复杂的Linq查询来选择列表项目与另一个列表属性包含值

Question

我想获得过滤器列表上的2个属性，其中第一个属性是一个值，第二个属性是另一个列表的对象包含一定的值属性。

如下面我想获得的List<Class1>一个列表，其中field1 == "f1"和Field3包含Class2中的项目，其中财产c2 == 2

我可以用得到的SelectMany接近但是这给List<Class2>，而不是父母的Class1。

这可能吗？

示例代码如下

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 

namespace ConsoleApplication2 
{ 
    class Program 
    { 
     static void Main(string[] args) 
     { 
      Class2 c2_1 = new Class2() {c1 = "c1", c2 = 2}; 
      Class2 c2_2 = new Class2() {c1 = "c2", c2 = 4}; 
      Class2 c2_3 = new Class2() { c1 = "c3", c2 = 1 }; 
      Class2 c2_4 = new Class2() { c1 = "c4", c2 = 3 }; 
      Class2 c2_5 = new Class2() { c1 = "c5", c2 = 2 }; 
      Class2 c2_6= new Class2() { c1 = "c6", c2 = 4 }; 

      List<Class1> class1List = new List<Class1>() 
      { 
       new Class1() { field1 = "f1", field2 = "Want This Class", field3 = new List<Class2>() { c2_1, c2_2 } }, 
       new Class1() { field1 = "f1", field2 = "Do Not Want This Class", field3 = new List<Class2>() { c2_3, c2_4 } }, 
       new Class1() { field1 = "f1", field2 = "Want This Class", field3 = new List<Class2>() { c2_5, c2_6} } 
      }; 

      //Want list of Class1 where field1 == "f1" && field3 List contains an item with property c2 == 2 (Should be list of 2 Class1 items) 

      //Doesn't work 
      //var list1 = class1List.Where(x => x.field1 == "f1" && x.field3.c2) 

      //Close, but gives a list of Class2 items but need list of parent Class1 
      var list2 = class1List.Where(x => x.field1 == "f1").SelectMany(x => x.field3.Where(d => d.c2 == 2)).ToList(); 


     } 



    } 

    public class Class1 
    { 
     public string field1 { get; set; } 
     public string field2 { get; set; } 

     public List<Class2> field3 { get; set; } 
    } 
    public class Class2 
    { 
     public string c1 { get; set; } 
     public int c2 { get; set; } 
    } 
} 

Answer 1

您可以在field3申请Any()返回true如果field3包含至少一个项目与c2值等于2：

.... 
var list2 = class1List.Where(x => x.field1 == "f1" && 
            x.field3.Any(d => d.c2 == 2)) 
         .ToList(); 
foreach (var class1 in list2) 
{ 
    Console.WriteLine(class1.field2); 
} 

输出：

Want This Class 
Want This Class