From d504c861993bb002635e64fc470ba80509769a05 Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@gmail.com>
Date: Wed, 13 May 2020 13:00:51 +0200
Subject: [PATCH] Added a "Select Random Item" button to TreeView page.

Causes an exception due to containers not being materialized.
---
 samples/ControlCatalog/Pages/TreeViewPage.xaml        |  1 +
 .../ViewModels/TreeViewPageViewModel.cs               | 11 +++++++++++
 2 files changed, 12 insertions(+)

diff --git a/samples/ControlCatalog/Pages/TreeViewPage.xaml b/samples/ControlCatalog/Pages/TreeViewPage.xaml
index 6019d5f91f..789b45e62c 100644
--- a/samples/ControlCatalog/Pages/TreeViewPage.xaml
+++ b/samples/ControlCatalog/Pages/TreeViewPage.xaml
@@ -20,6 +20,7 @@
 
         <Button Command="{Binding AddItemCommand}">Add</Button>
         <Button Command="{Binding RemoveItemCommand}">Remove</Button>
+        <Button Command="{Binding SelectRandomItemCommand}">Select Random</Button>
 
         <ComboBox SelectedIndex="{Binding SelectionMode, Mode=TwoWay}">
           <ComboBoxItem>Single</ComboBoxItem>
diff --git a/samples/ControlCatalog/ViewModels/TreeViewPageViewModel.cs b/samples/ControlCatalog/ViewModels/TreeViewPageViewModel.cs
index d396ef2b3d..5bc23e2fe5 100644
--- a/samples/ControlCatalog/ViewModels/TreeViewPageViewModel.cs
+++ b/samples/ControlCatalog/ViewModels/TreeViewPageViewModel.cs
@@ -23,12 +23,14 @@ namespace ControlCatalog.ViewModels
 
             AddItemCommand = ReactiveCommand.Create(AddItem);
             RemoveItemCommand = ReactiveCommand.Create(RemoveItem);
+            SelectRandomItemCommand = ReactiveCommand.Create(SelectRandomItem);
         }
 
         public ObservableCollection<Node> Items { get; }
         public SelectionModel Selection { get; }
         public ReactiveCommand<Unit, Unit> AddItemCommand { get; }
         public ReactiveCommand<Unit, Unit> RemoveItemCommand { get; }
+        public ReactiveCommand<Unit, Unit> SelectRandomItemCommand { get; }
 
         public SelectionMode SelectionMode
         {
@@ -74,6 +76,15 @@ namespace ControlCatalog.ViewModels
             }
         }
 
+        private void SelectRandomItem()
+        {
+            var random = new Random();
+            var depth = random.Next(4);
+            var indexes = Enumerable.Range(0, 4).Select(x => random.Next(10));
+            var path = new IndexPath(indexes);
+            Selection.SelectedIndex = path;
+        }
+
         private void SelectionChanged(object sender, SelectionModelSelectionChangedEventArgs e)
         {
             var selected = string.Join(",", e.SelectedIndices);