Setting the message of a custom Exception without passing it to the base constructor

Question

I want to make a custom Exception in C#, but in theory I do need to do a little parsing first before I can make a human readable ExceptionMessage.

The problem is that the orginal Message can only be set by calling the base constructor of Messsage, so I can't do any parsing in advance.

I tried overring the Message property like this:

public class CustomException : Exception {     string _Message;      public CustomException(dynamic json) : base("Plep")     {         // Some parsing to create a human readable message (simplified)         _Message    = json.message;     }      public override string Message     {         get { return _Message; }     } } 

The problem is that the Visual Studio debugger still shows the message that I've passed into the constructor, Plep in this case.

throw new CustomException( new { message="Show this message" } ) 

results in:

If I leave the base constructor empty it will show a very generic message:

An unhandled exception of type 'App.CustomException' occurred in App.exe

Question

It looks like the Exception Dialog reads some field/property that I don't have any access too. Is there any other way to set a human readable error message outside the base constructor on Exception.

Note that I'm using Visual Studio 2012.

Answer 1

Just put the formatting code into a static method?

public CustomException(dynamic json) : base(HumanReadable(json)) {} private static string HumanReadable(dynamic json) {     return whatever you need to; }