Question

I have a method that I am currently building to compare two lists of objects. The lists themselves contain objects

List<TradeFile> list1
List<TradeFile> list2

When I finish comparing TradeFile object from list1 and TradeFile object from list2, I want to return a collection that contains all of the compared TradeFiles and the matching status. So it would be something like:

TradeFile1, TradeFile2, True
TradeFile1, TradeFile2, False

I will use this collection then for reporting later in my process. Should I look at using something like a dictionary that contains a collection of the tradefile objects?

This may work, but really feels messy:

Dictonary<Dictonary<TradeFile,TradeFile>,bool>

Edit:
This is what it ended up looking like based on some the answer below.

private List CompareTradeFileObject(List list1, List list2)
{
List results = new List();
bool matches = false;

        if (list1.Count == list2.Count)
        {
            list1.Sort((x, y) => x.FormatName.CompareTo(y.FormatName));
            list2.Sort((x, y) => x.FormatName.CompareTo(y.FormatName));

            for (int i = 0; i < list1.Count; i++)
            {
                TradeFileCompare tf = new TradeFileCompare();
                tf.TradeFile1 = list1[i];
                tf.TradeFile2 = list2[i];

                if (list1[i].FileExtension == list2[i].FileExtension && list1[i].FormatName == list2[i].FormatName &&
                    list1[i].GroupName == list2[i].GroupName && list1[i].MasterAccountId == list2[i].MasterAccountId)
                {
                    matches = CompareTradeFileContents(list1[i].FileContents, list2[i].FileContents);
                    tf.IsMatch = matches;

                }
                else
                {
                    tf.IsMatch = matches;
                }

                results.Add(tf);
            }
        }
        else
        {
            matches = false;
        }

        return results;
    }

class TradeFileCompare
{
    public TradeFile TradeFile1 { get; set; }
    public TradeFile TradeFile2 { get; set; }
    public bool IsMatch { get; set; }
}

Answer 1

void Main()
{
    var list1 = new List<TradeFile>(new [] {
        new TradeFile { Name = "TradeFile1", Data = "a" },
        new TradeFile { Name = "TradeFile2",  Data = "b" },
    });

    var list2 = new List<TradeFile>(new [] {
        new TradeFile { Name = "TradeFile4",  Data = "a" },
        new TradeFile { Name = "TradeFile5",  Data = "c" },
    });

    var query = from tradeFile1 in list1
                from tradeFile2 in list2
                select new TradeFileComparison(tradeFile1, tradeFile2);

    foreach (var item in query)
    {
        Console.WriteLine(item.ToString());
    }
}

class TradeFile
{
    public string Name { get; set; }

    public string Data { get; set; }

    public bool Matches(TradeFile otherTradeFile)
    {
        return (this.Data == otherTradeFile.Data);
    }
}

class TradeFileComparison
{
    public TradeFileComparison(TradeFile tradeFile1, TradeFile tradeFile2)
    {
        this.TradeFile1 = tradeFile1;
        this.TradeFile2 = tradeFile2;
    }

    public TradeFile TradeFile1 { get; set; }

    public TradeFile TradeFile2 { get; set; }

    bool IsMatch { get { return this.TradeFile1.Matches(TradeFile2); } }

    public override string ToString()
    {
        return string.Format("{0}, {1}, {2}", 
            this.TradeFile1.Name, this.TradeFile2.Name, 
            this.IsMatch.ToString());
    }
}

Output:

TradeFile1, TradeFile4, True
TradeFile1, TradeFile5, False
TradeFile2, TradeFile4, False
TradeFile2, TradeFile5, False