c# - Will Dispose() be called in a using statement with a null object?

Yes, Dispose() is only called on non-null objects:

http://msdn.microsoft.com/en-us/library/yh598w02.aspx

The expansion for using checks that the object is not null before calling Dispose on it, so yes, it's safe.

In your case you would get something like:

IDisposable x = GetObject("invalid name"); try {     // etc... } finally {     if(x != null)     {         x.Dispose();     } } 

You should be ok with it:

using ((IDisposable)null) { } 

No exception thrown here.

Side note: don't mistake this with foreach and IEnumerable where an exception will be thrown.

Yes, before Disposing the reference will be null-checked. You can examine yourself by viewing your code in Reflector.

You will not get null reference exception as per my experience. It will be simply ignored.