private void removeBtn_Click(object sender, EventArgs e)
 {
     try
     {
         if (controller.RemoveItem(int.Parse(itemIdTB.Text)))
         {
             updateMsg("Item successfully deleted.", false);
         }
         else
         {
             updateMsg("Item does not exist.", true);
         }
     }
     catch (FormatException ex)
     {
         updateMsg("Invalid Format", true);
     }
 }
 private void removeBtn_Click(object sender, EventArgs e)
 {
     try
     {
         int id = int.Parse(borrowerIdTB.Text);
         if (controller.RemoveItem(id))
         {
             updateMsg((controller.GetBorrower(id) is Model.Student ? "Student" : "Teacher") + " successfully deleted.", false);
         }
         else
         {
             updateMsg("Borrower does not exist.", true);
         }
     }
     catch (FormatException ex)
     {
         updateMsg("Invalid Format", true);
     }
 }