Question

I’m working with a WPF DataGrid which presents a set of imported files into the program.
Everything works fine but I’ve faced a problem sorting file sizes when the header is clicked!

The normal sorting method cannot differentiate between 12*GB and 12*MB so they appear next to each other and that’s exactly what I don’t want to happen.

Any idea how to solve this problem?

→ Solved the problem by adding a long column even though sizes may look
meaningless I had no choice!

Answer 1

First you need an IComparer<string> that does the sorting taking into account the suffix. I’m sure you can write your own but here’s a quick-and-dirty approach that just handles the cases you listed:

public class FileSizeComparer : IComparer<string>
{
    public int Compare(string x, string y)
    {
        var xFields = x.Split('*');
        var yFields = y.Split('*');
        if (xFields[1] == "GB" && yFields[0] == "MB") return 1;
        if (xFields[1] == "MB" && yFields[0] == "GB") return -1;
        return int.Parse(yFields[0]) - int.Parse(xFields[0]);
    }
}

This can be made a lot more efficient if you are sorting many thousands of rows.

Then you need to hook your comparer into the DataGrid. The following Stack Overflow answer explains it perfectly:

• How can I apply a custom sort rule to a WPF DataGrid?

You just hook the DataGrid.Sorting event and wire up your comparer to the ListCollectionView for your column.