I would like Visual Studio to break when a handled exception happens (i.e. I don't just want to see a "First chance" message, I want to debug the actual exception).
e.g. I want the debugger to break at the exception:
try
{
System.IO.File.Delete(someFilename);
}
catch (Exception)
{
//we really don't care at runtime if the file couldn't be deleted
}
I came across these notes for Visual Studio.NET:
1) In VS.NET go to the Debug Menu >>
"Exceptions..." >> "Common Language
Runtime Exceptions" >> "System" and
select "System.NullReferenceException"
2) In the bottom of that dialog there
is a "When the exception is thrown:"
group box, select "Break into the
debugger"
3) Run your scenario. When the
exception is thrown, the debugger will
stop and notify you with a dialog that
says something like:
"An exception of type "System.NullReferenceException" has
been thrown.
[Break] [Continue]"
Hit [Break]. This will put you on the
line of code that's causing the
problem.
But they do not apply to Visual Studio 2005 (there is no Exceptions option on the Debug menu).
Does anyone know where the find this options dialog in Visual Studio that the "When the exception is thrown" group box, with the option to "Break into the debugger"?
Update: The problem was that my Debug menu didn't have an Exceptions item. I customized the menu to manually add it.
With a solution open, go to the Debug - Windows - Exception Settings (Ctrl+Alt+E) menu option. From there you can choose to break on Thrown or User-unhandled exceptions.
EDIT: My instance is set up with the C# "profile" perhaps it isn't there for other profiles?
There is an 'exceptions' window in VS2005 ... try Ctrl+Alt+E when debugging and click on the 'Thrown' checkbox for the exception you want to stop on.
Took me a while to find the new place for expection settings, therefore a new answer.
Since Visual Studio 2015 you control which Exceptions to stop on in the Exception Settings Window (Debug->Windows->Exception Settings). The shortcut is still Ctrl-Alt-E.
The simplest way to handle custom exceptions is selecting "all exceptions not in this list".
Here is a screenshot from the english version:
Here is a screenshot from the german version:
From Visual Studio 2015 and onward, you need to go to the "Exception Settings" dialog (Ctrl+Alt+E) and check off the "Common Language Runtime Exceptions" (or a specific one you want i.e. ArgumentNullException) to make it break on handled exceptions.
Step 1
Step 2
Check Managing Exceptions with the Debugger page, it explains how to set this up.
Essentially, here are the steps (during debugging):
On the Debug menu, click Exceptions.
In the Exceptions dialog box, select Thrown for an entire category of exceptions, for example, Common Language Runtime Exceptions.
-or-
Expand the node for a category of exceptions, for example, Common Language Runtime Exceptions, and select Thrown for a specific exception within that category.
A technique I use is something like the following. Define a global variable that you can use for one or multiple try catch blocks depending on what you're trying to debug and use the following structure:
if(!GlobalTestingBool)
{
try
{
SomeErrorProneMethod();
}
catch (...)
{
// ... Error handling ...
}
}
else
{
SomeErrorProneMethod();
}
I find this gives me a bit more flexibility in terms of testing because there are still some exceptions I don't want the IDE to break on.
The online documentation seems a little unclear, so I just performed a little test. Choosing to break on Thrown from the Exceptions dialog box causes the program execution to break on any exception, handled or unhandled. If you want to break on handled exceptions only, it seems your only recourse is to go through your code and put breakpoints on all your handled exceptions. This seems a little excessive, so it might be better to add a debug statement whenever you handle an exception. Then when you see that output, you can set a breakpoint at that line in the code.
There are some other aspects to this that need to be unpacked. Generally, an app should not throw exceptions unless something exceptional happens.
Microsoft's documentation says:
For conditions that are likely to occur but might trigger an exception, consider handling them in a way that will avoid the exception.
and
A class can provide methods or properties that enable you to avoid making a call that would trigger an exception.
Exceptions degrade performance and disrupt the debugging experience because you should be able to break on all exceptions in any running code.
If you find that your debugging experience is poor because the debugger constantly breaks on pointless exceptions, you may need to detect handled exceptions in your tests. This technique allows you to fail tests when code throws unexpected exceptions.
Here are some helper functions for doing that
public class HandledExceptionGuard
{
public static void DoesntThrowException(Action test,
Func<object?, Exception, bool>? ignoreException = null)
{
var errors = new List<ExceptionInformation>();
EventHandler<FirstChanceExceptionEventArgs> handler = (s, e) =>
{
if (e.Exception is AssertFailedException) return;
if (ignoreException?.Invoke(s, e.Exception) ?? false) return;
errors.Add(new ExceptionInformation(s, e.Exception, AppDomain.CurrentDomain.FriendlyName));
};
AppDomain.CurrentDomain.FirstChanceException += handler;
test();
AppDomain.CurrentDomain.FirstChanceException -= handler;
if (errors.Count > 0)
{
throw new ExceptionAssertionException(errors);
}
}
public async static Task DoesntThrowExceptionAsync(Func<Task> test,
Func<object?, Exception, bool>? ignoreException = null)
{
var errors = new List<ExceptionInformation>();
EventHandler<FirstChanceExceptionEventArgs> handler = (s, e) =>
{
if (e.Exception is AssertFailedException) return;
if (ignoreException?.Invoke(s, e.Exception) ?? false) return;
errors.Add(new ExceptionInformation(s, e.Exception, AppDomain.CurrentDomain.FriendlyName));
};
AppDomain.CurrentDomain.FirstChanceException += handler;
await test();
AppDomain.CurrentDomain.FirstChanceException -= handler;
if (errors.Count > 0)
{
throw new ExceptionAssertionException(errors);
}
}
}
If you wrap any code in these methods as below, the test will fail when a handled exception occurs. You can ignore exceptions with the callback. This validates your code against unwanted handled exceptions.
[TestClass]
public class HandledExceptionTests
{
private static void SyncMethod()
{
try
{
throw new Exception();
}
catch (Exception)
{
}
}
private static async Task AsyncMethod()
{
try
{
await Task.Run(() => throw new Exception());
}
catch (Exception)
{
}
}
[TestMethod]
public void SynchronousTest()
{
HandledExceptionGuard.DoesntThrowException(() => SyncMethod());
}
[TestMethod]
public async Task AsyncTest()
{
await HandledExceptionGuard.DoesntThrowExceptionAsync(() => AsyncMethod());
}
}
I have a stateful service that stores things in a IReliableDictionary. After deployed to local cluster, I restarted the primary node to test the failover, however, after I do that, the code StateManager.GetOrAddAsync>("MyDictionary") throws FabricNotPrimaryException, then in later trials it throws FabricObjectClosedException. What are some of the things that I can check to troubleshoot this?
The basic way to troubleshoot errors like this is to catch and log the exception being thrown:
try
{
using (var tx = StateManager.CreateTransaction())
{
await dictionary.AddOrUpdateAsync(tx, dto.Id, dto, (key, _) => dto);
await transaction.CommitAsync();
}
}
catch (FabricObjectClosedException ex)
{
ServiceEventSource.Current.Message(ex.ToString());
throw; // Pass the exception up as we only log it here.
}
However, your problem might be a very simple typo like a missing [DataContractAttribute] on a DTO class. In that case it might be easier to simply debug the problem to quickly understand and fix the problem. To do that you should add the System.Fabric.FabricObjectClosedException to Visual Studio and then enable "break when thrown" in the debugger:
Show the Exception Settings window (Debug > Windows > Exception Settings)
Select the Common Language Runtime Exceptions category in the list of exception categories
Click the green + (plus) button to add a new exception type
Type System.Fabric.FabricObjectClosedException in the text box and hit enter
When a new exception type is added the Break When Thrown check box is already checked.
Next time you execute your application in the debugger the debugger will break when a FabricObjectClosedException is thrown and you should be able to understand what went wrong.
Setup:
1) MSVS 2015, Option -> Debugger -> "Just My Code" is checked.
2) This sample code placed within some class and called during startup:
static bool TestIgnoreException()
{
Exception ex;
return TrySomething(out ex);
}
[DebuggerNonUserCode] // Prevent exceptions from stopping the debugger within this method.
static bool TrySomething(out Exception exOut)
{
try
{
if (Environment. MachineName.Length != -1)
throw new Exception("ThrewIt.");
exOut = null;
return true;
}
catch (Exception ex)
{
exOut = ex;
return false;
}
}
3) Launch Debugger
Expected result is that TestIgnoreException() runs silently and returns false.
Actual result is the debugger stops in TestIgnoreException() even though there should be no exception being processed at that scope.
4) Also re-tried using [DebuggerHidden] instead, same results.
Motivation:
The motivation is for cases where some API that is out of your control does not provide a "Try" method and instead only indicates failure by using exceptions.
One of numerous such examples is .NET TcpClient.Connect(host, port). Say a program always tests some connections during startup, the debugger should not stop on this particular section of code each time.
Using the standard "break when thrown" exceptions checkboxes is is not good because it works globally by type. It cannot be configured to work locally. Also other developers who check out the code should automatically skip the exception as well.
Mystery solved. It is indeed a known issue that is new to MSVS 2015 because of added exception handling optimizations.
https://blogs.msdn.microsoft.com/visualstudioalm/2016/02/12/using-the-debuggernonusercode-attribute-in-visual-studio-2015/#
There is a workaround posted on that link to disable the optimizations and enable the old behavior. Hopefully they will eventually be able to revive the support for this including the optimizations.
reg add HKCU\Software\Microsoft\VisualStudio\14.0_Config\Debugger\Engine /v AlwaysEnableExceptionCallbacksOutsideMyCode /t REG_DWORD /d 1
Related question:
Don't stop debugger at THAT exception when it's thrown and caught
When debugging my Winform program, I recently found that instead of breaking in the source code lines that do bad, the program will pop up a dialog showing error message, something like below:
This is not good for me as I didn't know where in the code that caused this failure, do you know why my Visual Studio debugger behaves like this and how can I alter this?
if you are running your application in Non-Debug mode it will not break your code ,it just displays the error message in MessageBox
if you want to throw exception and point to your code exactly where exception raised you need to Run you program in Debug mode.
EDIT: if you are already in Debug mode try this:
Step 1: Goto Debug menu in VS IDE
Step 2: Select Exceptions
Step 3: now You need to check the Common Language Runtime Exceptions option in Exceptions dialog.
I guess you catch exceptions in your program and show a message box in that case. Probably with a blanket catch (Exception e). You can make the debugger to break into any exception thrown, even if caught under Debug > Exceptions.
You could show the StackTrace instead of the Message, which contains a drill down to the call that caused the exception.
You could show your message like this:
try
{
// some code that throws an exception
}
catch()
{
StringBuilder sb = new StringBuilder();
sb.AppendFormat("Message: {0}", e.Message);
sb.AppendLine();
sb.AppendLine();
sb.AppendFormat("StackTrace: {0}", e.StackTrace);
MessageBox.Show(sb.ToString(), "Error");
}
I have unusual (for me) problem with thrown exception. After exception is thrown application loops on it and doesn't exit.
if(!foundRemoteID)
{
throw new ArgumentOutOfRangeException(
"value",
"Remote ID was not found."
);
}
I have inserted brakepoint on "if(!foundRemoteID)" line but the program doesn't hit it at all after firs thrown exception. It just loops over and over on "throw new (..).
-I do not have try{} catch{} blocks at all at any level.
-There is no loop that contains this code
I have even tried putting it into:
try
{
(..)
}
finally
{
Enviroment.Exit(1);
}
but finally{} block is never hit.
Other throw new (..) in this class is acting same way.
Am I missing something trivial?
UPDATE:
Problem is not related to my project. I have just created a simple console application that has only
throw new FileNotFoundException();
In Main() method and problem persists.
I have already tried resetting VS2010 settings to default and it didn't help.
Most likely this is not the actual behavior of your application - rather, Visual Studio is set to always break when there is an unhandled ArgumentOutOfRangeException.
You can verify this by pressing "Start without debugging".
If you want to change the settings, browse to the menu to Debug -> Exceptions and you should see the following. Then uncheck "User-unhandled."
Personally, I recommend leaving the setting the way it is in most cases. It really helps when hunting down unhandled exceptions.