/// <summary>
/// Highlights the symbol node corresponding to the current caret position in the editor, expands/collapses nodes, then updates the UI.
/// </summary>
private async ValueTask HighlightExpandAndPresentItemsAsync(ImmutableSegmentedList <ExpansionOption> expansionOption, CancellationToken cancellationToken)
{
var model = await _filterAndSortDataModelQueue.WaitUntilCurrentBatchCompletesAsync().ConfigureAwait(false);
if (model is null)
{
return;
}
// Switch to the UI thread to get the current caret point and latest active text view then create the UI model.
await _threadingContext.JoinableTaskFactory.SwitchToMainThreadAsync(cancellationToken);
var activeTextView = GetLastActiveIWpfTextView();
if (activeTextView is null)
{
return;
}
var caretPoint = activeTextView.GetCaretPoint(activeTextView.TextBuffer);
if (!caretPoint.HasValue)
{
return;
}
var documentSymbolUIItems = DocumentOutlineHelper.GetDocumentSymbolUIItems(model.DocumentSymbolData, _threadingContext);
// Switch to the threadpool to determine which node to select (if applicable).
await TaskScheduler.Default;
var symbolToSelect = DocumentOutlineHelper.GetDocumentNodeToSelect(documentSymbolUIItems, model.OriginalSnapshot, caretPoint.Value);
// Switch to the UI thread to update the view.
await _threadingContext.JoinableTaskFactory.SwitchToMainThreadAsync(cancellationToken);
// Expand/collapse nodes based on the given Expansion Option.
var expansion = expansionOption.Last();
if (expansion is not ExpansionOption.NoChange && SymbolTree.ItemsSource is not null)
{
DocumentOutlineHelper.SetIsExpanded(documentSymbolUIItems, (IEnumerable <DocumentSymbolUIItem>)SymbolTree.ItemsSource, expansion);
}
// Hightlight the selected node if it exists, otherwise unselect all nodes (required so that the view does not select a node by default).
if (symbolToSelect is not null)
{
// Expand all ancestors first to ensure the selected node will be visible.
DocumentOutlineHelper.ExpandAncestors(documentSymbolUIItems, symbolToSelect.RangeSpan);
symbolToSelect.IsSelected = true;
}
else
{
// On Document Outline Control initialization, SymbolTree.ItemsSource is null
if (SymbolTree.ItemsSource is not null)
{
DocumentOutlineHelper.UnselectAll((IEnumerable <DocumentSymbolUIItem>)SymbolTree.ItemsSource);
}
}
SymbolTree.ItemsSource = documentSymbolUIItems;
}