En RelationshipManager kan inte returneras för det här objektet. En RelationshipManager kan bara returneras för objekt som antingen spåras av ObjectStateManager eller som implementerar IEntityWithRelationships.
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English version
A RelationshipManager cannot be returned for this object. A RelationshipManager can only be returned for objects that are either tracked by the ObjectStateManager or that implement IEntityWithRelationships.
.Net Framework