系统.Windows Service启动时出现NullReferenceException错误

在尝试启动Windows服务时，当状态栏几乎处于50%时突然出现以下错误:

错误1053:服务没有及时响应启动或控制请求

当我检查事件查看器时，我看到以下错误:

应用程序:EnvMonService.exe

框架版本:v4.0.30319

描述:进程因未处理的异常而终止

Exception Info: System。得到NullReferenceException

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

我看不到错误来自哪里-这是我的代码:

Main ()

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);

在任务

中运行的代码

    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;
           }
      }
}