Writing to EventLog Error (not ASP.Net)

Writing to EventLog Error (not ASP.Net)

Post by Mike » Fri, 20 Jun 2008 23:09:50

I created a simple console app that registers and event source and
write a test entry. The event source is registered properly but when
I go to write the entry I get the "Cannot open log file for source
'{0}'" error. (this occurs in Windows XP_

An inner exception says "The handle is invalid"

I have traced this down to EventLog.OpenForWrite(machineName) on this
line of code:

writeHandle =
if (writeHandle.IsInvalid) {
Win32Exception e = null;
if (Marshal.GetLastWin32Error() != 0) {
e = SharedUtils.CreateSafeWin32Exception();
throw new
sourceName), e);

The user context is an administrator on the machine. The error
suggests a security issue but it appears to be something else.

I've tested the same code in Windows Vista, and it fails before this
line of code. That error message points to a security problem,
probably UAC.

Here is a snippet of my code that produces this error:

EventSourceCreationData eData = new
EventSourceCreationData(sourceName, logName);
eData.MachineName = (machineName ?? ".");


EventLog el = new EventLog(eData.LogName,
eData.MachineName, eData.Source);
el.Wri *** try(testEvent, EventLogEntryType.Information);

I'm stuck! Can anyone help?


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2. ASP not writing to Eventlog

I have a VB, ASP program running on IIS 6.0.
The VB ActiveX dll writes events to eventlog using the following line
of code:

App.LogEvent (Err.Number & " " & Err.Description & " Source: " &

The above dll is complied and is called in ASP page as follows:

if err.number <> 0 then

set myObj = server.CreateObject("ErrorHandler.Class1")
myobj.WinNTLog err.number, err.description, err.source, errmsg, 1
set myobj = nothing

End if

The above code works fine when I run IIS under integrated account. I
pass my administrative crednetials on the server.

But when I run the above under anonymous account, then nothing gets
logged on to the eventlog. Any idea what is going on?


I tried to implement your code in my project at

It works totally fine when I run IIS6.0 in integrated environment. But
when I use anonymous account, then nothing gets logged in eventlog.

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