IOrderedEnumerable <TreeViewItem <TreeElementType> > GetInitialOrder(IEnumerable <TreeViewItem <TreeElementType> > types, int[] history)
{
int index = history[0];
TreeViewColumn column = this.columns[index];
bool ascending = multiColumnHeader.IsSortedAscending(index);
// If a sorting function was provided
if (column.selectorFunction != null)
{
return(types.Order(l => column.selectorFunction(l), ascending));
}
// Default
return(types.Order(l => l.item.name, ascending));
}
private void SortByMultipleColumns()
{
int[] sortedColumns = multiColumnHeader.state.sortedColumns;
if (sortedColumns.Empty())
{
return;
}
var types = rootItem.children.Cast <TreeViewItem <TreeElementType> >();
var orderedQuery = GetInitialOrder(types, sortedColumns);
for (int c = 1; c < sortedColumns.Length; ++c)
{
int index = sortedColumns[c];
TreeViewColumn column = this.columns[index];
bool ascending = this.multiColumnHeader.IsSortedAscending(index);
orderedQuery = orderedQuery.ThenBy(l => column.selectorFunction(l), ascending);
}
this.rootItem.children = orderedQuery.Cast <TreeViewItem>().ToList();
}
