How to handle AccessViolationException

Question

I am using a COM object  MODI  from within my  net application   The method I am calling throws a System AccessViolationException  which is intercepted by Visual Studio   The odd thing is that I have wrapped my call in a try catch  which has handlers for AccessViolationException  COMException and everything else  but when Visual Studio  2010  intercepts the AccessViolationException  the debugger breaks on the method call  doc OCR   and if I step through  it continues to the next line instead of entering the catch block  Additionally   if I run this outside of the visual studio my application crashes  How can I handle this exception that is thrown within the COM object  MODI Document doc   new MODI Document    try       doc Create sFileName       try               doc OCR MODI MiLANGUAGES miLANG ENGLISH  false  false           sText   doc Images 0  Layout Text            catch  System AccessViolationException ex                  MODI seems to get access violations for some reason  but is still able to return the OCR text          sText   doc Images 0  Layout Text            catch  System Runtime InteropServices COMException ex                  if no text exists  the engine throws an exception          sText    quot  quot             catch               sText    quot  quot              if  sText    null                sText   sText Trim            finally       doc Close false          Cleanup routine  this is how we are able to delete files used by MODI      System Runtime InteropServices Marshal FinalReleaseComObject doc       doc   null      GC WaitForPendingFinalizers        GC Collect        GC WaitForPendingFinalizers

User · Accepted Answer

In  NET 4 0  the runtime handles certain exceptions raised as Windows Structured Error Handling  SEH  errors as indicators of Corrupted State   These Corrupted State Exceptions  CSE  are not allowed to be caught by your standard managed code   I won t get into the why s or how s here   Read this article about CSE s in the  NET 4 0 Framework   http   msdn microsoft com en-us magazine dd419661 aspx id0070035  But there is hope   There are a few ways to get around this    Recompile as a  NET 3 5 assembly and run it in  NET 4 0  Add a line to your application s config file under the configuration runtime element   lt legacyCorruptedStateExceptionsPolicy enabled  true false   gt  Decorate the methods you want to catch these exceptions in with the HandleProcessCorruptedStateExceptions attribute   See http   msdn microsoft com en-us magazine dd419661 aspx id0070035 for details      EDIT  Previously  I referenced a forum post for additional details   But since Microsoft Connect has been retired  here are the additional details in case you re interested   From Gaurav Khanna  a developer from the Microsoft CLR Team     This behaviour is by design due to a feature of CLR 4 0 called Corrupted State Exceptions  Simply put  managed code shouldnt make an attempt to catch exceptions that indicate corrupted process state and AV is one of them    He then goes on to reference the documentation on the HandleProcessCorruptedStateExceptionsAttribute and the above article   Suffice to say  it s definitely worth a read if you re considering catching these types of exceptions

User · Answer

Microsoft   quot Corrupted process state exceptions are exceptions that indicate that the state of a process has been corrupted  We do not recommend executing your application in this state     If you are absolutely sure that you want to maintain your handling of these exceptions  you must apply the HandleProcessCorruptedStateExceptionsAttribute attribute quot  Microsoft   quot Use application domains to isolate tasks that might bring down a process  quot  The program below will protect your main application thread from unrecoverable failures without risks associated with use of HandleProcessCorruptedStateExceptions and  lt legacyCorruptedStateExceptionsPolicy gt  public class BoundaryLessExecHelper   MarshalByRefObject       public void DoSomething MethodParams parms  Action action                if  action    null              action            parms BeenThere   true     example of return value          public struct MethodParams       public bool BeenThere   get  set       class Program       static void InvokeCse                 IntPtr ptr   new IntPtr 123           System Runtime InteropServices Marshal StructureToPtr 123  ptr  true              private static void ExecInThisDomain                 try                       var o   new BoundaryLessExecHelper                var p   new MethodParams     BeenThere   false                Console WriteLine  quot Before call quot                 o DoSomething p  CausesAccessViolation               Console WriteLine  quot After call  param been there     quot    p BeenThere ToString       never stops here                   catch  Exception exc                        Console WriteLine   quot CSE   exc ToString    quot                      Console ReadLine                private static void ExecInAnotherDomain                 AppDomain dom   null           try                       dom   AppDomain CreateDomain  quot newDomain quot                var p   new MethodParams     BeenThere   false                var o    BoundaryLessExecHelper dom CreateInstanceAndUnwrap typeof BoundaryLessExecHelper  Assembly FullName  typeof BoundaryLessExecHelper  FullName                        Console WriteLine  quot Before call quot                 o DoSomething p  CausesAccessViolation               Console WriteLine  quot After call  param been there     quot    p BeenThere ToString        never gets to here                   catch  Exception exc                        Console WriteLine   quot CSE   exc ToString    quot                      finally                       AppDomain Unload dom                      Console ReadLine                static void Main string   args                ExecInAnotherDomain       this will not break app         ExecInThisDomain        this will

User · Answer

Compiled from above answers  worked for me  did following steps to catch it   Step  1 - Add following snippet to config file   lt configuration gt      lt runtime gt         lt legacyCorruptedStateExceptionsPolicy enabled  true    gt      lt  runtime gt   lt  configuration gt    Step  2  Add -    HandleProcessCorruptedStateExceptions    SecurityCritical    on the top of function you are tying catch the exception  source  http   www gisremotesensing com 2017 03 catch-exception-attempted-to-read-or html

User · Answer

You can try using AppDomain UnhandledException and see if that lets you catch it     EDIT   Here is some more information that might be useful  it s a long read

User · Answer

Add the following in the config file  and it will be caught in try catch block  Word of caution    try to avoid this situation  as this means some kind of violation is happening    lt configuration gt      lt runtime gt         lt legacyCorruptedStateExceptionsPolicy enabled  true    gt      lt  runtime gt   lt  configuration gt

[c#] How to handle AccessViolationException

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