private void Button_PostAnnouncement(object sender, RoutedEventArgs e)
{
var announcement = new BusinessObjects.Announcement()
{
Title = TitleAnnouncemenTextBox.Text,
Comments = CommentsTextBox.Text
};
var teacher = new TeacherBll();
if (teacher.AddAnouncement(announcement))
{
MessageBox.Show("Announcement Added");
}
}