Trace.WriteLine(object value) - causes "System.InvalidOperationException: Collection was modified; e

[jc]

For some reason I am getting the following exception when calling
Trace.WriteLine(object value):

"System.InvalidOperationException: Collection was modified; enumeration
operation may not execute."

if (Trace.Listeners.Count > 0)
{
Trace.WriteLine(entry); // line 424
}

-

Here is the stack trace:

********* Exception details: **********
Unexpected exception. ---> System.InvalidOperationException: Collection
was modified; enumeration operation may not execute.
at System.Collections.ArrayList.ArrayListEnumeratorSimple.MoveNext()

at System.Diagnostics.TraceInternal.WriteLine(Object value)
at System.Diagnostics.Trace.WriteLine(Object value)
at MyLogger.Write(LogEntry entry) in MyLogger.cs:line 424

-

If I where to instead do the following, it would work.
So this seems that something in the framework is attempting to modify
the
Trace.Listeners collection:

for (int i = 0; i < Trace.Listeners.Count; i++)
{
TraceListener traceListener = Trace.Listeners;
traceListener.WriteLine(entry);
}

 

[RobinS]

Does the the object called "entry" have a ToString
method? Just for grins, try Trace.WriteLine(entry.ToString);
and see what that does.

Robin S.

 

[Laurent Bugnion]

Hi,

Does the the object called "entry" have a ToString
method? Just for grins, try Trace.WriteLine(entry.ToString);
and see what that does.

Robin S.

Every Object has a ToString() method, because it is defined in the
Object class. The only thing you can do is override it.
http://msdn2.microsoft.com/en-us/library/system.object.tostring(VS.80).aspx

HTH,
Laurent

 

[jc]

I found the issue:

In the TraceListener WriteLine implementation, we
had a try/catch block to intercept all exceptions and do the following.

try
{