The OpenStateChange event occurs when the Windows Media Player control changes state.
Windows Media Player can go through several open states while it attempts to open a file over a network, such as locating the server, connecting to the server, and opening the file. This event will be fired each time the open state changes.
Windows Media Player states are not guaranteed to occur in any particular order. Furthermore, not every state necessarily occurs during a sequence of events. You should not write code that relies upon state order.