private static void ApplyColumnSort(DataGridContext dataGridContext, SortDescriptionCollection sortDescriptions, ColumnCollection columns, ColumnBase column, SortDirection sortDirection)
{
if (column == null)
{
throw new ArgumentNullException("column");
}
Debug.Assert((dataGridContext != null) || (column.ParentDetailConfiguration != null));
if ((dataGridContext == null) && (column.ParentDetailConfiguration == null))
{
throw new DataGridInternalException("DataGridContext or ParentDetailConfiguration cannot be null.");
}
if (!columns.Contains(column))
{
throw new ArgumentException("The specified column is not part of the DataGridContext.", "column");
}
string fieldName = column.FieldName;
bool canSort = (dataGridContext != null) ? dataGridContext.Items.CanSort : true;
if ((!string.IsNullOrEmpty(fieldName)) && (canSort == true))
{
SortDescription existingSort;
int sortDescriptionIndex = sortDescriptions.Count;
for (int i = sortDescriptions.Count - 1; i >= 0; i--)
{
existingSort = sortDescriptions[i];
if (existingSort.PropertyName == fieldName)
{
if (((existingSort.Direction == ListSortDirection.Ascending) && (sortDirection == SortDirection.Ascending)) ||
((existingSort.Direction == ListSortDirection.Descending) && (sortDirection == SortDirection.Descending)))
{
// Nothing to change!
sortDescriptionIndex = -1;
}
else
{
sortDescriptionIndex = i;
sortDescriptions.Remove(existingSort);
}
break;
}
}
int maxDescriptions = (dataGridContext != null) ? dataGridContext.MaxSortLevels
: column.ParentDetailConfiguration.MaxSortLevels;
if ((maxDescriptions != -1) && (sortDescriptions.Count >= maxDescriptions))
{
// Cannot insert sort description since it would go beyond the max sort description count.
sortDescriptionIndex = -1;
sortDirection = SortDirection.None;
}
if ((sortDescriptionIndex > -1) && (sortDirection != SortDirection.None))
{
SortDescription sortDescription = new SortDescription(fieldName,
(sortDirection == SortDirection.Ascending) ? ListSortDirection.Ascending : ListSortDirection.Descending);
sortDescriptions.Insert(sortDescriptionIndex, sortDescription);
column.SetSortIndex(sortDescriptionIndex);
column.SetSortDirection(sortDirection);
}
SortingHelper.SynchronizeSortIndexes(sortDescriptions, columns);
}
}