private void Button_Click(object sender, RoutedEventArgs e)
        {
            ProjectData project = new ProjectData(projectId++);
            DateTime    now     = DateTime.Now;

            project.Data.Add(new DataItem(1, now, now.AddMinutes(5)));
            project.Data.Add(DataItem.Create(2, now.AddMinutes(30), now.AddMinutes(55), DataItem.Create(3, now.AddMinutes(40), now.AddMinutes(45))));
            this.Projects.Add(project);
        }
        private void Modify_Click(object sender, RoutedEventArgs e)
        {
            ProjectData project = this.Projects[projectId - 1];

            project.Data.Add(DataItem.Create(1, project.EndPoint.Value.AddMinutes(20), null));
        }