Dispose called by Component.Finalize() on non-UI thread - does this mean Dispose methods always have to be thread safe?

I checked which thread my Dispose(bool) methods get called on. When the app is running, it is always the UI thread that calls Dispose, say when clicking on the [x] to close a Form. But when I close the whole app, many Dispose methods get called on a (single) different thread. When I dump the stack trace, I see that they all get called from System.ComponentModel.Component.Finalize().

Does that mean all my Dispose methods need to be made thread-safe? Or is WinForms guaranteeing that the UI thread won't touch these objects any more and does it also estab开发者_Python百科lish some kind of "happened-before" relationship between the UI thread and the one that's now finalizing?

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Yes, the finalizer works on a separate thread. Usually this is no problem, because when an Object is finalized it is not reachable by any user thread (like the UI thread) anymore. So, you usually do not have to be thread-safe within your finalizer.