public static ObservableDataTreeNode CreateParentNode(object nodeValue, Func<object, Task<List<object>>> query)
{
var newNode = new ObservableDataTreeNode(nodeValue, DataTreeNodeState.ValidData);
newNode.HasChildren = true;
newNode.queryChildren = query;
return newNode;
}
private async void StartQueryChildren(ObservableDataTreeNode node) // TODO: NoWait();
{
if (node.State.HasFlag(DataTreeNodeState.ValidChildren))
{
return;
}
if (queryChildren == null)
{
node.State = DataTreeNodeState.Error;
return;
}
try
{
StatusVisibility = Visibility.Visible;
Task<List<object>> queryChildrenTask = queryChildren(node.Content);
var children = await queryChildrenTask;
RemoveAllChildren();
foreach (var child in children)
{
node.AddChild(ObservableDataTreeNode.CreateParentNode(child, queryChildren));
}
node.State |= DataTreeNodeState.ValidChildren;
StatusVisibility = Visibility.Collapsed;
}
catch
{
node.State = DataTreeNodeState.Error;
}
}