/// <summary>
/// Creates a new WMIInstanceWatcher with the specified poll interval.
/// </summary>
/// <param name="pollInterval">Polling interval between checks for new events</param>
public WMIInstanceWatcher(TimeSpan pollInterval)
{
var wmiClassName = WMIUtils.GetWMIClassName <T>();
var condition = string.Format("(TargetInstance ISA '{0}')", wmiClassName);
var createEventQuery = new WqlEventQuery
{
EventClassName = "__InstanceCreationEvent",
WithinInterval = pollInterval,
Condition = condition
};
var deleteEventQuery = new WqlEventQuery
{
EventClassName = "__InstanceDeletionEvent",
WithinInterval = pollInterval,
Condition = condition
};
var createWatcher = new ManagementEventWatcher();
createWatcher.EventArrived += HandleCreateEvent;
createWatcher.Query = createEventQuery;
var deleteWatcher = new ManagementEventWatcher();
deleteWatcher.EventArrived += HandleDeleteEvent;
deleteWatcher.Query = deleteEventQuery;
Watchers.Add(createWatcher);
Watchers.Add(deleteWatcher);
}
private void HandleEvent(object sender, EventArrivedEventArgs args)
{
if (EventOccurred == null)
{
return;
}
T instance = WMIUtils.FromEvent <T>(args);
EventOccurred(instance);
}
private void HandleDeleteEvent(object sender, EventArrivedEventArgs args)
{
if (InstanceDeleted == null)
{
return;
}
var obj = args.NewEvent.GetPropertyValue("TargetInstance");
T instance = WMIUtils.FromManagementObject <T>(obj as ManagementBaseObject);
InstanceCreated(instance);
}
/// <summary>
/// Constructs a new WMIWatcher that watches for WMI events related to the WMI class specified by the type parameter.
/// </summary>
public WMIEventWatcher()
{
var wmiClassName = WMIUtils.GetWMIClassName <T>();
var query = string.Format("SELECT * FROM {0}", wmiClassName);
var watcher = new ManagementEventWatcher();
watcher.EventArrived += HandleEvent;
watcher.Query = new WqlEventQuery(query);
Watchers.Add(watcher);
}