在C#里关于定时器类有3个：System.Windows.Forms.Timer类、System.Threading.Timer类和System.Timers.Timer类。
System.Windows.Forms.Timer是应用于WinForm中的，它是通过Windows消息机制实现的，类似于VB或Delphi中的Timer控件，内部使用API SetTimer实现的。它的主要缺点是计时不精确，而且必须有消息循环，Console Application(控制台应用程序)无法使用。
System.Timers.Timer和System.Threading.Timer非常类似，它们是通过.NET Thread Pool实现轻量、精确的计时，对应用程序、消息没有特别的要求。System.Timers.Timer还可以应用于WinForm，完全取代上面的Timer控件。它们的缺点是不支持直接的拖放，需要手工编码。
public int wrong = 0;
System.Timers.Timer time = new System.Timers.Timer();
private void begin_Click(object sender, EventArgs e)
{
if (action.Text == "启动监测")
{
action.Text = "停止监测";
label2.Text = "已启动"; if (time.Interval.ToString() == "100") // The default value of interval is 100s.
{
time.Elapsed += new ElapsedEventHandler(TimeEvent);
time.Interval = 1000;
}
time.Enabled = true;
}
else
{
action.Text = "启动监测";
label2.Text = "已停止"; time.Enabled = false;
} } private static void TimeEvent(object source, ElapsedEventArgs e)
{
int tsec = e.SignalTime.Second;
int isec = 10;
if (tsec == isec) //it will be activated at 10s of every minutes.
{
if (!Check("http://www.test.com"))
{
string smtp_server="192.168.8.1";
int port = 25;
string mail_from = "test_from@163.com";
string sender="test";
string mail_to = "test_to@163.com";
string receiver="adminer";
string subject = "The site is run out exception on " + DateTime.Now.ToString("yyyyMMddhhmmss");
string body = "The site can not open on " + DateTime.Now.ToString() + ",please check it !";
try
{
SendEmail(smtp_server, port, mail_from, sender, mail_to, receiver, subject, body);
}
catch(Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}
} private static bool Check(string urlStr)
{
HttpWebRequest myWebRequest = null;
try
{
myWebRequest = (HttpWebRequest)WebRequest.Create(urlStr);
HttpWebResponse res = (HttpWebResponse)myWebRequest.GetResponse();
if (res.StatusCode == HttpStatusCode.OK)
{
res.Close();
return true;
}
else
{
res.Close();
return false;
}
}
catch (Exception)
{
return false;
}
} public static void SendEmail(string smtp_server, int port, string mail_from, string sender, string mail_to, string receiver, string subject, string body)
{
MailAddress from = new MailAddress(mail_from, sender);
MailAddress to = new MailAddress(mail_to, receiver);
MailMessage message = new MailMessage(from, to);
message.BodyEncoding = Encoding.UTF8;
message.IsBodyHtml = true;
message.Subject = subject;
message.Body = body; SmtpClient client = new SmtpClient(smtp_server, port);
//SmtpClient client = new SmtpClient(smtp_server); // Add credentials if the SMTP server requires them.
client.Credentials = CredentialCache.DefaultNetworkCredentials;
client.Send(message);
}