C#中如何计算时间差?

C#中怎么计算两时间相差多少。计算2个时间之间的差,可以计算到时分秒!

<1>

label1.Text = "2004-1-1 15:36:05";

label2.Text = "2004-3-1 20:16:35";

DateTime d1 =new DateTime(2004,1,1,15,36,05);

DateTime d2 =new DateTime(2004,3,1,20,16,35);

TimeSpan d3 = d2.Subtract(d1);

label3.Text = "相差:"

+d3.Days.ToString()+"天"

+d3.Hours.ToString()+"小时"

+d3.Minutes.ToString()+"分钟"

+d3.Seconds.ToString()+"秒";

<2>

PRotected void Page_Load(object sender, EventArgs e)

{

if (!IsPostBack)

{

DateTime dt1 = Convert.ToDateTime("2009-07-31 00:00:00");

DateTime dt2 = Convert.ToDateTime("2009-08-02 00:00:00");

this.Label1.Text = this.DateDiff(dt1,dt2);

}

}

private string DateDiff(DateTime DateTime1, DateTime DateTime2)

{

string dateDiff = null;

try

{

TimeSpan ts1 = new TimeSpan(DateTime1.Ticks);

TimeSpan ts2 = new TimeSpan(DateTime2.Ticks);

TimeSpan ts = ts1.Subtract(ts2).Duration();

dateDiff = ts.Days.ToString() + "天" + ts.Hours.ToString() + "小时" + ts.Minutes.ToString() + "分钟" + ts.Seconds.ToString() + "秒";

}

catch

{ }

return dateDiff;

}

<3>

string st1 = "14:16";

string st2 = "14:14";

DateTime dt1 = Convert.ToDateTime(st1);

DateTime dt2 = Convert.ToDateTime(st2);

int result = DateTime.Compare(dt1, dt2);

如果st1的时间大于st2 , result = 1

如果相等就等于0，

如果小于就是-1