C# 具有匿名类型的OrderBy

我有以下资料：

Context context = new Context();

var persons = context.Persons.Select(x => new { Name = x.Name });   

var mapper = OrderMapper.For(persons).Add("name", x => x.Name);

var result = persons.OrderByWithMapper(mapper);

public static IQueryable<T> OrderByWithMapper<T>(this IQueryable<T> source, OrderMapper<T> mapper) {
   // Method code
}

public class OrderMapper {
  public static OrderMapper<T> For<T>(IEnumerable<T> collection) {
    return new OrderMapper<T>();
  }
}

public class OrderMapper<T> {
}

其中：

• 人员类型为

  IQueryable

• 映射器的类型为

  OrderMapper

• OrderByWithMapper

  如下所示：

  Context context = new Context();
  
  var persons = context.Persons.Select(x => new { Name = x.Name });   
  
  var mapper = OrderMapper.For(persons).Add("name", x => x.Name);
  
  var result = persons.OrderByWithMapper(mapper);
  

  public static IQueryable<T> OrderByWithMapper<T>(this IQueryable<T> source, OrderMapper<T> mapper) {
     // Method code
  }
  

  public class OrderMapper {
    public static OrderMapper<T> For<T>(IEnumerable<T> collection) {
      return new OrderMapper<T>();
    }
  }
  
  public class OrderMapper<T> {
  }
  

但我在尝试创建结果时出错：

 'List<<anonymous type: string Name>>' does not contain a definition for 'OrderByWithMapper'
 and the best extension method overload 'OrderByWithMapper<<anonymous type: 
 string Name>>(IQueryable<<anonymous type: string Name>>, OrderMapper<<anonymous type: string Name>>)' 
 requires a receiver of type 'IQueryable<<anonymous type: string Name>>'

“列表”不包含“OrderByWithMapper”的定义
最好的扩展方法重载“OrderByWithMapper（IQueryable，OrderMapper）”
需要“IQueryable”类型的接收器

我不确定哪里出了问题，因为EntityFramework中的OrderBy方法可以很好地用于匿名，例如：

public static IOrderedQueryable<TSource> OrderBy<TSource, TKey>(this IQueryable<TSource> source, Expression<Func<TSource, TKey>> keySelector);

public static IOrderedQueryable OrderBy（此IQueryable源、表达式keySelector）；

---

我应该在OrderByWithMapper方法中更改什么以使其适用于匿名类型？

您的扩展方法

OrderByWithMapper（此IQueryable源，OrderMapper映射器）

需要

IQueryable

和

OrderMapper

---

根据错误消息，您正试图在

列表中执行它，以获取有关IQueryable的更多信息。
当然！我错过了第一个查询末尾的ToList（），它将它变成了一个列表。。。