C# how to pass a string from a list of object to a List<T>.Sort() method please?

Question

How to pass a string (level) from a list of object to a List<T>.Sort() method please?

Data:
        List<DirItem> items = new List<DirItem>
        {
           new DirItem { level="3.5-1", name="Hi", description="Hello" },
           new DirItem { level="3.5", name="Hi", description="Hello" },
           new DirItem { level="4.1.1-1", name="Hi", description="Hello" }
        };


Use this to sort strings like 1.1.-1
items.Sort((x, y) =>       // How do I do this bit? Passing 'level' as the string to Sort please?
{
    var xparts = x.Split('.');
    var yparts = y.Split('.');
    for (int i = 0; i < xparts.Length; i++)
    {
        if (i >= yparts.Length)
            return 1;
        var xval = int.Parse(xparts[i]);
        var yval = int.Parse(yparts[i]);
        if (xval != yval)
            return xval.CompareTo(yval);
    }
    return xparts.Length.CompareTo(yparts.Length);
});

Answer 1

split by ".", then by "-" then compare

	    items.Sort((a,b) => 
        {
			Func<int[], int[], int> CompareArrays = (a1, a2) => 
			{
				for (var i = 0; i < a1.Length; ++i)
				{
					if (i >= a2.Length || a1[i] > a2[i])
						return 1;
					if (a1[i] < a2[i])
						return -1;
				}
				return a2.Length > a1.Length ? -1 : 0;
			};
			Func<string, int[]> LevelToArray = (s) => s.Split('.')
				.SelectMany(e => e.Split('-'))
				.Select(e => int.Parse(e)).ToArray();
			return CompareArrays(LevelToArray(a.level), LevelToArray(b.level));
		});