我是ASP.NET MVC的新手。我熟悉其他MVC框架，如Rails和PHP MVC FM。
我需要每天在ASP.NET MVC中运行一次函数 - 我应该怎么做？我想要这个函数来更新数据库。
在Linux中，我可以将URL放到Cron每天访问一次的服务器上，但我不知道在Windows中执行此操作的最佳方法。
答案 0 :(得分：0)
基本上你需要在web.config文件中添加两个AppSettings：
<appSettings>
.
<add key="TimerStartTime" value="09:00:00 PM"/>
<add key="TimerIntervalInMilliseconds" value="3000000"/>
</appSettings>
然后，在Global.asax.cs文件中修改并添加：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Http;
using System.Web.Mvc;
using System.Web.Optimization;
using System.Web.Routing;
// Added the following for the timer related code
using System.Diagnostics;
using System.Timers;
using System.Web.Configuration;
namespace TestVSOnline01
{
public class MvcApplication : System.Web.HttpApplication
{
// Added this class visible variable to hold the timer interval so it's not gotten from the
// web.config file on each Elapsed event of the timer
private static double TimerIntervalInMilliseconds =
Convert.ToDouble(WebConfigurationManager.AppSettings["TimerIntervalInMilliseconds"]);
protected void Application_Start()
{
AreaRegistration.RegisterAllAreas();
GlobalConfiguration.Configure(WebApiConfig.Register);
FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
RouteConfig.RegisterRoutes(RouteTable.Routes);
BundleConfig.RegisterBundles(BundleTable.Bundles);
// Added the following within the Application_Start() procedure:
// *******************************************************************************************
// The values used in this example will cause your processes to run sometime
// between 09:00:00 PM and 09:05:00 PM, with the timer Elapsed event being raised
// every 300000ms (5 minutes)
//
// The following AppSettings were added to Web.config:
// TimerStartTime
// TimerIntervalInMilliseconds
// You can use a simple text editor to change your start time and/or timer interval without
// having to modify your code, recompile, and republish it.
//
// The shorter the interval, then smaller the time window in which the processes will run, but
// the more frequently all of this code and event firing is happening. But you could set the
// interval to 1000ms and have you events run right at the time specified.
//
// !!! NOTE: The web.config file is not designed for constant updates. When an ASP.NET
// !!! application launches a watch is put on the web.config file. ASP.NET will detect if the
// !!! web.config changes while the application is running. When ASP.NET detects a change it
// !!! will spin up a new version of the application with the new settings in effect. Any in
// !!! process information, such as data kept in Session, Application, and Cache will be lost
// !!! (assuming session state is InProc and not using a state server or database).
// !!! (Source: http://odetocode.com/Articles/345.aspx)
//
// *******************************************************************************************
// The Debug.WriteLine calls are for watching the progress in the Output Window
// in Visual Studio - Remove or comment out if you like
Debug.WriteLine(string.Concat("Application_Start Called: ", DateTime.Now.ToString()));
// This will raise the Elapsed event every 'x' millisceonds (whatever you set in the
// Web.Config file for the added TimerIntervalInMilliseconds AppSetting
Timer timer = new Timer(TimerIntervalInMilliseconds);
timer.Enabled = true;
// Setup Event Handler for Timer Elapsed Event
timer.Elapsed += new ElapsedEventHandler(timer_Elapsed);
timer.Start();
}
// Added the following procedure:
static void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
{
// Get the TimerStartTime web.config value
DateTime MyScheduledRunTime = DateTime.Parse(WebConfigurationManager.AppSettings["TimerStartTime"]);
// Get the current system time
DateTime CurrentSystemTime = DateTime.Now;
Debug.WriteLine(string.Concat("Timer Event Handler Called: ", CurrentSystemTime.ToString()));
// This makes sure your code will only run once within the time frame of (Start Time) to
// (Start Time+Interval). The timer's interval and this (Start Time+Interval) must stay in sync
// or your code may not run, could run once, or may run multiple times per day.
DateTime LatestRunTime = MyScheduledRunTime.AddMilliseconds(TimerIntervalInMilliseconds);
// If within the (Start Time) to (Start Time+Interval) time frame - run the processes
if ((CurrentSystemTime.CompareTo(MyScheduledRunTime) >= 0) && (CurrentSystemTime.CompareTo(LatestRunTime) <= 0))
{
Debug.WriteLine(String.Concat("Timer Event Handling MyScheduledRunTime Actions: ", DateTime.Now.ToString()));
// RUN YOUR PROCESSES HERE
}
}
}
}
清理干净，非常简单。下面的代码只是您需要添加到Global.asax.cs文件的简化版本（不要忘记添加web.config appsettings）：
// Added the following for the timer related code
using System.Diagnostics; // Can remove this reference if you remove all the Debug.Writeline entries
using System.Timers;
using System.Web.Configuration;
// Add the following to the top of the main class, outside of any subroutines:
private static double TimerIntervalInMilliseconds = Convert.ToDouble(WebConfigurationManager.AppSettings["TimerIntervalInMilliseconds"]);
// Add the following to the end of the Application_Start() subroutine:
Timer timer = new Timer(TimerIntervalInMilliseconds);
timer.Enabled = true;
timer.Elapsed += new ElapsedEventHandler(timer_Elapsed);
timer.Start();
// Added the following procedure:
static void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
{
DateTime MyScheduledRunTime = DateTime.Parse(WebConfigurationManager.AppSettings["TimerStartTime"]);
DateTime CurrentSystemTime = DateTime.Now;
DateTime LatestRunTime = MyScheduledRunTime.AddMilliseconds(TimerIntervalInMilliseconds);
if ((CurrentSystemTime.CompareTo(MyScheduledRunTime) >= 0) && (CurrentSystemTime.CompareTo(LatestRunTime) <= 0))
{
// RUN YOUR PROCESSES HERE
}
}