How to sort a listview by file size?

Question

I have a listview with 4 columns - Name, Extension, Size and Location. I have a method that takes the file size in bytes and converts to KB, MB, GB, etc as needed. An example output would be a 1024 byte file which is printed as "1KB". This value is then placed in the listview.

What I need to do is sort the size column intelligently. Right now the sorting is just a simple comparison so 1025 KB is higher than 1024 MB. How can I make it "size aware"?

My current sorting code is from this KB article: http://support.microsoft.com/kb/319401 And here is my code that generates the file size text:

        public static string getDynamicFileSize(string fileName)
    {
        FileInfo fi = new FileInfo(fileName);
        long sizeInBytes = fi.Length;
        if (sizeInBytes >= 1073741824)
        {
            double sizeInGB = sizeInBytes / Math.Pow(1024, 3);
            return Math.Round(sizeInGB, 2) + " GB";
        }

        if (sizeInBytes >= 1048576)
        {
            double sizeInMB = sizeInBytes / Math.Pow(1024, 2);
            return Math.Round(sizeInMB, 2) + " MB";
        }

        if (sizeInBytes >= 1024)
        {
            double sizeInKB = sizeInBytes / Math.Pow(1024,1);
            return Math.Round(sizeInKB, 2) + " KB";
        }

        //No conversion needed
        return sizeInBytes + " bytes";
    }

Thank you.

Answer 1

Most every object in .NET has a Tag member. This is a place where you can stuff anything extra you need to. In your case, I would stuff the file size in bytes into the ListViewSubItem.Tag property. Then, your sort algorithm can use that to sort by instead of the column text.