CqEvent TKey, TResult  getKey Method Pivotal GemFire .NET Client Documentation
Get the key relating to the event. In case of REGION_CLEAR and REGION_INVALIDATE operation, the key will be null.

Namespace: GemStone.GemFire.Cache.Generic
Assembly: GemStone.GemFire.Cache (in GemStone.GemFire.Cache.dll) Version: 8.0.0.0
Syntax

public TKey getKey()
See Also