Exceptions are a primitive type

I hold that Exception is a primitive type, and so using one directly in your code is a common example of Primitive Obsession.

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The antidote is to wrap the primitive in a Whole Value. It's a pretty straightforward transformation when your code looks like this:

- Make a new exception class, typically nested at the current scope.
- Name it based on the message text.
- Parameters to the message become parameters to the constructor and properties on the new class.
- Override the "Message" property to hold the string.Format() call.

Like this:

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Like all good design moves, this helps testing.

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Note that in the 2nd example, I'm separating "I expect this exception with these properties" from "the exception should be able to format itself like this". There's a nice separation of concerns.