Linq Left outer Join and Group By SO 27792409 | C# Online Compiler

Linq Left outer Join and Group By SO 27792409 by Ehsan Sajjad

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

public class Program
{
	public static void Main()
	{
		List<Category> listCategories = new List<Category>
		{
		new Category
		{
		Id = 1, CateName = "SmartPhone"
		}

		, new Category
		{
		Id = 2, CateName = "Laptop"
		}

		, new Category
		{
		Id = 3, CateName = "Desktop"
		}

		, }

		;
		List<Product> listProducts = new List<Product>
		{
		new Product
		{
		Id = 1, ProdName = "Lumia 720", CategoryId = 1
		}

		, new Product
		{
		Id = 2, ProdName = "PC HP", CategoryId = 3
		}

		, new Product
		{
		Id = 3, ProdName = "PC Dell", CategoryId = 3
		}

		, }

		;
		var query =
			from p in listProducts
			join c in listCategories on p.CategoryId equals c.Id into e
			from j in e.DefaultIfEmpty()group p by new
			{
			j.Id, j.CateName
			}

				into g
				select new GroupModel
				{
				Products = g.ToList(), CategoryId = g.Key.Id, CateogryName = g.Key.CateName
				}

		;
		foreach (var item in query)
		{
			Console.WriteLine("CategoryName: {0}", item.CateogryName);
			foreach(var product in item.Products)
			{
			Console.WriteLine("Product: {0}", product.ProdName);
			}
		}
	}
}

public class Category
{
	public int Id
	{
		get;
		set;
	}

	public string CateName
	{
		get;
		set;
	}
}

public class Product
{
	public int Id
	{
		get;
		set;
	}

	public string ProdName
	{
		get;
		set;
	}

	public int CategoryId
	{
		get;
		set;
	}
}

public class GroupModel
{
	public int CategoryId
	{
		get;
		set;
	}

	public string CateogryName
	{
		get;
		set;
	}

	public List<Product> Products
	{
		get;
		set;
	}
}

​x
 
using System;
using System.Linq;
using System.Collections.Generic;
​
public class Program
{
    public static void Main()
    {
        List<Category> listCategories = new List<Category>
        {
        new Category
        {
        Id = 1, CateName = "SmartPhone"
        }
​
        , new Category
        {
        Id = 2, CateName = "Laptop"
        }
​
        , new Category
        {
        Id = 3, CateName = "Desktop"
        }
​
        , }
​
        ;
        List<Product> listProducts = new List<Product>
        {
        new Product
        {
        Id = 1, ProdName = "Lumia 720", CategoryId = 1
        }
​
        , new Product
        {
        Id = 2, ProdName = "PC HP", CategoryId = 3
        }
​
        , new Product
        {
        Id = 3, ProdName = "PC Dell", CategoryId = 3
        }
​
        , }
​
        ;
        var query =
            from p in listProducts
            join c in listCategories on p.CategoryId equals c.Id into e
            from j in e.DefaultIfEmpty()group p by new
            {
            j.Id, j.CateName
            }
​
                into g
                select new GroupModel
                {
                Products = g.ToList(), CategoryId = g.Key.Id, CateogryName = g.Key.CateName
                }
​
        ;
        foreach (var item in query)
        {
            Console.WriteLine("CategoryName: {0}", item.CateogryName);
            foreach(var product in item.Products)
            {
            Console.WriteLine("Product: {0}", product.ProdName);
            }
        }
    }
}
​
public class Category
{
    public int Id
    {
        get;
        set;
    }
​
    public string CateName
    {
        get;
        set;
    }
}
​
public class Product
{
    public int Id
    {
        get;
        set;
    }
​
    public string ProdName
    {
        get;
        set;
    }
​
    public int CategoryId
    {
        get;
        set;
    }
}
​
public class GroupModel
{
    public int CategoryId
    {
        get;
        set;
    }
​
    public string CateogryName
    {
        get;
        set;
    }
​
    public List<Product> Products
    {
        get;
        set;
    }
}

View IL Code