/// <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);
}