从 Linq-to-Entities 中选择 Linq-to-XML？

发布于 2025-01-04 22:00:55 字数 706 浏览 0 评论 0原文

在混合 Linq-to-SQL 和 Linq-to-XML 时，我曾经能够执行以下操作：

XElement xml = new XElement("People");

xml.Add(from p in Context.People
        select new XElement("Person",
            new XElement("Id", p.Id),
            new XElement("Name", p.Name)));

在将一些内容转换为 EF 时，我现在遇到此异常：“LINQ to Entities 仅支持无参数构造函数和初始化程序” ”。

这让我相信我现在需要做这样的事情：

XElement xml = new XElement("People");

var peopleResults = Context.People.Select(p => { p.Id, p.Name }).ToList();

xml.Add(from p in peopleResults
        select new XElement("Person",
            new XElement("Id", p.Id),
            new XElement("Name", p.Name)));

这是我现在唯一的选择，还是有另一种更清晰的方式在代码中表达这一点？

原文

In mixing Linq-to-SQL and Linq-to-XML, I used to be able to do something like this:

XElement xml = new XElement("People");

xml.Add(from p in Context.People
        select new XElement("Person",
            new XElement("Id", p.Id),
            new XElement("Name", p.Name)));

In converting some stuff to EF, I now get this exception: "Only parameterless constructors and initializers are supported in LINQ to Entities."

This leads me to believe I now need to do something like this:

XElement xml = new XElement("People");

var peopleResults = Context.People.Select(p => { p.Id, p.Name }).ToList();

xml.Add(from p in peopleResults
        select new XElement("Person",
            new XElement("Id", p.Id),
            new XElement("Name", p.Name)));

Is this my only alternative now, or is there another cleaner way to express this in code?

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少女净妖师 2025-01-11 22:00:55

进行投影时使用 LINQ to Objects。为此，只需预先调用 AsEnumerable() 即可。

XElement xml = new XElement("People");

xml.Add(from p in peopleResults.AsEnumerable()
        select new XElement("Person",
            new XElement("Id", p.Id),
            new XElement("Name", p.Name)));

Use LINQ to Objects when you do the projection. To do that, just call AsEnumerable() beforehand.

XElement xml = new XElement("People");

xml.Add(from p in peopleResults.AsEnumerable()
        select new XElement("Person",
            new XElement("Id", p.Id),
            new XElement("Name", p.Name)));

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请你别敷衍 2025-01-11 22:00:55

做法是正确的。要稍微缩短它，您可以直接在对象上使用 ToList 方法。

XElement xml = new XElement("People");

xml.Add(from p in Context.People.ToList()
        select new XElement("Person",
            new XElement("Id", p.Id),
            new XElement("Name", p.Name)));

The approach is correct. To shorten it slightly you can use the ToList method on the object directly.

XElement xml = new XElement("People");

xml.Add(from p in Context.People.ToList()
        select new XElement("Person",
            new XElement("Id", p.Id),
            new XElement("Name", p.Name)));

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