Dynamic definition of `GetEnumerator` using DLR without implementing `GetEnumerator` at compile time. Inspired by http://hotcode.org/speeches/c-deep-dive/

DynamicGetEnumeratorUsingDLR.cs

void Main()
{
    dynamic something = new DynamicEnumerable();
    
    something.DynamicMethod = new Action<string>(str => str.Dump());
    
    "First `dynamic` GetEnumerator".Dump();
    something.GetEnumerator = new Func<IEnumerator>(() => 
                "test of dynamic enumerator".ToCharArray().GetEnumerator());
    
    foreach(dynamic part in something)
    {
        (part as object).Dump();
    }
    
    "Second `dynamic` GetEnumerator".Dump();
    something.GetEnumerator = new Func<IEnumerator>(() => 
                Enumerable.Range(1, 10).GetEnumerator());
    
    foreach(dynamic part in something)
    {
        (part as object).Dump();
    }
    
    something.DynamicMethod("dynamic invication");
}

class DynamicEnumerable : DynamicObject
{
    private readonly Dictionary<string, object> dictionary = new Dictionary<string, object>();

    public override bool TryGetMember(GetMemberBinder binder, out object result)
    {
        return dictionary.TryGetValue(binder.Name, out result);
    }

    public override bool TrySetMember(SetMemberBinder binder, object value)
    {
        dictionary[binder.Name] = value;
        return true;
    }

    public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result)
    {
        Type dictType = typeof(Dictionary<string, object>);
        try
        {
            result = dictType.InvokeMember(
                         binder.Name,
                         BindingFlags.InvokeMethod,
                         null, dictionary, args);
            return true;
        }
        catch       
        {
            result = null;
            return false;
        }
    }
    
    public override bool TryConvert(ConvertBinder binder, out object result)
    {
        if(typeof(IEnumerable).IsAssignableFrom(binder.Type))
        {
            try
            {
                if(dictionary.ContainsKey("GetEnumerator"))
                {
                    
                    result = ((IEnumerator)((Func<object>)dictionary["GetEnumerator"])()).ToIEnumerable();
                }
                else
                {
                    result = Enumerable.Empty<object>();
                }
                
                return true;
            }
            catch(Exception ex)
            {
                ex.Dump();
            }
        }
        
        result = null;
        return false;
    }
}

public static class Extension
{
    public static IEnumerable ToIEnumerable(this IEnumerator enumerator)
    {
        while ( enumerator.MoveNext() ) {
            yield return enumerator.Current;
        }
    }
}

More simple sample by InnerSelf