//подгружаем данные
 private void LoadData()
 {
     var queryLocation=(from c in context.Locations
                       where c.LocationName==prevLocation
                       select c).FirstOrDefault();
     if (queryLocation != null)
         currentLocation = queryLocation;
 }
 //подтверждение операции
 private void buttonOK_Click(object sender, EventArgs e)
 {
     if (CheckData())
     {
         switch (mode)
         {
             case WindowsMode.ADD:
                 currentLocation = new Location();
                 currentLocation.LocationName = textBoxLocation.Text.Trim();
                 context.Locations.Add(currentLocation);
                 context.SaveChanges();
                 break;
             case WindowsMode.EDIT:
                 currentLocation.LocationName = textBoxLocation.Text.Trim();
                 context.Entry(currentLocation).State = System.Data.Entity.EntityState.Modified;
                 context.SaveChanges();
                 break;
         }
         this.DialogResult = DialogResult.OK;
     }
     else
     {
         switch (validateInput)
         {
             case LocationInputValidate.LocationEmpty: NotifyWarning("Location input is empty!"); break;
             case LocationInputValidate.LocationNotUnique: NotifyWarning("Location is not unique!"); break;
         }
     }
 }