Sorting

Users can sort by clicking a column header when both of these allow it:

TreeDataGrid.CanUserSortColumns
the column's own CanUserSortColumn

Disable Sorting in XAML

<TreeDataGridTextColumn Header="Name"
                        Binding="{Binding Name}"
                        CanUserSortColumn="False"/>

Custom Comparisons

The fluent API uses Comparison<object?> delegates for custom sorting:

source.WithTextColumn("Name", x => x.Name, o =>
{
    o.CompareAscending = (a, b) =>
        string.Compare(((Person?)a)?.Name, ((Person?)b)?.Name, StringComparison.CurrentCulture);
});

Clear Sorting

Both source types expose ClearSort:

Source.ClearSort();