQuery := AIsQuery;
  FHandled := False;
end;

end.

die von der Action verschickt wird

Delphi-Quellcode:

procedure TMainForm.FilePrint1Execute( Sender: TObject );
begin
  TMessageManager.DefaultManager.SendMessage( Self, TUserCommandMessage.Create( TUserCommand.Print ), True );
end;

procedure TMainForm.FilePrint1Update( Sender: TObject );
var
  LCmd: TUserCommandMessage;
begin
  LCmd := TUserCommandMessage.Create( TUserCommand.Print, True );
  try
    TMessageManager.DefaultManager.SendMessage( Self, LCmd, False );
    TAction( Sender ).Enabled := LCmd.Handled;
  finally
    LCmd.Free;
  end;
end;

und von den Empfängern entsprechend behandelt wird

Delphi-Quellcode:

procedure TMDIChild.AfterConstruction;
begin
  inherited;
  TMessageManager.DefaultManager.SubscribeToMessage( TUserCommandMessage, HandleUserCommand );
end;

procedure TMDIChild.BeforeDestruction;
begin
  TMessageManager.DefaultManager.UnSubscribe( TUserCommandMessage, HandleUserCommand );
  inherited;
end;

procedure TMDIChild.HandleUserCommand( const Sender: TObject; const M: TMessage );
var
  LCmd: TUserCommandMessage absolute M;
begin
  if not Self.Active then
    Exit;

  case LCmd.Command of
    TUserCommand.Print:
      if LCmd.IsQuery then
        LCmd.Handled := ( Memo1.Text <> '' );
      else
        // Dokument drucken
    TUserCommand.Save:
      ;
    TUserCommand.SaveAs:
      ;
  end;

end;

Das geht dann ohne Interfaces ...