8.4. Displaying User-Friendly Error Messages
You want the event-handling methods described in this chapter to write detailed messages to an error log for use in debugging your application, but you want to display friendly, informative messages to the user.
Create a custom exception class that includes a property to hold the user-friendly message, and when an error occurs, instantiate a new exception object of the custom type in the
Catch block of your error-handling code, set the property of the exception to the desired message, and throw the new exception.
Use the .NET language of your choice to create the custom exception class by deriving from
System.ApplicationException and adding a property to hold the userfriendly message, giving it a name like
In the code-behind for the ASP.NET pages of your application that need to perform error handling, use the .NET language of your choice to:
Catchblock of methods where informative messages are useful, instantiate a new exception object of your custom class type, set the
userFriendlyMessageproperty to the desired message, and throw the new exception.
Application_Errorevent handler, write the detailed information provided by the exception object to the event log and display the message contained in the
userFriendlyMessageproperty of the exception on a common error message page.