The CriticalHandle.IsClosed method returns a value indicating whether the System.Runtime.InteropServices.CriticalHandle object's handle is no longer associated with a native resource. This differs from the definition of the CriticalHandle.IsInvalid property, which computes whether a given handle is always considered invalid. The CriticalHandle.IsClosed method returns a true value in the following cases:

• The CriticalHandle.SetHandleAsInvalid method was called.

• The CriticalHandle.Dispose method or CriticalHandle.Close method was called and there are no references to the System.Runtime.InteropServices.CriticalHandle object on other threads.