方法的返回值正在修改作为方法参数传递的对象

Question

I'm in a situation where I am writing a method where the return value directly modifies a class which was used to supply paramaters to the method.

Computer.MatchingPassword = PasswordFinder.Find(Computer.Name, PasswordList)

Does assigning to a property of a passed parameter like this have any hazards?

Answer 1

Technically, your code sample doesn't assign to the parameter, since you passed a property of the Computer object.

In other words, you only gave the function "name", so assigning to a different property of the same object would have no effect.

Now, in the more general case, you are still safe. Even passing the whole object, by the time you assign the return value the method has already completed . Any changes you make won't do anything.

In other words, the following code is functionally equivalent:

string password = PasswordFinder.Find(Computer.Name, PasswordList);
Computer.MatchingPassword = password;

Clearly no problems there. This is true even if it was passed by ref , as again, the method is totally done with the object, so any changes to it won't matter.