EF 代码优先 - IsConcurrencyToken()
简单，但对我来说却很神秘：为什么StringPropertyConfiguration（以及所有其他 PropertyConfiguration）类有 2 个重载IsConcurrencyToken()？
第一个：
public StringPropertyConfiguration IsConcurrencyToken()
配置要用作的属性 乐观并发令牌。
第二个：
public StringPropertyConfiguration IsConcurrencyToken(bool?)
配置属性是否 被用作乐观 并发令牌。
为什么你会使用其中一种而不是另一种？在我看来，这两个重载之间没有任何区别（至少在使用它们时没有区别）...
通过使用第一个重载，您会写出类似这样的内容：
modelBuilder.Entity<Author>()
.Property(x => x.Name)
.IsConcurrencyToken();
通过使用第二个重载，您会写出：
modelBuilder.Entity<Author>()
.Property(x => x.Name)
.IsConcurrencyToken(true/false/null);
我错过了什么吗？
Simple, but yet mysterious for me: Why do StringPropertyConfiguration (and all the other PropertyConfiguration) class(es) have 2 overloads for IsConcurrencyToken()?
The first:
public StringPropertyConfiguration IsConcurrencyToken()
Configures the property to be used as
an optimistic concurrency token.
And the second:
public StringPropertyConfiguration IsConcurrencyToken(bool?)
Configures whether or not the property
is to be used as an optimistic
concurrency token.
Why would you use one over the other? As I see it, there's no difference at all between those two overloads (atleast not when working with them)...
By using the first you would write something like:
modelBuilder.Entity<Author>()
.Property(x => x.Name)
.IsConcurrencyToken();
And by using the second you would write:
modelBuilder.Entity<Author>()
.Property(x => x.Name)
.IsConcurrencyToken(true/false/null);
Have I missed something?
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我的观点...
IsConcurrencyToken()默认为 true，以提供一种简单、流畅的方式来定义实体。IsConcurrencyToken(bool?)允许作者明确设置实体的ConcurrencyMode。这对于高级场景非常有用：[ConcurrencyCheck]属性ConcurrencyMode约定最后，我认为
IsConcurrencyToken(false)比IsNotConcurrencyToken()更好。My opinion...
The
IsConcurrencyToken()defaults to true to provide a simple, fluent manner to define the entity.The
IsConcurrencyToken(bool?)allows the author to definitively set theConcurrencyModeof the entity. This is useful for advanced scenarios:[ConcurrencyCheck]attribute on the POCOConcurrencyModebased on some custom conventionFinally, I think
IsConcurrencyToken(false)is better thanIsNotConcurrencyToken().