未發現異常時啓動ManagementEventWatcher

Question

未發現異常有時在啓動MaagementEventWatcher

我的代碼示例如下：

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：我查在註冊表中找到文件夾和文件。

Answer 1

其實問題是，在筆記本電腦開始在註冊表中沒有創建第一次SERIALCOMM文件夾時，因爲

基本上我們在USB端口或串行插入的設備（有這麼COM1端口串行端口的PC）端口SERIALCOMM文件夾將創建，在這種情況下，我們正在使用WMI從註冊表中獲取連接的通信端口。

在一些筆記本電腦沒有USB端口和串行端口連接所以，SERIALCOMM文件夾沒有創建，在那段時間我們正在訪問這個註冊表路徑，我們得到的錯誤。

所以解決的辦法是，

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查詢中不匹配時會拋出ManagementException「未找到」。也許你指定了錯誤的KeyPath或KeyPath不再可用。