/// <summary>
/// Creates a collection view around the DataGrid's source. ICollectionViewFactory is
/// used if the source implements it. Otherwise a PagedCollectionView is returned.
/// </summary>
/// <param name="source">Enumerable source for which to create a view</param>
/// <returns>ICollectionView view over the provided source</returns>
internal static IDataGridCollectionView CreateView(IEnumerable source)
{
Debug.Assert(source != null, "source unexpectedly null");
Debug.Assert(!(source is IDataGridCollectionView), "source is an ICollectionView");
IDataGridCollectionView collectionView = null;
if (source is IDataGridCollectionViewFactory collectionViewFactory)
{
// If the source is a collection view factory, give it a chance to produce a custom collection view.
collectionView = collectionViewFactory.CreateView();
// Intentionally not catching potential exception thrown by ICollectionViewFactory.CreateView().
}
if (collectionView == null)
{
// If we still do not have a collection view, default to a PagedCollectionView.
collectionView = new DataGridCollectionView(source);
}
return(collectionView);
}
//TODO GroupSorting
internal void ProcessSort(KeyModifiers keyModifiers)
{
// if we can sort:
// - DataConnection.AllowSort is true, and
// - AllowUserToSortColumns and CanSort are true, and
// - OwningColumn is bound, and
// - SortDescriptionsCollection exists, and
// - the column's data type is comparable
// then try to sort
if (OwningColumn != null &&
OwningGrid != null &&
OwningGrid.EditingRow == null &&
OwningColumn != OwningGrid.ColumnsInternal.FillerColumn &&
OwningGrid.DataConnection.AllowSort &&
OwningGrid.CanUserSortColumns &&
OwningColumn.CanUserSort &&
OwningGrid.DataConnection.SortDescriptions != null)
{
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)
{
newSort = sort.SwitchSortDirection();
// 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
{
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);
owningGrid.DataConnection.SortDescriptions.Add(newSort);
}
}
}
}
}
