C# Online Compiler | .NET Fiddle

<no name> by Anonymous

using System;
using System.Linq;
using System.Collections.Generic;
					
public class Program
{
	
	public class Item
	{
		public int ParentId {get;set;}
		public int ItemTypeId {get;set;}
		public int? AttachedFileId {get;set;}
		
		public Item(int parentId, int itemTypeId, int? attachedFileId=null)
		{
			this.ParentId = parentId;
			this.ItemTypeId = itemTypeId;
			this.AttachedFileId = attachedFileId;
		}
	}
	
	
	
	public static void Main()
	{
		var _items = new List<Item>()
		{
			new Item(1,3),
			new Item(1,6,1),
			new Item(1,6,2),
			new Item(2,3,3),
			new Item(2,6,3),
			new Item(2,6),
			new Item(3,6,4),
			new Item(3,6,5),
			new Item(4,4,6),
			new Item(4,4,7)
		};
		
		var items = _items
			.GroupBy(x=>x.ParentId)
			.Select(x=>new
					{
						ParentId = x.Key,
						KN = x.Where(_=>_.ItemTypeId == 3).Any() && x.Where(_=>_.ItemTypeId==3).All(_=>_.AttachedFileId!=null),
						KD = x.Where(_=>_.ItemTypeId == 4).Any() && x.Where(_=>_.ItemTypeId==4).All(_=>_.AttachedFileId!=null),
						NC = x.Where(_=>_.ItemTypeId == 6).Any() && x.Where(_=>_.ItemTypeId==6).All(_=>_.AttachedFileId!=null),
					})
			.ToList();
		
		foreach(var i in items)
			Console.WriteLine($"Parent: {i.ParentId}\r\n\tHasKN: {i.KN}\tHasKD: {i.KD}\tHasNC: {i.NC}");
	}
}

 
using System;
using System.Linq;
using System.Collections.Generic;
                    
public class Program
{
    
    public class Item
    {
        public int ParentId {get;set;}
        public int ItemTypeId {get;set;}
        public int? AttachedFileId {get;set;}
        
        public Item(int parentId, int itemTypeId, int? attachedFileId=null)
        {
            this.ParentId = parentId;
            this.ItemTypeId = itemTypeId;
            this.AttachedFileId = attachedFileId;
        }
    }
    
    
    
    public static void Main()
    {
        var _items = new List<Item>()
        {
            new Item(1,3),
            new Item(1,6,1),
            new Item(1,6,2),
            new Item(2,3,3),
            new Item(2,6,3),
            new Item(2,6),
            new Item(3,6,4),
            new Item(3,6,5),
            new Item(4,4,6),
            new Item(4,4,7)
        };
        
        var items = _items
            .GroupBy(x=>x.ParentId)
            .Select(x=>new
                    {
                        ParentId = x.Key,
                        KN = x.Where(_=>_.ItemTypeId == 3).Any() && x.Where(_=>_.ItemTypeId==3).All(_=>_.AttachedFileId!=null),
                        KD = x.Where(_=>_.ItemTypeId == 4).Any() && x.Where(_=>_.ItemTypeId==4).All(_=>_.AttachedFileId!=null),
                        NC = x.Where(_=>_.ItemTypeId == 6).Any() && x.Where(_=>_.ItemTypeId==6).All(_=>_.AttachedFileId!=null),
                    })
            .ToList();
        
        foreach(var i in items)
            Console.WriteLine($"Parent: {i.ParentId}\r\n\tHasKN: {i.KN}\tHasKD: {i.KD}\tHasNC: {i.NC}");
    }
}

Roslyn 2.0 Compiler; Environment version: 4.0.30319.42000

<?xml version="1.0" encoding="utf-16"?>
<data xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" someattributea="" someattributeb="" someattributec="" ExtraAttr="" p1:someattributec="namespace attr" xmlns:p1="http://SomeTestNamespace.com" />
<?xml version="1.0" encoding="utf-16"?>
<data xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" someattributea="replacement value for Someattributea" someattributec="" ExtraAttr="" p1:someattributec="namespace attr" xmlns:p1="http://SomeTestNamespace.com" />

Testing a list of Data.
<?xml version="1.0" encoding="utf-16"?>
<DataList xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <DataItem someattributea="" someattributeb="" someattributec="" ExtraAttr="" p1:someattributec="namespace attr" xmlns:p1="http://SomeTestNamespace.com" xmlns="https://Test Namespace" />
  <DataItem someattributea="" someattributeb="" someattributec="" ExtraAttr="" p1:someattributec="namespace attr" xmlns:p1="http://SomeTestNamespace.com" xmlns="https://Test Namespace" />
</DataList>
<?xml version="1.0" encoding="utf-16"?>
<DataList xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <DataItem someattributea="" someattributeb="" someattributec="" ExtraAttr="" p1:someattributec="namespace attr" xmlns:p1="http://SomeTestNamespace.com" xmlns="https://Test Namespace" />
  <DataItem someattributea="" someattributeb="" someattributec="" ExtraAttr="" p1:someattributec="namespace attr" xmlns:p1="http://SomeTestNamespace.com" xmlns="https://Test Namespace" />
</DataList>

Last Run:	6:50:01 pm
Compile:	1.125s
Execute:	0.29s
Memory:	2.40Mb
CPU:	0.547s

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