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[英]EF: The instance of entity type X cannot be tracked because another instance of this type with the same key is already being tracked
[英]EF Core already tracked entity with same id
我不知道如何摆脱错误:
无法跟踪实体类型“关系”的实例,因为已在跟踪另一个具有键值“{Id: 26}”的实例。 附加现有实体时,请确保仅附加一个具有给定键值的实体实例。
我尝试将实体从上下文中分离出来,但即使这样也不能阻止这个错误的发生。 有人可以向我指出我做错了什么吗?
服务:
private async Task<int> EditAsync(RelationModel model)
{
RelationEntity entity = _mapper.ToEntity(model);
RelationEntity oldRelation = await _relationRepository.GetRelationAsync(entity.Id);
_relationRepository.UpdateRelation(oldRelation, entity);
await _relationRepository.SaveAsync();
return entity.Id;
}
存储库:
public void UpdateRelation(Relation oldRelation, Relation relation)
{
if (oldRelation != null)
{
// Detach
Context.Entry(oldRelation).State = EntityState.Detached;
// Delete childs
if (oldRelation.Person != null && relation.Person == null)
{
Context.Persons.Remove(oldRelation.Person);
}
if (oldRelation.Customer != null && relation.Customer == null)
{
Context.Customers.Remove(oldRelation.Customer);
}
if (oldRelation.Supplier != null && relation.Supplier == null)
{
Context.Suppliers.Remove(oldRelation.Supplier);
}
if (oldRelation.Employee != null && relation.Employee == null)
{
Context.Employees.Remove(oldRelation.Employee);
}
// Update parent
Context.Relations.Update(relation); // <-- error occurs
}
}
Relation
实体:
public class Relation : BaseEntity<int>
{
public string Code { get; set; }
public int? PersonId { get; set; }
public Person Person { get; set; }
public int? CompanyId { get; set; }
public Company Company { get; set; }
public int? CustomerId { get; set; }
public Customer Customer { get; set; }
public int? SupplierId { get; set; }
public Supplier Supplier { get; set; }
public int? EmployeeId { get; set; }
public Employee Employee { get; set; }
public ICollection<RelationRelations> ParentRelations { get; set; }
public ICollection<RelationRelations> ContactPersons { get; set; }
public ICollection<RelationContactMethod> ContactMethods { get; set; }
public ICollection<RelationAddress> Addresses { get; set; }
}
更新
我尝试更换
Context.Relations.Update(relation);
和
Context.Entry(oldRelation).CurrentValues.SetValues(relation);
但是我在Relation
实体上的所有属性都没有更新。
更新 2
运行以下代码时
Context.Entry(oldRelation).CurrentValues.SetValues(relation);
Context.SaveChanges();
我可以看到旧关系已使用新值进行了更新,但它们并未应用于数据库……这是为什么呢?
多年来,我一直在使用此代码而不是“更新”,一切都得到了正确的更新,而且我从来没有出现任何错误。
尝试对 EF 使用通用代码绝不是一个好主意。 如果要更新几个类,请尝试以这种方式 select:
var oldrelation = Context.Relations
.Include(i=> i.Person)
.Include(i=> i.Company)
...
.FirstOrDefault(i=> i.Id=entity.Id);
代替
Context.Relations.Update(relation);
和
Context.Entry(oldRelation).CurrentValues.SetValues(relation);
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