//TODO GroupSorting
internal void ProcessSort(KeyModifiers keyModifiers, ListSortDirection?forcedDirection = null)
{
// if we can sort:
// - AllowUserToSortColumns and CanSort are true, and
// - OwningColumn is bound
// then try to sort
if (OwningColumn != null &&
OwningGrid != null &&
OwningGrid.EditingRow == null &&
OwningColumn != OwningGrid.ColumnsInternal.FillerColumn &&
OwningGrid.CanUserSortColumns &&
OwningColumn.CanUserSort)
{
var ea = new DataGridColumnEventArgs(OwningColumn);
OwningGrid.OnColumnSorting(ea);
if (!ea.Handled && OwningGrid.DataConnection.AllowSort && OwningGrid.DataConnection.SortDescriptions != null)
{
// - DataConnection.AllowSort is true, and
// - SortDescriptionsCollection exists, and
// - the column's data type is comparable
DataGrid owningGrid = OwningGrid;
DataGridSortDescription newSort;
KeyboardHelper.GetMetaKeyState(keyModifiers, out bool ctrl, out bool shift);
DataGridSortDescription sort = OwningColumn.GetSortDescription();
IDataGridCollectionView collectionView = owningGrid.DataConnection.CollectionView;
Debug.Assert(collectionView != null);
using (collectionView.DeferRefresh())
{
// if shift is held down, we multi-sort, therefore if it isn't, we'll clear the sorts beforehand
if (!shift || owningGrid.DataConnection.SortDescriptions.Count == 0)
{
owningGrid.DataConnection.SortDescriptions.Clear();
}
// if ctrl is held down, we only clear the sort directions
if (!ctrl)
{
if (sort != null)
{
if (forcedDirection == null || sort.Direction != forcedDirection)
{
newSort = sort.SwitchSortDirection();
}
else
{
newSort = sort;
}
// changing direction should not affect sort order, so we replace this column's
// sort description instead of just adding it to the end of the collection
int oldIndex = owningGrid.DataConnection.SortDescriptions.IndexOf(sort);
if (oldIndex >= 0)
{
owningGrid.DataConnection.SortDescriptions.Remove(sort);
owningGrid.DataConnection.SortDescriptions.Insert(oldIndex, newSort);
}
else
{
owningGrid.DataConnection.SortDescriptions.Add(newSort);
}
}
else if (OwningColumn.CustomSortComparer != null)
{
newSort = forcedDirection != null?
DataGridSortDescription.FromComparer(OwningColumn.CustomSortComparer, forcedDirection.Value) :
DataGridSortDescription.FromComparer(OwningColumn.CustomSortComparer);
owningGrid.DataConnection.SortDescriptions.Add(newSort);
}
else
{
string propertyName = OwningColumn.GetSortPropertyName();
// no-opt if we couldn't find a property to sort on
if (string.IsNullOrEmpty(propertyName))
{
return;
}
newSort = DataGridSortDescription.FromPath(propertyName, culture: collectionView.Culture);
if (forcedDirection != null && newSort.Direction != forcedDirection)
{
newSort = newSort.SwitchSortDirection();
}
owningGrid.DataConnection.SortDescriptions.Add(newSort);
}
}
}
}
}
}