Exception Message vs Exception ToString

Question

I have code that is logging Exception Message  However  I read an article which states that it s better to use Exception ToString    With the latter  you retain more crucial information about the error   Is this true  and is it safe to go ahead and replace all code logging Exception Message   I m also using an XML based layout for log4net  Is it possible that Exception ToString   may contain invalid XML characters  which may cause issues

User · Answer

In terms of the XML format for log4net  you need not worry about ex ToString   for the logs  Simply pass the exception object itself and log4net does the rest do give you all of the details in its pre-configured XML format  The only thing I run into on occasion is new line formatting  but that s when I m reading the files raw  Otherwise parsing the XML works great

User · Answer

Converting the WHOLE Exception To a String  Calling Exception ToString   gives you more information than just using the Exception Message property  However  even this still leaves out lots of information  including    The Data collection property found on all exceptions  Any other custom properties added to the exception    There are times when you want to capture this extra information  The code below handles the above scenarios  It also writes out the properties of the exceptions in a nice order  It s using C  7 but should be very easy for you to convert to older versions if necessary  See also this related answer   public static class ExceptionExtensions       public static string ToDetailedString this Exception exception    gt          ToDetailedString exception  ExceptionOptions Default        public static string ToDetailedString this Exception exception  ExceptionOptions options                if  exception    null                        throw new ArgumentNullException nameof exception                        var stringBuilder   new StringBuilder             AppendValue stringBuilder   Type   exception GetType   FullName  options            foreach  PropertyInfo property in exception              GetType                GetProperties                OrderByDescending x   gt  string Equals x Name  nameof exception Message   StringComparison Ordinal                ThenByDescending x   gt  string Equals x Name  nameof exception Source   StringComparison Ordinal                ThenBy x   gt  string Equals x Name  nameof exception InnerException   StringComparison Ordinal                ThenBy x   gt  string Equals x Name  nameof AggregateException InnerExceptions   StringComparison Ordinal                          var value   property GetValue exception  null               if  value    null  amp  amp  options OmitNullProperties                                if  options OmitNullProperties                                        continue                                    else                                       value   string Empty                                               AppendValue stringBuilder  property Name  value  options                      return stringBuilder ToString   TrimEnd   r     n               private static void AppendCollection          StringBuilder stringBuilder          string propertyName          IEnumerable collection          ExceptionOptions options                        stringBuilder AppendLine    options Indent  propertyName                    var innerOptions   new ExceptionOptions options  options CurrentIndentLevel   1                var i   0              foreach  var item in collection                                var innerPropertyName       i                      if  item is Exception                                        var innerException    Exception item                      AppendException                          stringBuilder                          innerPropertyName                          innerException                          innerOptions                                     else                                       AppendValue                          stringBuilder                          innerPropertyName                          item                          innerOptions                                        i                               private static void AppendException          StringBuilder stringBuilder          string propertyName          Exception exception          ExceptionOptions options                var innerExceptionString   ToDetailedString              exception               new ExceptionOptions options  options CurrentIndentLevel   1             stringBuilder AppendLine    options Indent  propertyName               stringBuilder AppendLine innerExceptionString              private static string IndentString string value  ExceptionOptions options                return value Replace Environment NewLine  Environment NewLine   options Indent              private static void AppendValue          StringBuilder stringBuilder          string propertyName          object value          ExceptionOptions options                if  value is DictionaryEntry                        DictionaryEntry dictionaryEntry    DictionaryEntry value              stringBuilder AppendLine    options Indent  propertyName     dictionaryEntry Key     dictionaryEntry Value                       else if  value is Exception                        var innerException    Exception value              AppendException                  stringBuilder                  propertyName                  innerException                  options                     else if  value is IEnumerable  amp  amp    value is string                         var collection    IEnumerable value              if  collection GetEnumerator   MoveNext                                  AppendCollection                      stringBuilder                      propertyName                      collection                      options                                   else                       stringBuilder AppendLine    options Indent  propertyName     value                        public struct ExceptionOptions       public static readonly ExceptionOptions Default   new ExceptionOptions                 CurrentIndentLevel   0          IndentSpaces   4          OmitNullProperties   true             internal ExceptionOptions ExceptionOptions options  int currentIndent                this CurrentIndentLevel   currentIndent          this IndentSpaces   options IndentSpaces          this OmitNullProperties   options OmitNullProperties             internal string Indent   get   return new string      this IndentSpaces   this CurrentIndentLevel            internal int CurrentIndentLevel   get  set         public int IndentSpaces   get  set         public bool OmitNullProperties   get  set        Top Tip - Logging Exceptions  Most people will be using this code for logging  Consider using Serilog with my Serilog Exceptions NuGet package which also logs all properties of an exception but does it faster and without reflection in the majority of cases  Serilog is a very advanced logging framework which is all the rage at the time of writing   Top Tip - Human Readable Stack Traces  You can use the Ben Demystifier NuGet package to get human readable stack traces for your exceptions or the serilog-enrichers-demystify NuGet package if you are using Serilog

User · Answer

Exception Message contains only the message  doh  associated with the exception  Example   Object reference not set to an instance of an object  The Exception ToString   method will give a much more verbose output  containing the exception type  the message  from before   a stack trace  and all of these things again for nested inner exceptions  More precisely  the method returns the following   ToString returns a representation of the current exception that is intended to be understood by humans  Where the exception contains culture-sensitive data  the string representation returned by ToString is required to take into account the current system culture  Although there are no exact requirements for the format of the returned string  it should attempt to reflect the value of the object as perceived by the user  The default implementation of ToString obtains the name of the class that threw the current exception  the message  the result of calling ToString on the inner exception  and the result of calling Environment StackTrace  If any of these members is a null reference  Nothing in Visual Basic   its value is not included in the returned string  If there is no error message or if it is an empty string   quot  quot    then no error message is returned  The name of the inner exception and the stack trace are returned only if they are not a null reference  Nothing in Visual Basic

User · Answer

Well  I d say it depends what you want to see in the logs  doesn t it  If you re happy with what ex Message provides  use that  Otherwise  use ex toString   or even log the stack trace

User · Answer

Depends on the information you need  For debugging the stack trace  amp  inner exception are useful       string message            Exception type     ex GetType     Environment NewLine            Exception message      ex Message   Environment NewLine            Stack trace      ex StackTrace   Environment NewLine      if  ex InnerException    null                message     ---BEGIN InnerException---     Environment NewLine                       Exception type     ex InnerException GetType     Environment NewLine                       Exception message      ex InnerException Message   Environment NewLine                       Stack trace      ex InnerException StackTrace   Environment NewLine                       ---END Inner Exception

User · Answer

I d say  Wim is right  You should use ToString   for logfiles - assuming a technical audience - and Message  if at all  to display to the user   One could argue that even that is not suitable for a user  for every exception type and occurance out there  think of ArgumentExceptions  etc     Also  in addition to the StackTrace  ToString   will include information you will not get otherwise  For example the output of fusion  if enabled to include log messages in exception  messages      Some exception types even include additional information  for example from custom properties  in ToString    but not in the Message

User · Answer

In addition to what s already been said  don t use ToString   on the exception object for displaying to the user  Just the Message property should suffice  or a higher level custom message   In terms of logging purposes  definitely use ToString   on the Exception  not just the Message property  as in most scenarios  you will be left scratching your head where specifically this exception occurred  and what the call stack was  The stacktrace would have told you all that

[c#] Exception.Message vs Exception.ToString()

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