一、问题描述
问题:The instance of entity type 'xxxx' cannot be tracked because another instance with the same key value for {'Id'} is already being tracked. When attaching existing entities, ensure that only one entity instance with a given key value is attached.
二、解决方案
就是把插入的主键自动赋值即可 id=SequentialGuidGenerator.Instance.Create();
三、示例