private void buttonAddContract_Click(object sender, RoutedEventArgs e)
 {
     try
     {
         contract.nameChild  = (bl.getChild(contract.idChild)).fullName;
         contract.nameNanny  = nanny.fullName;
         contract.isContract = true;
         if (contract.isHour)
         {
             contract.salaryAgreed = contract.salaryPerHour;
         }
         else
         {
             contract.salaryAgreed = contract.salaryPerMonth;
         }
         bl.addContract(contract);
         MessageBox.Show("חוזה נחתם בהצלחה");
         dataGridDetalis.ItemsSource       = null;
         comboBoxChooseChild.SelectedIndex = -1;
         comboBoxChooseMom.SelectedIndex   = -1;
         contract = new BE.Contract();
         addContractTab.DataContext = contract;
     }
     catch (Exception Ex)
     {
         MessageBox.Show(Ex.Message);
     }
 }