c#比较时间

private DateTime startTime ;
void Page_Init(Object sender, EventArgs e) 
{ 
　　startTime = DateTime.Now;
}

protected override void Render(HtmlTextWriter writer) 
{ 
　　base.Render(writer);

　　DateTime endTime = DateTime.Now; 
　　System.TimeSpan mySpan = endTime-startTime;
　　string strall = mySpan.Seconds.ToString();

　　Response.Write("总加载时间=" + strall); 
}