如何在运行时从文本构建LINQ查询? [英] How to build a LINQ query from text at runtime?

问题描述

我有一个

class A {
   public int X;
   public double Y;
   public string Z;
   // and more fields/properties ...
};

和List<A> data，并且可以构建linq查询，例如

and a List<A> data and can build a linq query like e.g.

var q = from a in data where a.X > 20 select new {a.Y, a.Z};

然后dataGridView1.DataSource = q.ToList();在我的DataGridView中显示选择.

Then dataGridView1.DataSource = q.ToList(); displays the selection in my DataGridView.

现在是一个问题，是否可以根据用户在运行时输入的文本来构建查询?喜欢

Now the question, is it possible to build the query from a text the user has entered at runtime? Like

var q = QueryFromText("from a in data where a.X > 20 select new {a.Y, a.Z}");

关键是用户(具有编程技能)可以动态自由地选择显示的数据.

The point being, that the user (having programming skills) can dynamically and freely select the displayed data.

推荐答案

好，您可以使用 Snippy 作为示例.在这种情况下，您需要使用一种接受名为data的List<A>的方法来编译用户代码.我的经验是，它可以正常工作，但是可能有点不对劲，特别是在添加适当的引用等方面.

Well, you can use CSharpCodeProvider to compile code at execution time. Have a look at Snippy for an example of this. In this case you'd need to compile the user code in a method which accepts a List<A> called data. My experience is that it works, but it can be slightly fiddly to get right - particularly in terms of adding the appropriate references etc.

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