未发现异常时启动ManagementEventWatcher

Question

未发现异常有时在启动MaagementEventWatcher

我的代码示例如下：

try 
     { 
      string scopePath = @"\\.\root\default"; 
      ManagementScope managementScope = new ManagementScope(scopePath); 
      WqlEventQuery query = 
       new WqlEventQuery(
        "SELECT * FROM RegistryKeyChangeEvent WHERE " + "Hive = 'HKEY_LOCAL_MACHINE'" 
        + @"AND KeyPath = 'HARDWARE\\DEVICEMAP\\SERIALCOMM'"); 
      registryWatcher = new ManagementEventWatcher(managementScope, query); 
      registryWatcher.EventArrived += new EventArrivedEventHandler(SerialCommRegistryUpdated); 

      registryWatcher.Start(); 
     } 
     catch (Exception ex) 
     { 
      Console.WriteLine(ex.Message); 
      if (registryWatcher != null) 
      { 
       registryWatcher.Stop(); 
      } 
     } 

例外：

Not found 
    at System.Management.ManagementException.ThrowWithExtendedInfo(ManagementStatus errorCode) 
    at System.Management.ManagementEventWatcher.Start() 
    at MTTS.LabX.RockLog.AppService.USBMonitor.AddRegistryWatcherHandler()] 

注：我查在注册表中找到文件夹和文件。

Answer 1

其实问题是，在笔记本电脑开始在注册表中没有创建第一次SERIALCOMM文件夹时，因为

基本上我们在USB端口或串行插入的设备（有这么COM1端口串行端口的PC）端口SERIALCOMM文件夹将创建，在这种情况下，我们正在使用WMI从注册表中获取连接的通信端口。

在一些笔记本电脑没有USB端口和串行端口连接所以，SERIALCOMM文件夹没有创建，在那段时间我们正在访问这个注册表路径，我们得到的错误。

所以解决的办法是，

try 
      { 
       string scopePath = @"\\.\root\default"; 
       ManagementScope managementScope = new ManagementScope(scopePath); 

       string subkey = "HARDWARE\\DEVICEMAP\\SERIALCOMM"; 

       using (RegistryKey prodx = Registry.LocalMachine) 
       { 
        prodx.CreateSubKey(subkey); 
       } 

       WqlEventQuery query = new WqlEventQuery(
        "SELECT * FROM RegistryKeyChangeEvent WHERE " + 
        "Hive = 'HKEY_LOCAL_MACHINE'" + 
        @"AND KeyPath = 'HARDWARE\\DEVICEMAP\\SERIALCOMM'"); 

       registryWatcher = new ManagementEventWatcher(managementScope, query); 

       registryWatcher.EventArrived += new EventArrivedEventHandler(SerialCommRegistryUpdated); 
       registryWatcher.Start(); 
      } 
      catch (Exception ex) 
      { 
       Console.WriteLine(ex.Message); 
       if (registryWatcher != null) 
       { 
        registryWatcher.Stop(); 
       } 
      } 

Answer 2

ManagementException在WQL查询中不匹配时会抛出ManagementException“未找到”。也许你指定了错误的KeyPath或KeyPath不再可用。