Question

so i wrote a simple timer class

public class ConsoleTimer : IDisposable
{
    private Stopwatch _watch;
    private IList _items;
    public object Count = "0";

    public ConsoleTimer(IList items) {
        _watch = new Stopwatch();
        _items = items;
        _watch.Start();
    }


    public void Dispose() {
        var c = Console.ForegroundColor;
        Console.ForegroundColor = ConsoleColor.Green;
        _watch.Stop();
        TimeSpan ts = _watch.Elapsed;
        Console.WriteLine(String.Format("{0} items in {1}m {2}s", _items != null ? _items.Count : Count, ts.Minutes, ts.Seconds));
        Console.ForegroundColor = c;
    }
}

as you can see, i accept optional constructor parameter (IList) so that when that list changes during the course of my timer scope, i can automatically write out how many items (rows/records/entities etc) were added.

using it as follows:

        using (ConsoleTimer t = new ConsoleTimer(_values)) {
            _values = GetValues(filter);
        }

Even though _values has a 955 items, the Dispose method of my timer still sees _items as the value that was passed in the constructor (whether it be 0 or null)

is the _items = items assignment not a reference assignment?

Answer 1

But you’re assigning a new reference to _values which won’t be seen by _items! Better to say

foreach(var value in GetValues(filter)) {
    _values.Add(value);
}

Now you’re modifying the original referent so that both _values and _items see the changes.