Do I need to check this.Disposed inside my get/set for properties, too?

JoeRip

Peer pressure from this group has forced me to implement IDisposable on my class. :omg: My reading of the Dispose() documentation tells me that I should: 1. call Dispose() from my destructor 2. keep a private field (this.disposed), and set it at the end of my Dispose() method 3. "test this.disposed in all of your class' regular methods, and throw an exception if the object is already disposed." (emphasis mine) Does this mean I also need to test this.disposed in the get/set clauses of my properties? Or just in my "regular methods"?

Simon P Stevens

It's kind of an extra check. The world isn't going to end if you don't do the check, but it might add an extra bit of insurance that things aren't going wrong. You should never access a disposed object, it can cause all kinds of problems. The check is only there to ensure that you don't. Personally, I do the check in _public_ methods, but tend not to bother in properties. Although technically you probably should. I'd be interested in other people's opinions on this though.

Simon

PIEBALDconsult

And then what do you do if the instance has been Disposed? " The primary use of this interface is to release unmanaged resources. " When a class doesn't directly use unmanaged resources or a resource that implements IDisposable, then I generally don't implement IDisposable on it. However, implementing IDisposble allows for the class' use in a using statement which is a very handy technique, so in some cases I may implement a Dispose method that does nothing or otherwise leaves the instance in a usable state. So I don't bother with tracking whether or not Dispose has been called on the instance. If Dispose has released some resource, then generally the instance's reference will be null and I can check that and either make a new instance or throw an Exception, as appropriate.

Scott Dorman

JoeRip wrote:

call Dispose() from my destructor

Please make sure you are getting the terminology correct. In C#, the "destructor" is the Dispose() method. If you mean you are calling Dispose() from a method like ~Class(), then you are calling it from a finalizer. If that's the case, you need to triple-check the decision to use a finalizer and make sure that you have everything written correctly as they add a performance penalty to your object and are not trivial to write properly.

JoeRip wrote:

Does this mean I also need to test this.disposed in the get/set clauses of my properties?

A lot of this really depends on why you are implementing IDisposable. If you are maintaining some unmanaged resources or other objects that implement IDisposable then you would want to do this test in your public methods and properties. You can simplify this by creating a single helper method that throws an ObjectDisposedException and then just call that as the first line in any of your methods or properties. If you are using IDisposable simply to get the "using semantics", then you don't need to bother. You can check this article[^] for more information on how to write finalizers and the dispose pattern as well.

Scott Dorman

Microsoft® MVP - Visual C# | MCPD President - Tampa Bay IASA [Blog][Articles][Forum Guidelines]

Hey, hey, hey. Don't be mean. We don't have to be mean because, remember, no matter where you go, there you are. - Buckaroo Banzai