System.NullReferenceException 启动期间 Windows 服务出错

Question

在尝试启动我的 Windows 服务时，当状态栏快到 50% 时突然出现以下错误：

Error 1053: The service did not respond to the start or control request in timely fashion

当我检查事件查看器时，我看到以下错误：

Application: EnvMonService.exe

Framework Version: v4.0.30319

Description: The process was terminated due to an unhandled exception

Exception Info: System.NullReferenceException

Stack: at EnvMonService.EnvMonService..ctor() at EnvMonService.Program.Main()

我看不出错误的来源 - 这是我的代码：

主要()

static void Main()
{
    ServiceBase[] ServicesToRun;
    ServicesToRun = new ServiceBase[] 
    { 
         new EnvMonService() 
    };
    ServiceBase.Run(ServicesToRun);
}

构造函数

public EnvMonService()
{
    InitializeComponent();
}

OnStart 和 OnStop

protected override void OnStart(string[] args)
{
    // Start a task thread polling the databse for changes and updates the ASCII file
    mainTask = new Task(PollDatabase, cts.Token, TaskCreationOptions.LongRunning);
    mainTask.Start();
}


protected override void OnStop()
{
     // Cancel Task and wait for it to be disposed
     cts.Cancel();
     mainTask.Wait();
}

我的变量

// Connection to database
private string connString = ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString;

// Newest timestamp
private Int32 latestDate;

// Log file
public LogFileWriter logFileWriter;

// Define datastructure POCO class
EnvDataModel model = new EnvDataModel();

// Instantiate a concellation token for a task
private CancellationTokenSource cts = new CancellationTokenSource();

// Instantiate a task
private Task mainTask = null;

// Define a waiting interval between each database polling
private TimeSpan WaitAfterSuccessInterval = new TimeSpan(0, 1, 0);

// Define a waiting interval if any errors happens
private TimeSpan WaitAfterErrorInterval = new TimeSpan(0, 2, 0);

任务中的代码运行

    private void PollDatabase()
    {
     // New token
     CancellationToken cancellation = cts.Token;

     // Fencepost problem
     // Setup default interval
     TimeSpan interval = TimeSpan.Zero;

     // Create a new logfile instance
     logFileWriter = new LogFileWriter(@"C:\LogFile.txt");

     // Poll database until service stops
     while (!cancellation.WaitHandle.WaitOne(interval))
     {
          try
          {

              // Poll database here and assign reponse to EnvDataModel

              // Update status in logfile
              logFileWriter.WriteToLogFile("Database Last Polled: " + DateTime.Now + Environment.NewLine);

              // Call ASCII File Parser
              ParseDataToASCIIFileAsync();

              // Occasionally check the cancelation state
              if (cancellation.IsCancellationRequested)
              {
                  break;
              }
              interval = WaitAfterSuccessInterval;
           }
           catch (Exception caught)
           {
               // Log exception
               logFileWriter.WriteToLogFile(caught.Message);

               // Wait a few minutes before trying again
               interval = WaitAfterErrorInterval;
           }
      }
}

Answer 1

我通过以下步骤解决了我的问题：

在 Visual Studio 中，右键单击您的解决方案，然后单击 Clean Solution
再次右键单击您的解决方案，然后单击 Build Solution
[非强制] 将 bin/debug 文件夹中的所有文件复制到要从中运行服务的目录。该服务需要在您的本地驱动器上。
使用 Visual Studio 开发人员命令提示符和 installutil

System.NullReferenceException 启动期间 Windows 服务出错

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System.NullReferenceException 启动期间 Windows 服务出错

System.NullReferenceException error in Windows Service during start-up

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构造函数

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我的变量

任务中的代码 运行

任务中的代码运行