private void grdArticoli_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
       {
            grdArticoli.EditingControl.KeyPress -= new KeyPressEventHandler(EditingControl_KeyPress);
            grdArticoli.EditingControl.KeyPress += new KeyPressEventHandler(EditingControl_KeyPress);
        }

        void EditingControl_KeyPress(object sender, KeyPressEventArgs e)
        {
            try
            {
                Char oChar_Period = char.Parse(".");
                Char oChar_Comma = char.Parse(",");
                if (e.KeyChar == oChar_Period)
                    e.KeyChar = oChar_Comma;
            }
            catch { }
        }