[英]Entity Model - How to insert / update data which involves navigational properties
I am using Entity Framework, WebForms, .Net Framework 3.5 I want to update a record in database using entity model which involves updating a foreign key too, which has become a navigational property in Entity. 我正在使用Entity Framework,WebForms,.Net Framework 3.5,我想使用实体模型更新数据库中的记录,该模型也涉及到更新外键,外键已成为Entity中的导航属性。
How can I do that? 我怎样才能做到这一点? I have seen a way which involves another query like 我已经看到一种涉及另一个查询的方式
Product p = new Product{
ID = 5,
Name = "Bovril",
Category = ctx.Categories.First( c => c.ID == 5)
};
ctx.AddToProducts(p);
ctx.SaveChanges();
How can I do that without going to DB ? 我如何在不使用DB的情况下做到这一点?
Try this (this works with EF 4 so hopefully it will work with EF 1 as well): 尝试以下操作(此方法可用于EF 4,因此希望它也可用于EF 1):
Category c = new Category
{
ID = 5
};
ctx.AttachTo("Categories", c);
Product p = new Product
{
ID = 5,
Name = "Bovril"
};
ctx.AddToProducts(p);
p.Category = c;
ctx.SaveChanges();
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