Linq join objects child/parent | C# Online Compiler

Linq join objects child/parent by Kritner

using System;
using System.Collections.Generic;
using System.Linq;

public class Foo
{
    public int UserId { get; set; }
    public List<Bar> Bars { get; set; }
}

public class Bar
{
    public string SomeProperty { get; set; }
    public string SomePropertyINeedToUpdate { get; set; }
}

public class Program
{
	public static void Main()
	{
		var stuff = 
			from p in Program.OldData()
			select new 
		    {
			   UserId = p.UserId
		    };
		
		foreach (var item in stuff)
		{
			Console.WriteLine(item.UserId);
		}
		
		var otherStuff = 
			from p in Program.OldData().SelectMany(sm => sm.Bars)
			select new 
		    {
			   SomeProperty = p.SomeProperty
		    };
		
		foreach (var item in otherStuff)
		{
			Console.WriteLine(item.SomeProperty);
		}
		
		// Take OldData and join it to NewData on Foo.UserId and Foo.Bars.SomeProperty
		// Take the result of the successful join and update OldData's 
	}
	
	public static List<Foo> OldData()
	{
		return new List<Foo>()
		{
			new Foo()
			{
				UserId = 1,
				Bars = new List<Bar>()
				{
					new Bar()
					{
						SomeProperty = "Test",
						SomePropertyINeedToUpdate = "Going To Update"
					},
					new Bar()
					{
						SomeProperty = "Other Test",
						SomePropertyINeedToUpdate = "No need to update"
					}
				}
			},
			new Foo()
			{
				UserId = 2,
				Bars = new List<Bar>()
				{
					new Bar()
					{
						SomeProperty = "blah Test",
						SomePropertyINeedToUpdate = "Going To Update"
					},
					new Bar()
					{
						SomeProperty = "blah Other Test",
						SomePropertyINeedToUpdate = "No need to update"
					}
				}				
			}
		};
	}
	
public static List<Foo> NewData()
	{
		return new List<Foo>()
		{
			new Foo()
			{
				UserId = 1,
				Bars = new List<Bar>()
				{
					new Bar()
					{
						SomeProperty = "Test",
						SomePropertyINeedToUpdate = "Blah Updated"
					},
					new Bar()
					{
						SomeProperty = "jaosidfj Test",
						SomePropertyINeedToUpdate = "No need to update"
					}
				}
			},
			new Foo()
			{
				UserId = 2,
				Bars = new List<Bar>()
				{
					new Bar()
					{
						SomeProperty = "Test",
						SomePropertyINeedToUpdate = "Updated"
					},
					new Bar()
					{
						SomeProperty = "asodifj",
						SomePropertyINeedToUpdate = "No need to update"
					}
				}				
			}
		};
	}	
}

​x
 
using System;
using System.Collections.Generic;
using System.Linq;
​
public class Foo
{
    public int UserId { get; set; }
    public List<Bar> Bars { get; set; }
}
​
public class Bar
{
    public string SomeProperty { get; set; }
    public string SomePropertyINeedToUpdate { get; set; }
}
​
public class Program
{
    public static void Main()
    {
        var stuff = 
            from p in Program.OldData()
            select new 
            {
               UserId = p.UserId
            };
        
        foreach (var item in stuff)
        {
            Console.WriteLine(item.UserId);
        }
        
        var otherStuff = 
            from p in Program.OldData().SelectMany(sm => sm.Bars)
            select new 
            {
               SomeProperty = p.SomeProperty
            };
        
        foreach (var item in otherStuff)
        {
            Console.WriteLine(item.SomeProperty);
        }
        
        // Take OldData and join it to NewData on Foo.UserId and Foo.Bars.SomeProperty
        // Take the result of the successful join and update OldData's 
    }
    
    public static List<Foo> OldData()
    {
        return new List<Foo>()
        {
            new Foo()
            {
                UserId = 1,
                Bars = new List<Bar>()
                {
                    new Bar()
                    {
                        SomeProperty = "Test",
                        SomePropertyINeedToUpdate = "Going To Update"
                    },
                    new Bar()
                    {
                        SomeProperty = "Other Test",
                        SomePropertyINeedToUpdate = "No need to update"
                    }
                }
            },
            new Foo()
            {
                UserId = 2,
                Bars = new List<Bar>()
                {
                    new Bar()
                    {
                        SomeProperty = "blah Test",
                        SomePropertyINeedToUpdate = "Going To Update"
                    },
                    new Bar()
                    {
                        SomeProperty = "blah Other Test",
                        SomePropertyINeedToUpdate = "No need to update"
                    }
                }               
            }
        };
    }
    
public static List<Foo> NewData()
    {
        return new List<Foo>()
        {
            new Foo()
            {
                UserId = 1,
                Bars = new List<Bar>()
                {
                    new Bar()
                    {
                        SomeProperty = "Test",
                        SomePropertyINeedToUpdate = "Blah Updated"
                    },
                    new Bar()
                    {
                        SomeProperty = "jaosidfj Test",
                        SomePropertyINeedToUpdate = "No need to update"
                    }
                }
            },
            new Foo()
            {
                UserId = 2,
                Bars = new List<Bar>()
                {
                    new Bar()
                    {
                        SomeProperty = "Test",
                        SomePropertyINeedToUpdate = "Updated"
                    },
                    new Bar()
                    {
                        SomeProperty = "asodifj",
                        SomePropertyINeedToUpdate = "No need to update"
                    }
                }               
            }
        };
    }   
}
​
​

1
2
Test
Other Test
blah Test
blah Other Test

Cached Result
Last Run:	3:20:18 am
Compile:	0.157s
Execute:	0s
Memory:	0b
CPU:	0s

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