Custom Exception Handling Event

[fastbike]

Allow custom exception handling for application defined Exception types.

E.g. I have a custom exception (EFHIRException) that has additional properties and a method to render it as an XML string. I have added a function "AsXMLString" to the exception class.
I have made a change to the TMVCEngine class and added an event property to surface the Exception prior to standard exception handling occurring.

TMVCExceptionEvent = procedure(E: Exception; SelectedController: TMVCController; WebContext: TWebContext; var ExceptionHandled: Boolean) of object;

Assign an event handler to the MVCEngine object and set ExceptionHandled to true if your code has handled/rendered the Exception.

I will post proposed changes and a simple sample project.

Looking for feedback and improvements, and hopefully a git pull request into the code base.

[fastbike]

Issue191.zip
MVCEngine change and Sample Project attached

[danieleteti]

Basic idea and a refactored sample has been merged into the repo. Thank you for your contribution.