C#

- Read all lines as strings
- look for leading "//", "/", "", "*/", etc.
- LastIndex of "//" for trailing comments.
- Write clean / accepted lines.

private Dictionary<int, int> d1 = new Dictionary<int, int> {{1, 10}, {2, 20}, {3, 40}};

private Dictionary<int, int> d2 = new Dictionary<int, int> {{1, 12}, {2, 20}, {5, 40}, {6, 50}};

private Dictionary<T1,T2> GetDictDiff<T1, T2>(Dictionary<T1, T2> d1, Dictionary<T1, T2> d2)
{
    Dictionary<T1,T2> kvpDifferences = new Dictionary<T1, T2>();
    
    foreach (KeyValuePair<T1, T2> kvp in d1)
    {
        if (! d2.Keys.Contains(kvp.Key))
        {
            // d1 key not in d2
            kvpDifferences.Add(kvp.Key, d1[kvp.Key]);
        }
        else
        {
            // d1 key in d2
            if (! Equals(d2[kvp.Key], d1[kvp.Key]))
            {
                // different values
                kvpDifferences.Add(kvp.Key, d1[kvp.Key]);
            }
        }
    }

    foreach (KeyValuePair<T1, T2> kvp in d2)
    {
        if (! d1.Keys.Contains(kvp.Key))
        {
            // d2 key not in d1
            kvpDifferences.Add(kvp.Key, d2[kvp.Key]);
        }
    }

    return kvpDifferences;
}

// usage in some method: var test = GetDictDiff<int,int>(d1, d2);

var dictionary1 = new Dictionary<int, Dictionary<int, int>>
{
    [1] = new Dictionary<int, int>
    {
        [1] = 10,
        [2] = 20,
        [3] = 40,
    },
    [2] = new Dictionary<int, int>
    {
        [1] = 15,
        [2] = 28,
        [3] = 40,
    },
    [3] = new Dictionary<int, int>
    {
        [1] = 15,
        [2] = 28,
        [3] = 40,
    },
};

var dictionary2 = new Dictionary<int, Dictionary<int, int>>
{
    [1] = new Dictionary<int, int>
    {
        [1] = 12,
        [2] = 20,
        [3] = 40,
    },
    [2] = new Dictionary<int, int>
    {
        [1] = 15,
        [2] = 25,
        [3] = 40,
    },
    [3] = new Dictionary<int, int>
    {
        [1] = 15,
        [2] = 28,
        [3] = 40,
    },
};

var result = new Dictionary<int, Dictionary<int, int>>();
foreach (var pair in dictionary2)
{
    if (!dictionary1.TryGetValue(pair.Key, out var value))
    {
        result.Add(pair.Key, pair.Value);
    }
    else
    {
        var differences = new Dictionary<int, int>();
        foreach (var item in pair.Value)
        {
            if (!value.TryGetValue(item.Key, out var i) || item.Value != i)
            {
                differences.Add(item.Key, item.Value);
            }
        }
        if (differences.Count != 0)
        {
            result.Add(pair.Key, differences);
        }
    }
}

private static readonly Regex ItemPattern = new Regex(@"^\s*{\s*(?<key>[^,]+)\s*,\s*(?<value>[^;]+)(\s*;\s*(?<key>[^,]+)\s*,\s*(?<value>[^;]+))*\s*}\s*$", RegexOptions.ExplicitCapture);

private static Dictionary<string, string> ParseItem(string value)
{
    var match = ItemPattern.Match(value);
    if (!match.Success) throw new ArgumentException($"Item '{value}' is not in the correct format.", nameof(value));

    var keys = match.Groups["key"].Captures.Cast<Capture>();
    var values = match.Groups["value"].Captures.Cast<Capture>();
    return keys.Zip(values, (k, v) => (key: k.Value, value: v.Value)).ToDictionary(p => p.key, p => p.value);
}

private static string FormatItem(Dictionary<string, string> value)
{
    if (value.Count == 0) return null;
    return "{" + string.Join("; ", value.Select(p => $"{p.Key}, {p.Value}")) + "}";
}

private static string FindChanges(string source, string target)
{
    var sourceItem = ParseItem(source);
    var targetItem = ParseItem(target);
    var result = new Dictionary<string, string>();
    foreach (var pair in targetItem)
    {
        if (!sourceItem.TryGetValue(pair.Key, out var value) || pair.Value != value)
        {
            result.Add(pair.Key, pair.Value);
        }
    }
    
    return FormatItem(result);
}

var dictionary1 = new Dictionary<int, string>
{
    [1] = "{item 1, 10; item 2, 20; item 3, 40}",
    [2] = "{item 1, 15; item 2, 28; item 3, 40}",
    [3] = "{item 1, 15; item 2, 28; item 3, 40}",
};

var dictionary2 = new Dictionary<int, string>
{
    [1] = "{item 1, 12; item 2, 20; item 3, 40}",
    [2] = "{item 1, 15; item 2, 25; item 3, 40}",
    [3] = "{item 1, 15; item 2, 28; item 3, 40}",
};

var result = new Dictionary<int, string>();
foreach (var pair in dictionary2)
{
    if (!dictionary1.TryGetValue(pair.Key, out var value))
    {
        result.Add(pair.Key, pair.Value);
    }
    else if (value != pair.Value)
    {
        result.Add(pair.Key, FindChanges(value, pair.Value));
    }
}

[1] = "{item 1, 12}"
[2] = "{item 2, 25}"

OriginalGriff wrote:

You can install both versions on the same machine

You cannot install the 64-bit version of Microsoft Access Database Engine 2010 because you currently have 32-bit Office producs installed.