foreach with index [duplicate]

Answer 1

I just figured out interesting solution:

public class DepthAware : IEnumerable
{
    private readonly IEnumerable source;

    public DepthAware(IEnumerable source)
    {
        this.source = source;
        this.Depth = 0;
    }

    public int Depth { get; private set; }

    private IEnumerable GetItems()
    {
        foreach (var item in source)
        {
            yield return item;
            ++this.Depth;
        }
    }

    public IEnumerator GetEnumerator()
    {
        return GetItems().GetEnumerator();
    }

    IEnumerator IEnumerable.GetEnumerator()
    {
        return GetEnumerator();
    }
}

// Generic type leverage and extension invoking
public static class DepthAware
{
    public static DepthAware AsDepthAware(this IEnumerable source)
    {
        return new DepthAware(source);
    }

    public static DepthAware New(IEnumerable source)
    {
        return new DepthAware(source);
    }
}

Usage:

var chars = new[] {'a', 'b', 'c', 'd', 'e', 'f', 'g'}.AsDepthAware();

foreach (var item in chars)
{
    Console.WriteLine("Char: {0}, depth: {1}", item, chars.Depth);
}