State and Notifications Broker
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State and Notifications Broker provides a mechanism for storing system and application information in the registry and provides a notification system for changes in the stored information. Applications can be made aware of events happening in other applications or with the device itself. For example, a database of the user's music information could automatically be made aware of any artist and album the user plays on Windows Media Player. A power intensive application can be made aware of changes in the strength or charging status of the battery. Or an application that requires Internet connectivity can be made aware of communication connections as the connections are made or dropped.
Notifications can be transient - received by your application only while it is running, or persistent - so that your application will be launched if it is not already running and take action based on an important event.
State and Notification Broker can be used to monitor any registry key in the system. The header file snapi.h contains definitions for the registry key, path, value, and bitmask for all the base notifications that are provided by the system. The general categories of notifications include:
- System state information, such as features present (camera, keyboard), active application, cradled state, battery state.
- Message information, such as count of unread, last received, account info.
- Tasks and appointments information, such as upcoming, overdue, location.
- Windows Media Player information, such as currently playing album, artist.
- Phone information, such as signal information, operator information, call information, multiline information.
- Connections information, related to bluetooth, cellular, network, modem, etc.
State and Notifications Broker was formerly known as Status Store, StatStor, or StatStore.