Exception to throw when expecting a null value?

问题

If I am expecting a null value and get a defined value (within a getter of a property) and want to throw an exception, what would be the proper way to do this in csharp? Is there anything defined already that makes sense in this situation?

回答1:

My guess would be:

throw new
    ArgumentException("Parameter was expected to be null, value was provided.");

ArgumentOutOfRangeException might also work, but is typically used when there is a well defined range rather than null vs. not null.

回答2:

I would probably use ArgumentOutOfRangeException

回答3:

I've seen InvalidOperationException used, as in the context of trying to set something twice. For example,

if(displayMessage != null)
  throw new InvalidOperationException("The display message may not be set more than once.");

displayMessage = myAwesomeMessage;

来源：https://stackoverflow.com/questions/3400818/exception-to-throw-when-expecting-a-null-value