/// <summary> /// <para>Waits for the next event that matches the specified query to arrive, and /// then returns it.</para> /// </summary> /// <returns> /// <para>A <see cref='System.Management.ManagementBaseObject'/> representing the /// newly arrived event.</para> /// </returns> /// <remarks> /// <para>If the event watcher object contains options with /// a specified timeout, the API will wait for the next event only for the specified /// amount of time; otherwise, the API will be blocked until the next event occurs.</para> /// </remarks> public ManagementBaseObject WaitForNextEvent() { ManagementBaseObject obj = null; Initialize(); #pragma warning disable CA2002 lock (this) #pragma warning restore CA2002 { SecurityHandler securityHandler = Scope.GetSecurityHandler(); int status = (int)ManagementStatus.NoError; try { if (null == enumWbem) //don't have an enumerator yet - get it { //Execute the query status = scope.GetSecuredIWbemServicesHandler(Scope.GetIWbemServices()).ExecNotificationQuery_( query.QueryLanguage, query.QueryString, options.Flags, options.GetContext(), ref enumWbem); } if (status >= 0) { if ((cachedCount - cacheIndex) == 0) //cache is empty - need to get more objects { //Because Interop doesn't support custom marshalling for arrays, we have to use //the "DoNotMarshal" objects in the interop and then convert to the "FreeThreaded" //counterparts afterwards. IWbemClassObject_DoNotMarshal[] tempArray = new IWbemClassObject_DoNotMarshal[options.BlockSize]; int timeout = (ManagementOptions.InfiniteTimeout == options.Timeout) ? (int)tag_WBEM_TIMEOUT_TYPE.WBEM_INFINITE : (int)options.Timeout.TotalMilliseconds; status = scope.GetSecuredIEnumWbemClassObjectHandler(enumWbem).Next_(timeout, (uint)options.BlockSize, tempArray, ref cachedCount); cacheIndex = 0; if (status >= 0) { //Convert results and put them in cache. Note that we may have timed out //in which case we might not have all the objects. If no object can be returned //we throw a timeout exception. if (cachedCount == 0) { ManagementException.ThrowWithExtendedInfo(ManagementStatus.Timedout); } for (int i = 0; i < cachedCount; i++) { cachedObjects[i] = new IWbemClassObjectFreeThreaded(Marshal.GetIUnknownForObject(tempArray[i])); } } } if (status >= 0) { obj = new ManagementBaseObject(cachedObjects[cacheIndex]); cacheIndex++; } } } finally { securityHandler.Reset(); } if (status < 0) { if ((status & 0xfffff000) == 0x80041000) { ManagementException.ThrowWithExtendedInfo((ManagementStatus)status); } else { Marshal.ThrowExceptionForHR(status, WmiNetUtilsHelper.GetErrorInfo_f()); } } } return(obj); }