SPEventReceiverDefinition.ContextObjectId Property
Gets or sets the Guid (associated with the ContextType) for the context object.
Assembly: Microsoft.SharePoint (in Microsoft.SharePoint.dll)
Available in Sandboxed Solutions: Yes
Available in SharePoint Online
Property Value
Type: System.GuidGuid that represents the identifier by which to access the context object.
This is the actual SPListItem object, but this property is only used for setting context lookups. For example, the create column action can be retrieved by an id that differs from the id for the create view action, although they are both within the settings context.