private void button3_Click(object sender, EventArgs e)
 {
     try
     {
         EquipmentServices catService = new EquipmentServices();
         Food f = catService.GetById(id);
         f.Id   = id;
         f.Name = textBox5.Text;
         f.Cost = Convert.ToDouble(textBox4.Text);
         int result = catService.update(f);
         if (result > 0)
         {
             MessageBox.Show("Food updated.");
             UpdateGridView();
         }
         else
         {
             MessageBox.Show("Error");
         }
     }
     catch (Exception)
     {
         MessageBox.Show("Error!");
     }
 }