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C# Try/Catch doesn't catch exception

I got an issue with a try catch block. It doesn't catch the exception of the code in the try block. Does anybody already had an issue like that and know how to solve it. The variable myCon is a MySqlConnection. The Exception occurs when the wait_timeout of the session is exceeded. Restarting, Rebuilt, change of CPU settings already tried.
P.S. When I press F10/F5 it doesn't jump into the catch block

I am not sure, but I can't see that Ping() is actually letting exceptions pass through. It just returns true or false.
For example the Open() method actually might throw an exception of type MySqlException, but not Ping()

It probably is the debug point made by Jon Skeet and Steven Wood, if not, have you tried removing HandleProcessCorruptedStateExceptions?

Try/Catch not catching System.Threading.ThreadAbortException in ReportDocument.ExportToHttpResponse

I am trying to export a Crystal ReportDocument using ExportToHttpResponse like so:
report.ExportToHttpResponse(exportOptions, HttpContext.Current.Response, true, "test");
When I first tried to run this, I received a System.Threading.ThreadAbortException. After reading about how this is a known error with ExportToHttpResponse in this question, I tried implementing the suggested workaround of wrapping the statement in a try/catch block like so:
try
{
report.ExportToHttpResponse(expOptions, HttpContext.Current.Response, true, "test");
}
catch (System.Threading.ThreadAbortException e)
{
}
As I understand it, this should catch and ignore the error, and proceed. However, I am still getting the System.Threading.ThreadAbortException on the closing bracket of the catch statement. My question is why is the exception still being received even though I am apparently catching it, and how could I go about fixing it so that the exception is ignored?

You can catch the ThreadAbortException and call the Thread.REsetAbort method, to cancel the bubbling of the exception.
However, keep in mind that response.end is a bad idea. Whenever you can try to call HttpApplication.CompleteRequest(), and read this SO question which proved really useful to me in this regard.

Catching an Exception across treeview.Nodes.Add / treeview_AfterSelect event boundary

There is a place in my WinForms program that throws a MyOwnException.
void CodeThatThrowsMyOwnException()
{
...
throw new MyOwnException("Deep Inside");
...
}
Further up the stack, there is a simple try/catch block
try
{
CodeThatThrowsMyOwnException();
}
catch (MyOwnException moe)
{
MessageBox.Show("Hit this point in the code! Hurray!");
}
MessageBox.Show("Later, alligator.");
On a colleague's computer (running VS 2008 SP1 like me) the dialog box shows up. On my computer, it never catches the exception nor shows the dialog box. When I place a breakpoint deep inside the code (CodeThatThrowsMyOwnException) on the line that throws the Exception, it hits the breakpoint on the line. If I press F5 (Debug > Run) it skips passed my catch block and displays the "Later, alligator" message.
Actually pasting the "void CodeThatThrowsMyOwnException() { throw new MyOwnException("Shallow"); }" code into my code (instead of calling my real code) and literally calling "CodeThatThrowsMyOwnException();" in the try block does however get show the message in the catch block.
As far as I can tell, I am not creating any threads and I have looked for try {} catch {} blocks that catch all exceptions but cannot find any in the involved projects (and if they were in there, why would this catch block still work on my colleague's machine?)
Strangely enough running my code by double clicking the executable gives me an unhandled exception on my machine and the same on my colleague's machine. This is a clue that led me to try the following:
When I place a breakpoint at the throw MyOwnException("Deep Inside") line deep inside my code, the call stack contains a line "[External Code]" between my exception handler and the place where I call 'throw MyOwnException("Deep Inside")'. If I put a try/catch MyOwnException block further away from the throw (but on this side of the [External Code] I can still catch the exception, anywhere I place the try catch block (around relevant parts of the function chain):
try
{
CodeChain(...);
}
catch (DrawException de)
{
MessageBox.Show("Hurray!"); // being executed, but only on the 'throw' side of the [External Code] part of the call stack
}
However, when I step outside (below on the stack) the [External Code], the exception does not fire. This is unexpected:
try
{
treeview.Nodes.Add(treeNode); // triggers the aforementioned chain of code with MyOwnException thrown
}
catch (DrawException de) // no matter what I do, this will not handle my cursed MyOwnException
{
MessageBox.Show("Hurray!"); // not being executed
}
This is the heart of my problem: I can't move my catch up the call stack because I need to run lots of tests (see below).
I have a sort of hypothesis, which is that his debugger is magically lifting the exception across thread boundaries (or across external code, i.e. Windows GUI events) in his debugger, whereas in the other three situations (my debugger (without the 64 bit extensions) and also when either machine runs the EXE from windows explorer the exception) the exception is truly unhandled on that thread.
So how do I catch this exception? Re-engineer my whole system to avoid using treeview.AfterSelect? Clearly I don't understand the limitations of exceptions.
Potential problem?
I have a delegate in there to keep my system modular and reusable. Can exceptions be thrown "through" a delegate, across module boundaries?
What I'm trying to accomplish (Testing Harness) and why I need Exceptions
I'm using this in an automated test harness. I need to fix some really tough logical/algorithmic bugs in a complicated GUI system by replaying action scripts (text files) that find these exceptional circumstances and narrow the problem down. (There is probably no good workaround to this in my program, in terms of rewriting or refactoring the design: I need to catch these Exceptions in this QA phase, fix the bugs (tough algorithmic special cases) before I ship so I don't subject my users to such buggy software. It's not like I'm using exceptions for exotic control flow for for fun (cf. Int32.Parse).)

The treeview_AfterSelect is going to be called most of the time by what you're referring to as [External Code]. These will be the result of the user selecting a node or even when the form is loading and you're adding nodes (which I suspect might be happening on your unhandled exception).
If your AfterSelect handler is going to throw exceptions for some reason, you cannot rely on your calling code to handle those exceptions. Otherwise, any other way that AfterSelect gets called could result in an unhandled exception.

how to handle this ThreadAbort Exception..?

i got this exception when i done the code given below..
"Unable to evaluate expression because the code is optimized or a native frame is on top of the call stack."
--code--
try
{
if (retVal == 0)
Response.Redirect("Success.aspx");
}
catch(Exception error)
{
Response.Redirect("errorpage.aspx");
}
finally{
}
from searching in net i found it to be a bug and if its success then we should end response... ie " Response.Redirect("Success.aspx", false); ".it works fine.. is this a good method or there is any other efficient method to handle this exception please help....

Are you sure that it's an Exception? What type of exception is it?
It looks more like you have used 'Break' in the debugger and it cannot evaluate a watch or expression because it's busy running a line of code or non-managed call.
Try pressing F10 or F11 to step to the next line of managed code then looking at the expression again.
Using a breakpoint should also work.
If that doesn't solve it, please post a comment and I will try to respond or be more specific.
This is probably what you are seeing:
Also, Response.Redirect will always throw a ThreadAbortException, see here:
http://msdn.microsoft.com/en-us/library/a8wa7sdt(VS.80).aspx
To ensure that no more code gets executed, and the next code that will be run is in the context of generating the next page.
You could do this instead:
try
{
// code with Response.Redirect
}
catch (ThreadAbortException)
{
// ignore this exception, it is expected from Response.Redirect
}
catch (Exception ex)
{
// handle / log / redirect using ex
}
Hope that helps!

Unhandled exception in try-catch

try
{
list = from XElement e in d.Descendants(wix + "File")
where e.Attribute("Name").Value.Contains(temp.Name) &&
e.Parent.Parent.Attribute("Name").Value.Contains(temp.Directory.Name)
select e;
}
catch (NullReferenceException e)
{
MessageBox.Show(e.Message);
}
catch (Exception e)
{
MessageBox.Show(e.Message);
}
now my question is why does this code produce a run time error saying I have a NullReferenceException unhandled. If you need more information about the program let me know.
EDIT:
The debugger points to the "where" part of the linq statement. When I run this program direct from the exe file I still get the exception.

EDIT: Okay, I think I know the problem... it's due to deferred query execution.
If you've just got the query construction in the try/catch block, that's not going to catch exceptions which occur while the query is being executed.
Look at the stack trace you've got, and you'll find that there'll be a stack frame where you're executing the query - it's just the auto-generated lambda expression which comes from this bit of code, and it's not running within the scope of the try/catch block.
ORIGINAL ANSWER:
Are you just seeing the exception in the debugger? If so, go into the debugger exception dialog and change the preferences for the point at which exceptions cause the debugger to "break". The catch block should be handling the NullReferenceException normally. (Admittedly I don't think you should really be catching NullReferenceException in the first place, and catching all exceptions like that is generally a bad idea too, other than at the top of the stack - but that's a different matter.)