OPC Studio User's Guide and Reference
State Persistence
Concepts > OPC Data Client Concepts > OPC Data Client Development Models > Imperative Programming Model > Imperative Programming Operation Model > State Persistence

The EasyDAClient and EasyAEClient components support a limited form of cache persistency. The information cached for browse path and item Id resolution, which is normally kept in memory and is thus lost when the program is restarted, can be persisted to disk and retrieved again, improving performance. This functionality is turned off by default, but can be enabled using the InstanceParameters.EnableCachePersistence property. The information persisted per-user, and the storage place can further be distinguished by setting the InstanceParameters.PersistenceKey property.

When you enable state persistence, you are responsible for developing the code in such a way that no more than one component with the same persistence key exists at any given time. Otherwise, the multiple instances of the component will overwrite the persisted state information, defeating the purpose of the mechanism.

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