通过业务逻辑初始化Linq到Sql对象-InitializeaLinqtoSqlobjectviabusinesslogic

I think you'd be better off in this instance to use a Factory to create your instances; So anywhere you current have code like:

我认为在这种情况下你最好使用Factory来创建你的实例;所以你目前的任何地方都有如下代码

Product p = new Product();

You would instead have:

你会改为:

Product p = ProductFactory.CreateProduct();

And your CreateProduct() method would look something like:

你的CreateProduct()方法看起来像这样:

public Product CreateProduct()
{
    var p = new Product();
    p.Columns.Add(new ProductColumn {
        Name = "Name", ColumnType = 1
    });
    p.Columns.Add(new ProductColumn {
        Name = "Producer", ColumnType = 2
    });
    return p;
}

There's no built in method for it in the Linq to SQL generated classes. They call OnLoaded specifically when called from the DB, but they do not call anything when it's not. I suspect because there's no way to know for sure...

在Linq to SQL生成的类中没有内置的方法。它们在从DB调用时专门调用OnLoaded,但是当它不是时,它们不会调用任何东西。我怀疑是因为没有办法确切知道......

I'd recommend using the factory approach that Chris suggested.

我建议使用Chris建议的工厂方法。

With LINQ-to-SQL, the entities are largely unaware of the parent data-context - only lazy-loaded members like EntitySet know about this detail. You can identify data-context aware entity-sets by looking at .IsDeferred (assuming it is deferred) - this will be true if a data-context is involved, and false otherwise - but there are further problems:

使用LINQ-to-SQL,实体基本上不知道父数据上下文 - 只有像EntitySet 这样的延迟加载成员才知道这个细节。您可以通过查看.IsDeferred(假设它是延迟的)来识别数据上下文感知实体集 - 如果涉及数据上下文,则为true,否则为false - 但还有其他问题:

• LINQ-to-SQL attaches the data-context (for deferred execution) after the constructur (and OnCreated) has executed

在构造函数(和OnCreated)执行后,LINQ-to-SQL附加数据上下文(用于延迟执行)

• If you add items manually in OnCreated/.ctor(), it breaks when LINQ-to-SQL attempts to attach the data-context

如果在OnCreated / .ctor()中手动添加项目,它会在LINQ-to-SQL尝试附加数据上下文时中断

• LINQ-to-SQL uses the default constructor, meaning that generics/new() etc will also share this code

LINQ-to-SQL使用默认构造函数,这意味着泛型/ new()等也将共享此代码

So unfortunately; no, I don't think you can do this in OnCreated in any sensible way. You could:

不幸的是;不,我认为你不能以任何明智的方式在OnCreated中做到这一点。你可以:

• have a second constructor for this use, that adds the extra items

有这个用途的第二个构造函数,它添加了额外的项目

• use a factory method, i.e. a static .Create() method that builds items correctly

使用工厂方法,即正确构建项目的静态.Create()方法

(since LINQ-to-SQL won't use either of the above itself)

(因为LINQ-to-SQL不会使用上述任何一种)

If you are using the designer -- and I presume you are because you are using partial classes -- you can add the association in the designer and the appropriate columns will get added to your object automatically. MSDN has a reference on how to create associations using the designer work surface.

如果您正在使用设计器 - 我认为您是因为使用了部分类 - 您可以在设计器中添加关联,并且相应的列将自动添加到您的对象中。 MSDN提供了有关如何使用设计器工作表创建关联的参考。