尝试卸载服务时未将对象引用设置为对象的实例c#答案

【问题标题】：Object reference not set to an instance of an object when trying to unninstall a service c#尝试卸载服务时未将对象引用设置为对象的实例c#
【发布时间】：2016-08-01 22:34:54
【问题描述】：

我有以下代码可以停止和卸载服务。它正确停止了服务，但是当我尝试卸载时它给了我这个错误：

System.NullReferenceException: Object reference not set to an instance of an object.
   at System.Configuration.Install.Installer.Uninstall(IDictionary savedState)
   at System.ServiceProcess.ServiceInstaller.Uninstall(IDictionary savedState)
   at UpdateOrca.FuncoesUpdater.StopService(String serviceName, Int32 timeoutMilliseconds, Boolean Unninstall) in C:\Users\me\Downloads\UpdateOrcaV2013\UpdateOrca\UpdateOrca\FuncoesUpdater.cs:line 165

代码：

    public void StopService(string serviceName, int timeoutMilliseconds, bool Unninstall)
    {
        if (ServicoInstalado(serviceName) == true) //&& ServiceRunning(serviceName) == true
        {
            ServiceController service = new ServiceController(serviceName);
            try
            {
                TimeSpan timeout = TimeSpan.FromMilliseconds(timeoutMilliseconds);

                service.Stop();
                service.WaitForStatus(ServiceControllerStatus.Stopped, timeout);
                ServiceInstaller ServiceInstallerObj = new ServiceInstaller();
                if (Unninstall == true)
                {
                    ServiceInstallerObj.ServiceName = serviceName;
                    ServiceInstallerObj.Uninstall(null); (LINE OF THE ERROR)
                }

            }
            catch (Exception ex)
            {
                Program.Erro = ex.ToString();
                Erro NewErro = new Erro();
                NewErro.ShowDialog();
            }
        }
    }

【问题讨论】：

标签： c# object reference

【解决方案1】：

ServiceInstaller.Uninstall() 方法实际上需要有关您要卸载的内容的某种类型的上下文信息。这通常可以作为IDictionary 对象传递给Uninstall() 方法，但如果您决定传递null，则可能需要显式设置上下文：

// Build your uninstaller
ServiceInstaller ServiceInstallerObj = new ServiceInstaller();
if (Unninstall)
{
      // Set a context (using a specific file to log uninstall info)
      ServiceInstallerObj.Context = new InstallContext("{path-to-log-file}", null);
      // Continue setting your service and uninstalling it
      ServiceInstallerObj.ServiceName = serviceName;
      ServiceInstallerObj.Uninstall(null); 
}

如果这不起作用，您可以考虑尝试类似于this related discussion 中提到的方法。

【讨论】：