TCustomAction.Execute Method

Responds when a client control "fires".

Pascal

function Execute: Boolean; override;

C++

virtual __fastcall Boolean Execute();

Description

Execute is called automatically when a client control "fires" (for example, when the user clicks a button or selects a menu item). It returns true if an event handler is found to handle the action, false if there was no event handler or if the action was not enabled.

Execute first ensures that the action is updated. Then, if the Enabled property is true, it attempts to handle the action by generating an OnExecute event on the action list that contains this action (if the action belongs to an action list). If the action list's OnExecute event handler does not handle the action, Execute generates an OnActionExecute event on the application itself. If neither the action list nor the application handles the action in response to these events, Execute generates an OnExecute event on itself. If this action has no OnExecute event handler, Execute instructs the application to locate the current target control and call the ExecuteTarget method, which is the mechanism by which predefined action classes perform their function.

C++ Examples:

Copy Code

/*
This code displays a Save Picture dialog box with the
TBitmap default extension that is added automatically to
files that are given no extension. Confirm that the
bitmap file has been saved under the filename and path
specified.
*/
void __fastcall TForm1::Button1Click(TObject *Sender)
{
  AnsiString NewFileName, OldFileName;
  TFileStream *NewFile, *OldFile;
  SavePictureDialog1->DefaultExt = GraphicExtension(__classid(Graphics::TBitmap));
  SavePictureDialog1->Filter = GraphicFilter(__classid(Graphics::TBitmap));
  OldFileName = "factory.bmp";
  if (SavePictureDialog1->Execute())
  {
    NewFileName = SavePictureDialog1->FileName;
    OldFile = new TFileStream(OldFileName, (fmOpenRead | fmShareDenyWrite));
    try
    {
      NewFile = new TFileStream(NewFileName, (fmCreate | fmShareDenyRead));  
      try
      {
        NewFile->CopyFrom(OldFile, OldFile->Size);
      }
      __finally
      {
        FreeAndNil(NewFile);
      };
    }
    __finally
    {
      FreeAndNil(OldFile);
    };
  };
}

void __fastcall TForm1::FormCreate(TObject *Sender)
{
  Image1->Picture->LoadFromFile("../factory.bmp");
}

Delphi Examples:

Copy Code

{
This code displays a Save Picture dialog box with the
TBitmap default extension that is added automatically to
files that are given no extension. Confirm that the
bitmap file has been saved under the filename and path
specified.
}
procedure TForm1.Button1Click(Sender: TObject);
var NewFileName, OldFileName: string;
    NewFile, OldFile: TFileStream;
begin
  SavePictureDialog1.DefaultExt := GraphicExtension(TBitmap);
  SavePictureDialog1.Filter := GraphicFilter(TBitmap);
  OldFileName := 'factory.bmp';
  if SavePictureDialog1.Execute then
  begin
    NewFileName := SavePictureDialog1.FileName;
    OldFile := TFileStream.Create(
      OldFileName, fmOpenRead or fmShareDenyWrite);
    try
      NewFile := TFileStream.Create(
        NewFileName, fmCreate or fmShareDenyRead);
      try
        NewFile.CopyFrom(OldFile, OldFile.Size);
      finally
        FreeAndNil(NewFile);
      end;
    finally
      FreeAndNil(OldFile);
    end;
  end;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  Image1.Picture.LoadFromFile('factory.bmp');
end;