private void btnReturn_Click(object sender, EventArgs e)
        {
            int       rentNumber;
            int       objectID;
            DateTime  returnDate = DateTime.Today;
            bool      res        = int.TryParse(txtRentNumber.Text, out rentNumber);
            RequestDB req        = new RequestDB();

            objectID = req.ReqGetObjectNumber(rentNumber);
            Employees.ReturnObject(objectID);
            MessageBox.Show("L'objet a correctement été retourné");
            ActiveForm.Close();
        }