/// <summary>
        /// Відкриття файлу БД
        /// </summary>
        private void OpenFile()
        {
            // block other menu
            BlockMenu(true);

            if (openFileD.ShowDialog() == DialogResult.OK)
            {
                this.path     = Path.GetDirectoryName(openFileD.FileName);
                this.filename = Path.GetFileNameWithoutExtension(openFileD.FileName);

                db?.Dispose();
                //using (db = new LesApp0Context(path, filename))
                //{
                db = new LesApp0Context(path, filename);

                db.Audiences.Load();

                // load data
                LoadDBOnForm(db);
                //}
            }

            // finish
            statusLabel.Text = "Finish loading";
            Cursor           = Cursors.Default;

            // unblock
            BlockMenu(false);
        }
        /// <summary>
        /// Створення файла БД
        /// </summary>
        private void CreateFile()
        {
            // block other menu
            BlockMenu(true);

#if false
            if (folderBrowser.ShowDialog() == DialogResult.OK)
            {
                this.path = folderBrowser.SelectedPath;

                // choose directory and save data there
                AppDomain.CurrentDomain.SetData("DataDirectory", path);

                db.Dispose();

                db = new LesApp0Context();

                //using (db = new LesApp0Context())
                //{
                db.Audiences.Load();
                db.SaveChanges();

                // load data
                LoadDBOnForm(db);
                //}
            }
#endif
            if (saveFileD.ShowDialog() == DialogResult.OK)
            {
                this.path     = Path.GetDirectoryName(saveFileD.FileName);
                this.filename = Path.GetFileNameWithoutExtension(saveFileD.FileName);

                db?.Dispose();

                db = new LesApp0Context(path, filename);
                db.Audiences.Load();
                db.SaveChanges();

                LoadDBOnForm(db);
            }

            // finish
            statusLabel.Text = "Finish creating";
            Cursor           = Cursors.Default;

            // unblock
            BlockMenu(false);
        }