使用Linq.Ex pression动态拉姆达访问嵌套的性质 [英] Access nested properties with dynamic lambda using Linq.Expression

问题描述

让我们假设我有两个类：

Let's assume that I have two classes:

class person
{
    int ID
    string name
    Address address
}
class address
{
    int ID
    string street
    string country
}

这些类都或多或少给出，它们通过NHibernate的映射是诚实的：）

These classes are more or less given, they are mapped via nHibernate to be honest :)

在一个网格（ datatables.net 为基础），我想有一个类型无关的排序。

In a grid (datatables.net as base) I would like to have a type-independent sorting.

因此​​，我创建了一个lambda前pression：

Therefore I created a lambda expression:

  var param = Expression.Parameter(typeof(T), typeof(T).Name);
  var sortExpression = Expression.Lambda<Func<T, object>>
                              (Expression.Convert(Expression.Property(param, "Property to sort"), typeof(object)), param);

如果我通过人的T型和替换属性进行排序和名，它工作正常（创建了一个正确的拉姆达）。如果要排序的属性为address.street将无法正常工作，丢了我以下错误：

If I pass Person as Type T and replace the "Property to sort" with "name" it works fine (creates a correct lambda). If the Property to sort is "address.street" it won't work, throw me the following error:

Property 'address.street' is not defined for type 'person'

我只看到一个解决方案，到目前为止，但不太清楚......我想尝试拆分包含属性名称字符串（斯普利特）。

I see only one solution so far, but not clear enough... I would try to split the string which contains the Property-Name (split by .)

谁能给一个更好的解决方案？我需要的SORTEX pression添加到一个IQueryable对象 query.OrderBy（SORTEX pression）。

Can anyone give a better solution? I need to add the sortExpression to an IQueryable object query.OrderBy(sortExpression).

不知道如果我的标题是明确的，请继续前进并加以纠正。

Not sure if my title is clear, please go ahead and correct it.

先谢谢了。

推荐答案

什么是不明确？

您必须拆分，然后使用：

You have to split it and then use:

Expression.Property(Expression.Property(param, "address"), "street")

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