C# Cookbook

5.10. Preventing Unhandled Exceptions

Problem

You need to make absolutely sure that every exception thrown by your application is handled and that no exception is bubbled up past the outermost exception handler. Hackers often use these types of exceptions to aid in their analysis of the vulnerabilities of an application.

Solution

Place try-catch or try-catch-finally blocks in strategic places in your application. In addition, use the exception event handler as a final line of defense against unhandled exceptions.

Discussion

If an exception occurs and is not handled, it will cause your application to shut down prematurely. This can leave data in an unstable state, which may only be able to be rectified by manual intervention—meaning that you could be spending a long night cleaning up the data by hand. To minimize the damage, you can place exception handlers in strategic locations throughout your code.

The most obvious location to place exception handling code is inside of the Main method. The Main method is the entry point to executables (files with an .exe extension). Therefore, if any exceptions occur inside your executable, the CLR starts looking for an exception handler, starting at the location where the exception occurred. If none are found, the CLR walks the stack until one is found; each method on the stack is examined in turn to determine whether an exception handler exists. If no exception handlers are found in the final method in the stack, the exception is considered unhandled ...