protected void Page_Load(object sender, EventArgs e)
        {
            if (DB == null)
            {
                DB = DBHandler.Instance;
            }

            if (Session["selectedTask"] != null)
            {
                int taskindex = (int)Session["selectedTask"];
                selectedTask = DB.db.TTasks.FirstOrDefault(t => t.ID == taskindex);

                TaskCreatedByLabel.Text    = "Created by " + DB.getUserByID((int)selectedTask.CreatorID).Username;
                TaskLastEditedByLabel.Text = "Last edited by " + DB.getUserByID((int)selectedTask.LastEditorID).Username + " on " + selectedTask.LastEditedDate;
                StartDateEndDateLabel.Text = "Should be done in: " + selectedTask.StartDate + " - " + selectedTask.EndDate;
                TextOfTaskLabel.Text       = selectedTask.TextOfTask;

                if (Session["SharingTaskError"] != null)
                {
                    SharingTasksError.Text = (string)Session["SharingTaskError"];
                }
                else
                {
                    SharingTasksError.Text = String.Empty;
                }
            }
        }
        protected void SubmitChanges_Click(object sender, EventArgs e)
        {
            TTask taskToEdit = new TTask();

            if (Session["TaskToEdit"] != null)
            {
                taskToEdit = DB.getTaskByID((int)Session["TaskToEdit"]);
            }
            else
            {
                taskToEdit.ID = DB.getFreeIDForTask();
            }

            taskToEdit.NameOfTask = NameOfTheTaskTB.Text;
            taskToEdit.TextOfTask = TextOFTheTaskTB.Text;

            DateTime newStartDate = new DateTime(
                Int32.Parse(StartTaskYear.Items[StartTaskYear.SelectedIndex].Text),
                Int32.Parse(StartTaskMonth.Items[StartTaskMonth.SelectedIndex].Text),
                Int32.Parse(StartTaskDay.Items[StartTaskDay.SelectedIndex].Text));

            taskToEdit.StartDate = newStartDate;

            DateTime newEndDate = new DateTime(
                Int32.Parse(EndTaskYear.Items[EndTaskYear.SelectedIndex].Text),
                Int32.Parse(EndTaskMonth.Items[EndTaskMonth.SelectedIndex].Text),
                Int32.Parse(EndTaskDay.Items[EndTaskDay.SelectedIndex].Text));

            taskToEdit.EndDate = newEndDate;

            taskToEdit.LastEditorID   = ((User)Session["LoggerUser"]).ID;
            taskToEdit.LastEditedDate = DateTime.Now;

            taskToEdit.AddNewUser((int)taskToEdit.LastEditorID);

            if (Session["TaskToEdit"] == null)
            {
                taskToEdit.CreatorID = taskToEdit.LastEditorID;
                DB.db.TTasks.Add(taskToEdit);
            }

            DB.db.SaveChanges();

            if (Session["TaskToEdit"] == null)
            {
                DB.getUserByID((int)taskToEdit.LastEditorID).AddNewTask(taskToEdit.ID, (int)taskToEdit.CreatorID);
            }

            Session["TaskToEdit"] = null;

            Response.Redirect("Default.aspx");
        }