.NET: How to convert Exception to string?

Question

When an exception is thrown (while debugging in the IDE), i have the opportunity to view details of the exception:

But in code if i call exception.ToString() i do not get to see those useful details:

System.Data.SqlClient.SqlException (0x80131904): Could not find stored procedure 'FetchActiveUsers'.   [...snip stack trace...] 

But Visual Studio has some magic where it can copy the exception to the clipboard:

Which gives the useful details:

System.Data.SqlClient.SqlException was unhandled by user code   Message=Could not find stored procedure 'FetchActiveUsers'.   Source=.Net SqlClient Data Provider   ErrorCode=-2146232060   Class=16   LineNumber=1   Number=2812   Procedure=""   Server=vader   State=62   StackTrace:        [...snip stack trace...]   InnerException: 

Well i want that!

What would be the contents of:

String ExceptionToString(Exception ex) {      //todo: Write useful routine     return ex.ToString(); } 

that can accomplish the same magic. Is there a .NET function built in somewhere? Does Exception have a secret method somewhere to convert it to a string?

Answer 1

ErrorCode is specific to ExternalException, not Exception and LineNumber and Number are specific to SqlException, not Exception. Therefore, the only way to get these properties from a general extension method on Exception is to use reflection to iterate over all of the public properties.

So you'll have to say something like:

public static string GetExceptionDetails(this Exception exception) {     var properties = exception.GetType()                             .GetProperties();     var fields = properties                      .Select(property => new {                           Name = property.Name,                          Value = property.GetValue(exception, null)                      })                      .Select(x => String.Format(                          "{0} = {1}",                          x.Name,                          x.Value != null ? x.Value.ToString() : String.Empty                      ));     return String.Join("\n", fields); } 

(Not tested for compliation issues.)

.NET 2.0 compatible answer:

public static string GetExceptionDetails(this Exception exception)  {     PropertyInfo[] properties = exception.GetType()                             .GetProperties();     List<string> fields = new List<string>();     foreach(PropertyInfo property in properties) {         object value = property.GetValue(exception, null);         fields.Add(String.Format(                          "{0} = {1}",                          property.Name,                          value != null ? value.ToString() : String.Empty         ));         }              return String.Join("\n", fields.ToArray()); } 

Answer 2

I first tried Jason's answer (at the top), which worked pretty well, but I also wanted:

• To loop iteratively through inner exceptions and indent them.
• Ignore null properties and increases readability of the output.
• It includes the metadata in the Data property. (if any) but excludes the Data property itself. (its useless).

I now use this:

    public static void WriteExceptionDetails(Exception exception, StringBuilder builderToFill, int level)     {         var indent = new string(' ', level);          if (level > 0)         {             builderToFill.AppendLine(indent + "=== INNER EXCEPTION ===");                         }          Action<string> append = (prop) =>             {                 var propInfo = exception.GetType().GetProperty(prop);                 var val = propInfo.GetValue(exception);                  if (val != null)                 {                     builderToFill.AppendFormat("{0}{1}: {2}{3}", indent, prop, val.ToString(), Environment.NewLine);                 }             };          append("Message");         append("HResult");         append("HelpLink");         append("Source");         append("StackTrace");         append("TargetSite");          foreach (DictionaryEntry de in exception.Data)         {             builderToFill.AppendFormat("{0} {1} = {2}{3}", indent, de.Key, de.Value, Environment.NewLine);         }          if (exception.InnerException != null)         {             WriteExceptionDetails(exception.InnerException, builderToFill, ++level);         }     } 

Call like this:

        var builder = new StringBuilder();         WriteExceptionDetails(exception, builder, 0);         return builder.ToString();