附加具有关联的实体以进行修改

发布于 2024-10-20 20:22:01 字数 228 浏览 7 评论 0原文

我将修改具有关联集合的分离实体，例如：

人员和地址是 POCO。

当我附加实体并保存更改时，未检测到集合更改，如何更新人员的地址（添加和删除的项目）？

我需要手动跟踪我的收藏吗？

编辑

分离 POCO 的同步必须手动... EF 无意合并解决方案集合（导航属性和关系）:(

我比较当前集合和原始集合，并检测差异

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安稳善良 2024-10-27 20:22:01

如果您使用的是实体框架（我假设您使用的是实体框架，因为您将其列为问题上的标签），那么对象仅在实体上下文生成时跟踪它们的更改。

User someUser = dbEntities.Users.Single(x => x.Username == "test");
someUser.Name = "changed name";
db.SaveChanges();

该代码将检测更改并保留它们。

User someUser = new User()
{
    Username = "test" //assuming there is already user called test in the database.
}

以这种方式创建用户将不允许 EF 上下文检测到更改。相反，您需要从数据库加载实体，更新它，然后保留更改。

string username = "test";
User someUser = db.Users.Single(x => x.Username == username);
TryUpdateModel(someUser, valueProvider); //valueProvider is usually a form collection of some sort, but could be anything that implements IValueProvider.
db.SaveChanges();

这将允许您拉入实体、更新它并保存更改。

If you are using Entity Framework, which I assume you are since you listed it as a tag on your question, then objects only track their changes when they are generated by the entity context.

User someUser = dbEntities.Users.Single(x => x.Username == "test");
someUser.Name = "changed name";
db.SaveChanges();

That code will detect changes and persist them.

User someUser = new User()
{
    Username = "test" //assuming there is already user called test in the database.
}

Creating the user this way will not allow the EF context to detect the changes. Instead you will need to load the entity from the database, update it, and then persist the changes.

string username = "test";
User someUser = db.Users.Single(x => x.Username == username);
TryUpdateModel(someUser, valueProvider); //valueProvider is usually a form collection of some sort, but could be anything that implements IValueProvider.
db.SaveChanges();

This will allow you to pull in an entity, update it, and save the changes.

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