Question

I would like to show only show part of the full exception and stacktrace.
I am currently calling ex.ToString() on the exception but I notice there are “duplicate” stacktrace entries.

The only thing I can think of is to parse the string for duplicate strings ignoring the line #. I guess I will have to figure out a regex pattern.

E.g.: in the stacktrace there is “ProcessTeleformFiles.ProcessExpTableRecord(…” listed twice but with different line #’s.

I use the try catch block in almost every single c# 4.0 method I write.

try
catch (Exception)
{
  throw;
}

And then when I want to raise a custom error I do this

try 
catch (Exception ex)
{
  throw new Exception("my custom message", ex);
}

Then at the root level of code I basically show and/or log the error like so:

try 
catch (Exception ex)
{
  MessageBox.Show("Exception found: " + ex.ToString();
}

However the stacktrace can look like this:

Error was logged: Error in ProcessExp() method.
Exception found: System.Exception: Error found in Database: C:\MyDatabase.mdb
 ---> System.Exception: Error found in Table: MyTable
 ---> System.Exception: Error found in TableID: 1
 ---> System.Data.OleDb.OleDbException: Could not find output table 'testtable'.
   at System.Data.OleDb.OleDbCommand.ExecuteCommandTextErrorHandling(OleDbHResult hr)
   at System.Data.OleDb.OleDbCommand.ExecuteCommandTextForSingleResult(tagDBPARAMS dbParams, Object& executeResult)
   at System.Data.OleDb.OleDbCommand.ExecuteCommandText(Object& executeResult)
   at System.Data.OleDb.OleDbCommand.ExecuteCommand(CommandBehavior behavior, Object& executeResult)
   at System.Data.OleDb.OleDbCommand.ExecuteReaderInternal(CommandBehavior behavior, String method)
   at System.Data.OleDb.OleDbCommand.ExecuteScalar()
   at MiscOleDbFns.Querys.RunExecuteScaler(OleDbConnection Conn, String QueryString, Object[] ParamValues) in C:\Document Files\DotNet common libraries\src 4.0\misclibrary_src\source\MiscOleDbFns.cs:line 247
   at MiscOleDbFns.Querys.RunExecuteScalerAndGetAutoNumFromQuery(OleDbConnection Conn, String QueryString, Object[] ParamValues) in C:\Document Files\DotNet common libraries\src 4.0\misclibrary_src\source\MiscOleDbFns.cs:line 271
   at ProcessTeleformFiles.InsertExpSummaryFilesRec(OleDbConnection Conn, Boolean LogFile, RcdExpSummaryFiles Rcd) in C:\Document Files\Projects and notes\VS 2010\Projects\OrganizeTeleformFiles\source\OrganizeTeleformFiles\ProcessFiles.cs:line 622
   at ProcessTeleformFiles.FindFileInList(OleDbConnection conSystemDB, String sCopyToDBFolderExp, Boolean isLogFile, Boolean isCopyFile, Boolean isDeleteFile, RcdExpSummaryFiles recExpSummaryFiles, Dictionary`2 myList) in C:\Document Files\Projects and notes\VS 2010\Projects\OrganizeTeleformFiles\source\OrganizeTeleformFiles\ProcessFiles.cs:line 1216
   at ProcessTeleformFiles.ProcessExpTableRecordSusFiles(OleDbConnection conSystemDB, String sCopyToDBFolderExp, OleDbDataReader Read, RcdSchemaFlds recSchemaFlds, RcdExpSummary recExpSummary, String& tct) in C:\Document Files\Projects and notes\VS 2010\Projects\OrganizeTeleformFiles\source\OrganizeTeleformFiles\ProcessFiles.cs:line 1257
   at ProcessTeleformFiles.ProcessExpTableRecord(OleDbConnection conSystemDB, String sCopyToDBFolderExp, OleDbDataReader Read, RcdSchemaFlds recSchemaFlds, RcdExpSummary recExpSummary) in C:\Document Files\Projects and notes\VS 2010\Projects\OrganizeTeleformFiles\source\OrganizeTeleformFiles\ProcessFiles.cs:line 965
   --- End of inner exception stack trace ---
   at ProcessTeleformFiles.ProcessExpTableRecord(OleDbConnection conSystemDB, String sCopyToDBFolderExp, OleDbDataReader Read, RcdSchemaFlds recSchemaFlds, RcdExpSummary recExpSummary) in C:\Document Files\Projects and notes\VS 2010\Projects\OrganizeTeleformFiles\source\OrganizeTeleformFiles\ProcessFiles.cs:line 982
   at ProcessTeleformFiles.ProcessExpDatabaseTable(OleDbConnection conSystemDB, OleDbConnection ConnExpDb, String sCopyToDBFolderExp, String mdbPath, String sTable, BackgroundWorker worker, DoWorkEventArgs workerEvents) in C:\Document Files\Projects and notes\VS 2010\Projects\OrganizeTeleformFiles\source\OrganizeTeleformFiles\ProcessFiles.cs:line 242
   --- End of inner exception stack trace ---
   at ProcessTeleformFiles.ProcessExpDatabaseTable(OleDbConnection conSystemDB, OleDbConnection ConnExpDb, String sCopyToDBFolderExp, String mdbPath, String sTable, BackgroundWorker worker, DoWorkEventArgs workerEvents) in C:\Document Files\Projects and notes\VS 2010\Projects\OrganizeTeleformFiles\source\OrganizeTeleformFiles\ProcessFiles.cs:line 250
   at ProcessTeleformFiles.ProcessExpDatabase(OleDbConnection conSystemDB, String mdbPath, BackgroundWorker worker, DoWorkEventArgs workerEvents) in C:\Document Files\Projects and notes\VS 2010\Projects\OrganizeTeleformFiles\source\OrganizeTeleformFiles\ProcessFiles.cs:line 161
   --- End of inner exception stack trace ---
   at ProcessTeleformFiles.ProcessExpDatabase(OleDbConnection conSystemDB, String mdbPath, BackgroundWorker worker, DoWorkEventArgs workerEvents) in C:\Document Files\Projects and notes\VS 2010\Projects\OrganizeTeleformFiles\source\OrganizeTeleformFiles\ProcessFiles.cs:line 174
   at ProcessTeleformFiles.ProcessExp(BackgroundWorker worker, DoWorkEventArgs workerEvents) in C:\Document Files\Projects and notes\VS 2010\Projects\OrganizeTeleformFiles\source\OrganizeTeleformFiles\ProcessFiles.cs:line 74

Whereas I would like the error message to not have any duplicate messages; more like this:

Error was logged: Error in ProcessExp() method.
Exception found: System.Exception: Error found in Database: C:\MyDatabase.mdb
 ---> System.Exception: Error found in Table: MyTable
 ---> System.Exception: Error found in TableID: 1
 ---> System.Data.OleDb.OleDbException: Could not find output table 'testtable'.

at MiscOleDbFns.Querys.RunExecuteScaler(OleDbConnection Conn, String QueryString, Object[] ParamValues) in C:\Document Files\DotNet common libraries\src 4.0\misclibrary_src\source\MiscOleDbFns.cs:line 247
   at MiscOleDbFns.Querys.RunExecuteScalerAndGetAutoNumFromQuery(OleDbConnection Conn, String QueryString, Object[] ParamValues) in C:\Document Files\DotNet common libraries\src 4.0\misclibrary_src\source\MiscOleDbFns.cs:line 271
   at ProcessTeleformFiles.InsertExpSummaryFilesRec(OleDbConnection Conn, Boolean LogFile, RcdExpSummaryFiles Rcd) in C:\Document Files\Projects and notes\VS 2010\Projects\OrganizeTeleformFiles\source\OrganizeTeleformFiles\ProcessFiles.cs:line 622
   at ProcessTeleformFiles.FindFileInList(OleDbConnection conSystemDB, String sCopyToDBFolderExp, Boolean isLogFile, Boolean isCopyFile, Boolean isDeleteFile, RcdExpSummaryFiles recExpSummaryFiles, Dictionary`2 myList) in C:\Document Files\Projects and notes\VS 2010\Projects\OrganizeTeleformFiles\source\OrganizeTeleformFiles\ProcessFiles.cs:line 1216
   at ProcessTeleformFiles.ProcessExpTableRecordSusFiles(OleDbConnection conSystemDB, String sCopyToDBFolderExp, OleDbDataReader Read, RcdSchemaFlds recSchemaFlds, RcdExpSummary recExpSummary, String& tct) in C:\Document Files\Projects and notes\VS 2010\Projects\OrganizeTeleformFiles\source\OrganizeTeleformFiles\ProcessFiles.cs:line 1257
   at ProcessTeleformFiles.ProcessExpTableRecord(OleDbConnection conSystemDB, String sCopyToDBFolderExp, OleDbDataReader Read, RcdSchemaFlds recSchemaFlds, RcdExpSummary recExpSummary) in C:\Document Files\Projects and notes\VS 2010\Projects\OrganizeTeleformFiles\source\OrganizeTeleformFiles\ProcessFiles.cs:line 965
at ProcessTeleformFiles.ProcessExpDatabaseTable(OleDbConnection conSystemDB, OleDbConnection ConnExpDb, String sCopyToDBFolderExp, String mdbPath, String sTable, BackgroundWorker worker, DoWorkEventArgs workerEvents) in C:\Document Files\Projects and notes\VS 2010\Projects\OrganizeTeleformFiles\source\OrganizeTeleformFiles\ProcessFiles.cs:line 242
at ProcessTeleformFiles.ProcessExpDatabase(OleDbConnection conSystemDB, String mdbPath, BackgroundWorker worker, DoWorkEventArgs workerEvents) in C:\Document Files\Projects and notes\VS 2010\Projects\OrganizeTeleformFiles\source\OrganizeTeleformFiles\ProcessFiles.cs:line 161
at ProcessTeleformFiles.ProcessExp(BackgroundWorker worker, DoWorkEventArgs workerEvents) in C:\Document Files\Projects and notes\VS 2010\Projects\OrganizeTeleformFiles\source\OrganizeTeleformFiles\ProcessFiles.cs:line 74

UPDATE:
So way back when, I did remove all the try catches in my code. The only situation I modify the stacktrace now is in one place where I give a more user-friendly simplified output to a user. Internally I always log the full stack. Thanks everyone!

Answer 1

The extra rows in the stack trace are not “duplicates”, they indicate the flow of execution – in this case where the exception was caught and rethrown. If you remove them then you are removing valuable information about what happened which is some day going to cause yourself a world of hurt when you are trying to debug an error and can’t work out what happened.

The solution is simple – don’t wrap each method in a try-catch block. It complicates stack traces (as you have seen), incurs a performance penalty every time the exception is caught and re-thrown and makes it very difficult to catch specific exception types.

There is absolutely no advantage to catching and rethrowing exceptions in each method – just catch it when you can do something useful with it which in your case is at the “root level” where you handle it by showing an error message.