private void enterToSystem_Click(object sender, RoutedEventArgs e)
      {
          try
          {
              BE.Mother temp = null;
              temp = bl.searchMother(this.idBox.Text);

              if (temp == null)
              {
                  throw(new Exception("no exist"));
              }

              if (temp.Password != this.passwordBox.Password)
              {
                  throw (new Exception("Incorrect password"));
              }

              existMother exstMom = new existMother(temp);
              exstMom.Show();
              this.idBox.Clear();
              this.passwordBox.Clear();
          }
          catch (Exception p)
          {
              MessageBox.Show(p.Message);
          }
      }