Question

I am trying to display all possible values for a sub-property. Below I am trying to get all possible colors for all products into a single variable. How can I get allDistinctColors below?

IEnumerable<Product> products = GetAllProducts();
IEnumerable allDistinctColors = ???

public class Product
{
  public List<Option> Options { get; set; }
}

public class Option
{
  public string Color { get; set; }
}

Answer 1

Use SelectMany to select multiple output items (options) per input item (product) and concatenate them into a single enumeration for further querying:

var allDistinctColors = products
    .SelectMany(p => p.Options)
    .Select(o => o.Color)
    .Distinct();