如何使用Linq和ASP.Net Forms在多个表之间编写连接(How do I write Joins between multiple tables with Linq and ASP.Net

如何使用Linq和ASP.Net Forms在多个表之间编写连接(How do I write Joins between multiple tables with Linq and ASP.Net Forms)

我已经实现了一个有效的解决方案，但LINQ对我来说是一件好事，我很难找到所需的信息。

这是我有的：

var prodCat = from pc in db.ProductCategories where pc.Category == Int32.Parse(CategoriesDropper.SelectedValue) select pc; List<int> productIds = new List<int>(); foreach (var pc in prodCat) { productIds.Add(pc.Product); } var products = from p in db.Products where productIds.Contains(p.Id) select p; ProductsGridView.DataSource = products; ProductsGridView.DataBind();

理想情况下，我想用一个选择而不是两个选择来获得相同的结果。

I've implemented a solution that works, but LINQ is a something nre for me and I am struggling to find the required information.

Here is what I have:

var prodCat = from pc in db.ProductCategories where pc.Category == Int32.Parse(CategoriesDropper.SelectedValue) select pc; List<int> productIds = new List<int>(); foreach (var pc in prodCat) { productIds.Add(pc.Product); } var products = from p in db.Products where productIds.Contains(p.Id) select p; ProductsGridView.DataSource = products; ProductsGridView.DataBind();

Ideally I would like to achieve the same result with a single select rather than two.

最满意答案

var products = from pc in db.ProductCategories join p in db.Products on pc.Product equals p.Id where pc.Category == Int32.Parse(CategoriesDropper.SelectedValue) select p; ProductsGridView.DataSource = products; ProductsGridView.DataBind();

有关Visual Studio 2010的信息 ，请参阅CQ中的LINQ - Join Operators以供参考。

希望这可以帮助！

var products = from pc in db.ProductCategories join p in db.Products on pc.Product equals p.Id where pc.Category == Int32.Parse(CategoriesDropper.SelectedValue) select p; ProductsGridView.DataSource = products; ProductsGridView.DataBind();

See LINQ - Join Operators in C# for Visual Studio 2010 for reference.

Hope this helps!