I have some very simple code that is throwing a RuntimeBinderException
var mockString = "{ Status: \"Aware\" }";
dynamic d = JsonConvert.DeserializeObject(mockString);
OutputString = d.Status;
I have read a lot of the similar questions like this one and the answer given is that it is a first chance exception and I should check "Just My Code' in Tools > Options > Debugging.
I have the code in two solutions. One works and one does not. Both have the "Just My Code" option checked. Both are using the same version of Newtonsoft.Json (8.0.3)
This is VS 2015, Xamarin Forms running on Android.
In my case I had the debugger break on first chance exceptions for RuntimeBinderException, but when running on Android it was shown as "unhandled" exception in the debugger.
That threw me off for a moment, but after I found out I could continue running without problems I realised it was actually a first chance exception. After turning break on first chance exception of for RuntimeBinderException (since I wasn't interested in those at the time) it worked as expected.
To turn break on first chance exceptions on/off check the menu: Debug -> Windows -> Exception settings
Related
My main program is an ASP.Net Core Web API that has a third party library in a hosted service. The third party library is initializing fine but then it throws some errors sometime throughout its lifecycle.
It supplies a way of hooking into the object via an event and will let me know what the error is so that I can handle it but it still throws in the third party library..
Since I am handling the event myself, I want to completely ignore these errors that are occurring in this library. Is there anyway that I can do that?
I have already tried to add a global exception handler and the strange thing is, this exception handler never gets hit. The only way I can get the exception is to set my exception settings to break when CLR exceptions happen like in the picture above
This does not crash my program. For some reason, the program just hangs. When I turn off CLR exceptions in the "Break when thrown" window, then the program runs just fine. It is almost like visual studio is doing something special to handle these types of exceptions that a console version cannot do
The only way that I can seem to get a console version of this running, is attach a visual studio debugger to the process and when the exception is hit, press the green play button "Continue" in visual studio. Otherwise the application just seems to hang on the exception being thrown by the third party library.
The application will run fine as long as visual studio is attached and the CLR break exceptions are not checked
Does anyone know how to make sure that these types of exceptions do not hang the program when released?
Additional Info:
The third party library is a .NET Framework 4 library
The Asp.Net project is targetting "net5.0-windows"
The 3rd party class is probably using multi-threading
if it helps, this is how I am creating the third party class
Handling NullReferenceException in release code（Official advice）
It's usually better to avoid a NullReferenceException than to handle it after it occurs. Handling an exception can make your code harder to maintain and understand, and can sometimes introduce other bugs. A NullReferenceException is often a non-recoverable error. In these cases, letting the exception stop the app might be the best alternative.
However, there are many situations where handling the error can be useful:
1.Your app can ignore objects that are null. For example, if your app retrieves and processes records in a database, you might be able to ignore some number of bad records that result in null objects. Recording the bad data in a log file or in the application UI might be all you have to do.
2.You can recover from the exception. For example, a call to a web service that returns a reference type might return null if the connection is lost or the connection times out. You can attempt to reestablish the connection and try the call again.
3.You can restore the state of your app to a valid state. For example, you might be performing a multi-step task that requires you to save information to a data store before you call a method that throws a NullReferenceException. If the uninitialized object would corrupt the data record, you can remove the previous data before you close the app.
4.You want to report the exception. For example, if the error was caused by a mistake from the user of your app, you can generate a message to help them supply the correct information. You can also log information about the error to help you fix the problem. Some frameworks, like ASP.NET, have a high-level exception handler that captures all errors to that the app never crashes; in that case, logging the exception might be the only way you can know that it occurs.
So after days of research I've finally found an event to hook into to give you error messages from ANY source no matter how many level deep you go in threads.
AppDomain.CurrentDomain.FirstChanceException += CurrentDomain_FirstChanceException;
Hooking into this event it will allow you to see errors from every library and every thread. Simply place the above into you program.cs (or whatever startup file you have) and magically you will be flooded with all of the unknown errors from all of the 3rd party libraries you thought were once flawless.
private static void CurrentDomain_FirstChanceException(object sender, System.Runtime.ExceptionServices.FirstChanceExceptionEventArgs e)
{
Console.WriteLine(e.Exception.Message, e.Exception.StackTrace);
}
I've done so with the following method and low and behold. The third party library was trying to reference another project in an unsafe way and throwing an error. Since I didn't need this other project reference the built exe did not have a reference to this assembly because I had no direct reference to it in the project (darn smarty pants who need to optimize everything). I was able to run correctly because in my visual studio solution, I had a reference to this other project. So the third party library would pick up on it as soon as visual studio connected with the debugger through some sort of dark magic.
Anyways, I made a throw away object that used the project that was required and the issue was solved.
I really hope that this helps someone else and saves them the days it took me to find this.
I have a function in vb.net that is shared. At one point it throws an error that says an 'open datareader already exists'. But this function is called from several different places in the program. How can I find out which part of the program called the function when it errors out?
You go to the Debug menu, show the Exceptions window, put a tick next to CLR exceptions and then run your program until it errors. As soon as the exception is raised VS will break, you will be able to see the call stack, and find out where the code was before. Note that this causes VS to stop on every exception, handled or not; it can become tedious to get to where you want to be - untick the "always break when this type of exception is thrown" in the exception helper if you just keep getting irrelevant exceptions breaking before this error you're trying to chase
It sounds like you're perhaps not creating/disposing of your DB access resources properly, especially if this is a static/shared context. Are you trying to reuse one DB connection? It wouldn't hurt to post the code of the faulting module
All of a sudden the errors that Dojo (1.8.3 from Google CDN) is spitting out empty errors, which makes debugging impossibly hard. For example, if I forget to require a dependent before using it, I get the usual
> dojo/parser::parse() error ReferenceError {}
... in the error console, but I remember getting more information in the ReferenceError (spindown arrow was present), giving me the arguments of the error as well as the message making it easy to figure out what I had done wrong.
I have isDebug : true in my dojoConfig, but it just doesn't want to tell me anything anymore.
What gives?
I've been having the same problem using Dojo 1.8.3 as well. When I close my developer tool's console and then re-open it the Error had the spindown and more details as expected. Seems stupid, but give it a try and see if that at "fixes" it for you. I planned on digging a little further into this later, so if I find any additional details I will make sure to update my answer with them.
I have migrated my ASP.NET MVC 2 project to VS 2010 + .NET 4.0.
Now when i start the application i get a lot of "CultureNotFoundException" in IntelliTrace and Output/Gebug window :
A first chance exception of type 'System.Globalization.CultureNotFoundException' occurred in mscorlib.dll
I know what "A first chance exception" means, but when i try to debug(added "CultureNotFoundException" into Bebug/Exceptions[Thrown]) why ex. is thrown i got this detailed exception text:
System.Globalization.CultureNotFoundException occurred
Message=Culture is not supported.
Parameter name: name
designer is an invalid culture identifier.
Source=mscorlib
ParamName=name
InvalidCultureName=designer
StackTrace:
at System.Globalization.CultureInfo..ctor(String name, Boolean useUserOverride)
InnerException:
I wonder why .NET is trying to create CultureInfo with name "designer"?
Isn't it bug?
I had a similar issue with the CultureName "UserCache". To resolve this I deleted all the folders from in here:
C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files
For other people that have this problem, this is usually an exception that is ignored.
Go to the Debug menu -> Exceptions... and ensure that you have everything unchecked for the Exception list.
This is actually by design in System.Web (at least up until .NET Framework v4.0), not necessarily the best approach, but it works.
You can find a more detailed description here, but it basically happens because ASP.NET checks every single folder to see if it contains satellite assemblies, and throws an exception otherwise.
Given that satellite assemblies live in folders with predictable names, one would wonder why they would decide to do this rather than only check folders that match the pattern, particularly since handling exceptions is rather expensive computationally compared to a simple conditional check.
I was curious as to the cause to see if there was something I could personally do to eliminate this particular annoyance.
The Exception is a side effect of calling, "System.Web.UI.Util.IsCultureName(name)"
The first time it's called in my MVC3 application is in regards to a directory called "UserCache", which is in the same directory as several directories with the expected culture names "en-US", etc. .Net is trying to find Satellite directories for the application.
It's called multiple times, even relating to files that are culture files, "EditorLocalization.bg-BG.designer.cs" for example (actually all of these that are in App_GlobalResources). [ What the code does here is to take all the files in App_GlobalResources, and see if the file ends in a CultureName, again calling IsCultureName.
So there's nothing you can really do to avoid this... In production where the .cs classes won't be there, perhaps it won't happen. It certainly slows down startup quite a bit, though!
In any case, in my mind it's a total bug that Microsoft throws an exception inside, "IsCultureName().
Go to the Debug -> Options in Visual Studio and check "Just My Code".
I found that turning on "Enable Just My Code" in the Debugging section of the Visual Studio 2017 options worked for me. That just hides those exceptions, which are part of the normal operation of the framework.
I had a similar issue with the "CultureNotFoundException". To resolve this I had to delete all the folders from in here additionally:
%LocalAppData%\Local\Temp\Temporary ASP.NET Files
Deleting from here wasn't enough:
C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files
I had this error message:
'ViewBag.XXXXX' threw an exception of type 'System.Globalization.CultureNotFoundException' dynamic {System.Globalization.CultureNotFoundException}
The inner message said:
The culture is not supported.\r\nParameter name: name\r\nneutral is an invalid identifier culture.
The problem was that there was an invalid definition of the assembly culture in the AssemblyInfo.cs file:
[assembly: AssemblyCulture("neutral")]
To fix it, just leave empty the "culture" parameter like this:
[assembly: AssemblyCulture("")]
That fixed the problem for me.
I think it's the actual designer that messed things up. Try searching across your solution for "designer" string to see if any XML/HTML attributes have their values set to this string.
It seems as the problem was a bug in VS 2010 Beta 2.
've been running through the MSDN help documents to get a hang of Visual Basic. After trying out the example using timers --one drags a label and timer component into the designer and adds the following to the components subroutine
Label1.Text = My.Computer.Clock.LocalTime.ToLongTimeString
The output for the immediate window during debug is the following
A first chance exception of type
'System.InvalidCastException' occured
in Microsoft.VisualBasic.dll
A first
chance exception of type
'System.InvalidCastException' occured
in Microsoft.VisualBasic.dll
The same error occurs on a previous MSDN example using a context menu component. Should I Try...Catch...Finally this error and try to move on? Or, am I dealing with something much more serious?
When you see something about a first chance exception, it only means that an exception was caught within the code you called but does not necessarily mean that the code failed. If the code runs without causing your program to crash and returns a valid value, then do not have a problem. You will also see output in the debug window about first chance exceptions when you implement your own try/catch blocks.
In the Debug menu -> Exceptions, you can enable the debugger to stop when an Exception is first thrown, even if it would be caught later; if you want to find out what's happening, this is the easiest way to do it
In the first chance exception examine the details of the exception. You should see a stack frame/trace property. In there you should see what line the error occurs on. This should help you.
In the IDE try going to Tools > Options > Projects and Solutions > VB Defaults and setting Option Strict to 'On' - this may help catch casting problems when you compile your project rather than when you run it.
A 'first chance execption' does not necessarily mean you have a problem in your code. It could mean the IDE or the compiler or any other involved component encountered and handled an error and in the process the debugger is notified and the exception is being reported to the immediate window. This is an excellent post on the topic:
http://blogs.msdn.com/davidklinems/archive/2005/07/12/438061.aspx
A quick and easy solution for debug and diag of First Chance Exception is :
AppDomain.CurrentDomain.FirstChanceException += CurrentDomainOnFirstChanceException;
and then
private void CurrentDomainOnFirstChanceException(object sender, FirstChanceExceptionEventArgs firstChanceExceptionEventArgs)
{
if (firstChanceExceptionEventArgs.Exception is NullReferenceException)
{
// do your handling and debugging :)
}
}
Multiple First Chance Exception during the runtime can cripple the performance of your application because exception handling is expensive. Especially in web apps. You can add this handler and look at specific first chance exceptions and try to avoid/correct them.