xxx.Find()
xxx.First()
xxx.ToArray()
...

https://www.zhihu.com/question/388290065

Entity Framework Code First中能夠自動調(diào)用DbContext.ChangeTracker.DetectChanges的方法：

　　? DbSet.Add

　　? DbSet.Find

　　? DbSet.Remove

　　? DbSet.Attach

　　? DbSet.Local

　　? DbContext.SaveChanges

　　? DbContext.GetValidationErrors

　　? DbContext.Entry

　　? DbChangeTracker.Entries

　　? 任何在DbSet上進(jìn)行LINQ的查詢

https://blog.csdn.net/u011127019/article/details/53941235

同一個(gè)上下文中，更新時(shí)，同一實(shí)體只能跟蹤一次，如果再次獲取該對象并且跟蹤，并更新該對象時(shí)就會報(bào)錯(cuò)，因?yàn)閑f無法確定具體那個(gè)跟蹤的對象需要被保存，錯(cuò)誤如下

The instance of entity type 'UserEntity' 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. Consider using 'DbContextOptionsBuilder.EnableSensitiveDataLogging' to see the conflicting key values

https://q.cnblogs.com/q/103473/  此問題中就是Find會跟蹤對象，導(dǎo)致更新失敗