问题
i can succesfully read events from event log. But polling all events has very bad performance. I wonder if there is an event or something that i can subscribe to catch log entries "as they happen"?
Is this possible?
EventLog log = new EventLog("Security");
var entries = log.Entries.Cast<EventLogEntry>().Where(x => x.InstanceId == 4624).Select(x => new
{
x.MachineName,
x.Site,
x.Source,
x.UserName,
x.Message
}).ToList();
Console.WriteLine(entries[0].UserName);
回答1:
You can use EventLogWatcher for this purpose. You can subscribe to desired log filter(s) and implement a handler function to execute when you receive any events.
public static void eventLogSubscription()
{
using (EventLog eventLog = new EventLog("Application"))
{
String path = Path.GetTempPath();
eventLog.Source = "Event Log Reader Application";
eventLog.WriteEvent(new EventInstance(1003, 0, EventLogEntryType.Information), new object[] { "The event log watcher has started" , path});
//eventLog.WriteEntry(arg.EventRecord.ToXml(), EventLogEntryType.Information, 1001, 1);
eventLog.Dispose();
}
EventLogWatcher watcher = null;
try
{
string eventQueryString = "*[System/EventID=4688]" +
"and " +
"*[EventData[Data[@Name = 'NewProcessName'] = 'C:\\Windows\\explorer.exe']] )" +
EventLogQuery eventQuery = new EventLogQuery(
"Security", PathType.LogName, eventQueryString);
watcher = new EventLogWatcher(eventQuery);
watcher.EventRecordWritten +=
new EventHandler<EventRecordWrittenEventArgs>(
handlerExplorerLaunch);
watcher.Enabled = true;
}
}
catch (EventLogReadingException e)
{
Console.WriteLine("Error reading the log: {0}", e.Message);
}
Console.ReadKey();
}
public static void handlerExplorerLaunch(object obj,
EventRecordWrittenEventArgs arg)
{ if (arg.EventRecord != null)
{
using (EventLog eventLog = new EventLog("Application"))
{
eventLog.Source = "Event Log Reader Application";
eventLog.WriteEvent(new EventInstance(1001, 0, EventLogEntryType.Information), new object[] {arg.EventRecord.FormatDescription() });
//eventLog.WriteEntry(arg.EventRecord.ToXml(), EventLogEntryType.Information, 1001, 1);
eventLog.Dispose();
}
}
else
{
Console.WriteLine("The event instance was null.");
}
}
来源:https://stackoverflow.com/questions/42168823/c-sharp-read-real-time-from-windows-event-log