C# 時間對比函數

  protected void BtDuring_Click(object sender, EventArgs e)
    {
        DateTime dtTemp = new DateTime(1984, 10, 7);
        DateTime dtTemp70 = dtTemp.AddYears(70);
        DateTime dtTemp80 = dtTemp.AddYears(80);
        DateTime dtTemp90 = dtTemp.AddYears(90);
        DateTime dtTemp100 = dtTemp.AddYears(100);

        Response.Write(GetPassingDay(dtTemp, DateTime.Now)+"<br>");
        Response.Write(GetPassingDay(dtTemp, dtTemp100)+"<br>");
        Response.Write(GetPassingDay(DateTime.Now, dtTemp70) + "<br>");
        Response.Write(GetPassingDay(DateTime.Now, dtTemp80) + "<br>");
        Response.Write(GetPassingDay(DateTime.Now, dtTemp90) + "<br>");
        Response.Write(GetPassingDay(DateTime.Now, dtTemp100) + "<br>");
        Response.Write(GetPassingDay(DateTime.Now, dtTemp100) + "<br>");
    }

    public int GetPassingDay(DateTime dtStart,DateTime dtEnd)
    {
        DateTime dtTemp = dtStart;
        DateTime dtNow = dtEnd;
        TimeSpan ts = dtNow - dtTemp;
        return (int)Math.Round(ts.TotalDays);
    }