JavaScript spread syntax in C#

Question

Is there any implementation in C# like JavaScript\'s spread syntax?

var arr = new []{
   \"1\",
   \"2\"//...
};

Console.WriteLine(...arr);

Answer 1

One trick to get a behavior similar to this (without reflection) is to accept params SomeObject[][] and to also define an implicit operator from SomeObject to SomeObject[]. Now you can pass a mixture of arrays of SomeObject and individual SomeObject elements.

public class Item
{
    public string Text { get; }

    public Item (string text)
    {
        this.Text = text;
    }

    public static implicit operator Item[] (Item one) => new[] { one };
}

public class Print
{
    // Accept a params of arrays of items (but also single items because of implicit cast)

    public static void WriteLine(params Item[][] items)
    {
        Console.WriteLine(string.Join(", ", items.SelectMany(x => x)));
    }
}

public class Test
{
    public void Main()
    {
        var array = new[] { new Item("a1"), new Item("a2"), new Item("a3") };
        Print.WriteLine(new Item("one"), /* ... */ array, new Item("two")); 
    }
}