protected override void OnBindingContextChanged()
{
base.OnBindingContextChanged();
var newNode = BindingContext as DemoTreeNode;
if (newNode == null)
{
if (Node != null)
{
Debug.WriteLine("OnBindingContextChanged: Node.PropertyChanged unsubscribe");
Node.PropertyChanged -= (sender, e) => AdjustSpacer();
}
Spacer.WidthRequest = 0;
return;
}
Node = BindingContext as DemoTreeNode;
if (Node != null)
{
Debug.WriteLine("OnBindingContextChanged: Node.PropertyChanged subscribe");
Node.PropertyChanged += (sender, e) => AdjustSpacer();
}
}
public DemoTreeViewModel()
{
MyTree = new DemoTreeNode {
Title = "Root", Score = 0.5, IsExpanded = true
};
var a = MyTree.Children.Add(new DemoTreeNode {
Title = "Branch A", Score = 0.75, IsExpanded = true
});
return;
a.Children.Add(new DemoTreeNode {
Title = "Leaf A1", Score = 0.85, IsExpanded = true
});
a.Children.Add(new DemoTreeNode {
Title = "Leaf A2", Score = 0.65, IsExpanded = true
});
var b = MyTree.Children.Add(new DemoTreeNode {
Title = "Branch B", Score = 0.25, IsExpanded = true
});
b.Children.Add(new DemoTreeNode {
Title = "Leaf B1", Score = 0.35, IsExpanded = true
});
b.Children.Add(new DemoTreeNode {
Title = "Leaf B2", Score = 0.15, IsExpanded = true
});
// TODO: start optimizing for performance in supporting larger trees
// var c = MyTree.ChildNodes.Add(new DemoTreeNode { Title = "Branch C", Score = 0.25, IsExpanded = true });
// var c1 = c.ChildNodes.Add(new DemoTreeNode { Title = "Leaf C1", Score = 0.35, IsExpanded = true });
// var c2 = c.ChildNodes.Add(new DemoTreeNode { Title = "Branch C2", Score = 0.15, IsExpanded = true });
// c2.ChildNodes.Add(new DemoTreeNode { Title = "Leaf C2a", Score = 0.15, IsExpanded = true });
//
// var d = MyTree.ChildNodes.Add(new DemoTreeNode { Title = "Branch D", Score = 0.25, IsExpanded = true });
// d.ChildNodes.Add(new DemoTreeNode { Title = "Leaf D1", Score = 0.35, IsExpanded = true });
// d.ChildNodes.Add(new DemoTreeNode { Title = "Leaf D2", Score = 0.15, IsExpanded = true });
}