計算兩日期時間差異天數TimeSpan Subtract

         Dim sd As Date = TextBox_sd1.Text
        Dim ed As Date = TextBox_ed1.Text
        '計算兩日期時間差
        Dim vd As TimeSpan = ed.Subtract(sd)
       '差異天數
        Dim my_vd As Integer = vd.TotalDays