public void AddIncomeValue()
 {
     if ((SelectedAvailableIncome != null) && (IncomeValueValue > 0))
     {
         var incomeValue = Budget.AddIncomeValue(SelectedAvailableIncome, IncomeValueValue, IncomeValueDate, IncomeValueDescription);
         SaveRevenue(incomeValue);
         IncomeValueValue        = 0;
         IncomeValueDescription  = string.Empty;
         SelectedAvailableIncome = null;
     }
 }