How to check if all items belong to same type using LINQ

public class  Product
public string Name {set; get;}
public string Type {set; get;}

public class ProductType
public string Name{get;set}

var products = GetProducts();
var productTypes = GetProductTypes(); 

bool isValid = products.All(x=>x.Type == ??) // Help required

I want to make sure that all products in the 'products' belong to only of the product type.

How could achieve this in linq. Any help is much appreciated I am struck with LINQ stuff ? Thanks.


You can check if all items have the same type as the first item:

bool isValid = products.All(x => x.Type == products.First().Type);

You could use Distinct and Count:

isValid = products.Select(x => x.Type).Distinct().Count() == 1;

var isValid = products.Select(p => p.Type).Distinct().Count() == 1;


var first = products.FirstOrDefault();
var isValid == (first == null) ? true : products.All(p => p.Type == first.Type);

If you only want to check the type of each element in LINQ then -

class A{

class B{

static void Main(string[] args)
       ArrayList arr = new ArrayList();
       arr.Add(new A());
       arr.Add(new A());
       arr.Add(new A());
       arr.Add(new B());
       arr.Add(new A());
       int count= arr.ToArray().Count(x=> !x.GetType().Equals(typeof(A)));

Above example, checks the type of each element in array then gets the count of element from array which are not of class type A.

I hope you have same scenario and hope this helps !!

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