窗口服务行为怪异 [英] windows service strange behavior

问题描述

我实现Windows服务事件日志和 FileSystemWatcher的这会在特定的目录更改并写入信息到 MyLog 。

I implemented windows service with eventLog and FileSystemWatcher that looks for changes in specific directory and writes messages into MyLog.

奇怪的事1：结果
我通过installUtil.exe安装（因为VS2012没有安装模板），并在某些情况下，当我去服务，开始我得到的服务：

strange thing 1:
I install it via installUtil.exe (since the VS2012 doesn't have installer templates) and in some situations when I go to "Services" and start the service I get:

本地计算机上的[服务名称]服务启动，然后停止。如果他们不被其他服务或程序使用的一些服务自动停止。

The [service name] service on local computer started and then stopped. Some Services stop automatically if they are not in use by another services or programs.

我已经看过的这个问题。从这个职位2 answeres为什么它可以是这样：

I've already seen this question. 2 answeres from this post why it can be so:

1）没有螺纹的OnStart开始（）法。结果
我使用设计，并设置大部分属性在属性窗口中，我从来没有手动启动任何线程，但在某些情况下，一切工作，所以我觉得这是不是这样的。

1) There is no thread starting in OnStart() method.
I use the designer and set most of the properties in the Properties window and I never started any thread manually, but in some cases everything was working, so I think this is not the case.

2）例外的OnStart（）方法occures。我认为这不是因为我不更改代码的情况。我刚刚卸载，构建并重新安装相同的服务，并在运行某些情况下，有些不是。

2) An exception occures in OnStart() method. I think it's not the case cause I don't change the code. I just uninstall, build and install again the same service and in some cases it runs, in some not.

当我被卡住了mabby这个东西我注意到2小时该事件日志的来源属性是太长：FilesMonitoringServices。我把它改成MonitorSource一切都开始工作。比我重新安装了它cauple的时候，得到了同样的警告如上述。我又换了来源属性，现在服务运行。结果
这是第一次奇怪的事情。

When I was stuck for mabby 2 hours with this thing I noticed that the Source property of eventLog is too long: "FilesMonitoringServices". I changed it to "MonitorSource" and everything started to work. Than I reinstalled it cauple of times and got the same warning as the above. I changed the Source property again and now the service runs.
This is the first strange thing.

奇怪的事2：更糟。即使运行时，它仅记录的OnStart（）和调用OnStop（）的方法，我的意思是FileSystemWatcher的事件处理程序从未excutes 。这很奇怪，因为今天我重新安装了这个服务mabby一百次和3次是工作，但之后我再次重新安装它，它采空。我没有任何改变reinstallations是在之间的代码。

strange thing 2: worse. Even if it runs it logs only OnStart() and OnStop() methods, I mean the fileSystemWatcher event handler never excutes. It is strange because today I reinstalled this service mabby hundred times and 3 times it was working but after I reinstalled it once again it stoped. And I haven't changed the code between the reinstallations at all.

下面是我的课（MonitoringService）继承 ServiceBase 的方法和构造器：

Here is the methods and constructor from my class (MonitoringService) that inherits ServiceBase:

public MonitoringService()
    {
        InitializeComponent();

        if (!EventLog.SourceExists(eventLog.Source))
        {
            EventLog.CreateEventSource(eventLog.Source, eventLog.Log);
        }
        // haven't changed it between the reinstallations
        fileWatcher.Path = @"path";                
    }

protected override void OnStart(string[] args)
    {
        fileWatcher.EnableRaisingEvents = true;
        eventLog.WriteEntry("start", EventLogEntryType.Information);
        base.OnStart(args);
    }

    protected override void OnStop()
    {
        fileWatcher.EnableRaisingEvents = false;
        fileWatcher.Dispose();
        eventLog.WriteEntry("stop", EventLogEntryType.Information);
        base.OnStop();
    }

和文件系统观察事件处理程序：

And file system watcher event handler:

private void fileSystemWatcher1_Changed(object sender, FileSystemEventArgs e)
    {
        using (var conn = new SqlConnection(GetConnectionString()))
        {
            conn.Open();
            var productId = Convert.ToInt32(Regex.Match(e.Name, @"\d+").Value);
            const string cmd = "UPDATE Products SET ImageModifiedDate=@date WHERE ProductId=@productId";
            using (var command = new SqlCommand(cmd, conn))
            {
                command.Parameters.AddWithValue("@productId", productId);
                command.Parameters.AddWithValue("@date", DateTime.Now);
                command.ExecuteNonQuery();
            }                   
        }
        eventLog.WriteEntry(string.Format("{0} has been changed: {1}", e.Name, DateTime.Now), EventLogEntryType.Information);             
    }

问：在我看来，这种行为是不是我的代码，而是由操作系统设置引起的。 ？它可以是这样

Question: it seems to me that this behavior is caused not by my code but rather by operation system settings . Can it be so?

* *编辑：刚刚发现更具体的东西：

1）如果显示消息（当我想启动该服务）：

1) If it shows the message (when I want to start the service):

The [service name] service on local computer started and then stopped. ....

我需要改变来源 事件日志，重新编译和安装。而这一消息将不会出现; 。mabby下次

I need to change Source property of eventLog, rebuild and reinstall. And this message will not show up; mabby next time.

2）我有以下文件夹层次结构：图像/ PROD-图像。 图片和 PROD-图像目录中都包含的图像文件。当服务乳宁和我改变从 PROD-图像的图像文件夹消息被写入日志，因为我想和更新数据库。但有此事件发生后，服务将停止！ （我检查这3次）。当我重新启动，并再次重复这几次它更新的数据库，写日志，在3D时代，我得到

2) I have the following folders hierarchy: images/prod-images. images and prod-images directories both contain image files. When the service is runing and I change the image from prod-images folder the message is written into the log as I wanted and the database is updated. But after one this event the service stops! (I checked this 3 times). And when I restart it and repeat this again a couple of times it updates database, writes logs and on the 3d time I get

The [service name] service on local computer started and then stopped. ....

但是，这不是最好的部分）如果我改变是在图像图片目录我能做到这一点了多次，服务不停止。

But this is not the best part) If I change the image that is in images directory I can do it multiple times and the service doesn't stop. (only images from images/prod-images are bound to entries in the database).

所以（从图像/ PROD-图像绑定到数据库中的条目仅适用于图像），mabbe这功能莫名其妙referes来访问数据库

So, mabbe this feature somehow referes to the database accessing?

编辑2：在Visual Studio中我使用 DEBUG - >附加到进程调试服务。我设置的断点和改变形象。首次执行事件处理程序完美：在更新数据库并写入日志消息。但比我继续按F11（步入），并且该事件处理程序执行第二次。在行

Edits 2: in visual studio I use DEBUG -> Attach to Process to debug the service. I set up the breakpoints and change the image. First time the event handler executes flawlessly: the database is updated and the log message is written. But than I continue to press F11 (Step Into) and this event handler executes second time. At the line

var productId = Convert.ToInt32(Regex.Match(e.Name, @"\d+").Value); 

我得到 FormatException 是未处理。此后，我停止调试和维修站！就是这样：异常事件处理程序occures。

I get "FormatException was unhandled". After this I stop debugging and the service stops! That's it: the exception occures in event handler.

你有为什么执行第二次什么想法？谢谢！

Do You have any idea why it executes second time? Thanks!

PS 我已经submited DavutGürbüz答案，因为他指着我在正确的方向。结果
< STRONG>无论如何，检查出我自己的答案来解释实际问题。

P.S. I've already submited Davut Gürbüz answer cause he pointed me in the right direction.
Anyway, check out my own answer that explains the actual problem.

推荐答案

如果你有启停错误，这意味着你必须构造一个错误。

If you got start-stop error, this means you have an error in constructor.

将一个尝试捕捉到你的构造函数。您可以登录catch块到EventLog错误。

Put a try catch into your ctor. You may log the error to eventlog in catch block.

除了这个，我创建一个主要方法，并开始赢服务作为一个控制台应用程序。如果我的主要方法获取服务的实例我也可以调试。

Beside this I create a main method and start win service as a console app. If I get an instance of service in my main method I can also Debug it.

//You should select Console Application from Application properties
static void Main(string[] args)
    {
        MyWindowsService service = new MyWindowsService();

        if (Environment.UserInteractive)
        {
            service.OnStart(args);
            Console.WriteLine("Press any key to stop program");
            Console.Read();
            service.OnStop();
        }
        else
        {
            ServiceBase.Run(service);
        }

    } 

希望帮助

Hope helps

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