Add a simple example of using CellValueChanged.

Change the background color of a row with a country name staring with `A`.
AvaloniaUI · Dec 13, 2024 · c927562 · c927562
1 parent ef0561f
commit c927562
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Showing 4 changed files with 46 additions and 14 deletions.
diff --git a/samples/TreeDataGridDemo/MainWindow.axaml b/samples/TreeDataGridDemo/MainWindow.axaml
@@ -28,7 +28,9 @@
         </StackPanel>
         <TreeDataGrid Name="countries"
                       Source="{Binding Countries.Source}"
-                      AutoDragDropRows="True">
+                      AutoDragDropRows="True"
+                      CellValueChanged="TreeDataGrid_CellValueChanged"
+                      RowPrepared="TreeDataGrid_RowPrepared">
           <TreeDataGrid.Resources>
             <!-- Template for Region column cells -->
             <DataTemplate x:Key="RegionCell" DataType="m:Country">

diff --git a/samples/TreeDataGridDemo/MainWindow.axaml.cs b/samples/TreeDataGridDemo/MainWindow.axaml.cs
@@ -6,6 +6,7 @@
 using Avalonia.Interactivity;
 using Avalonia.LogicalTree;
 using Avalonia.Markup.Xaml;
+using Avalonia.Media;
 using Avalonia.Threading;
 using Avalonia.VisualTree;
 using TreeDataGridDemo.Models;
@@ -128,5 +129,30 @@ private void UpdateRealizedCount()
             var unrealizedRowCount = rows.GetVisualChildren().Count() - realizedRowCount;
             textBlock.Text = $"{realizedRowCount} rows realized ({unrealizedRowCount} unrealized)";
         }
+
+        private void TreeDataGrid_RowPrepared(object? sender, TreeDataGridRowEventArgs e)
+        {
+            if (DataContext is not MainWindowViewModel vm)
+                return;
+
+            var modelIndex = vm.Countries.Source.Rows.RowIndexToModelIndex(e.RowIndex);
+            var model = vm.Countries.Data[modelIndex[0]];
+
+            e.Row.Background = model.Name?.StartsWith('A') == true ? Brushes.Yellow : null;
+        }
+
+        private void TreeDataGrid_CellValueChanged(object? sender, TreeDataGridCellEventArgs e)
+        {
+            if (DataContext is not MainWindowViewModel vm ||
+                sender is not TreeDataGrid tdg ||
+                e.ColumnIndex != 0 ||
+                tdg.TryGetRow(e.RowIndex) is not {  } row)
+                return;
+
+            var modelIndex = vm.Countries.Source.Rows.RowIndexToModelIndex(e.RowIndex);
+            var model = vm.Countries.Data[modelIndex[0]];
+
+            row.Background = model.Name?.StartsWith('A') == true ? Brushes.Yellow : null;
+        }
     }
 }
diff --git a/samples/TreeDataGridDemo/Models/Country.cs b/samples/TreeDataGridDemo/Models/Country.cs
@@ -1,8 +1,17 @@
-namespace TreeDataGridDemo.Models
+using ReactiveUI;
+
+namespace TreeDataGridDemo.Models
 {
-    internal class Country
+    internal class Country : ReactiveObject
     {
-        public string? Name { get; set; }
+        private string? _name;
+
+        public string? Name 
+        { 
+            get => _name;
+            set => this.RaiseAndSetIfChanged(ref _name, value);
+        }
+
         public string Region { get; private set; }
         public int Population { get; private set; }
         //Square Miles

diff --git a/samples/TreeDataGridDemo/ViewModels/CountriesPageViewModel.cs b/samples/TreeDataGridDemo/ViewModels/CountriesPageViewModel.cs
@@ -10,14 +10,13 @@ namespace TreeDataGridDemo.ViewModels
 {
     internal class CountriesPageViewModel : ReactiveObject
     {
-        private readonly ObservableCollection<Country> _data;
         private bool _cellSelection;
 
         public CountriesPageViewModel()
         {
-            _data = new ObservableCollection<Country>(Countries.All);
+            Data = new ObservableCollection<Country>(Countries.All);
 
-            Source = new FlatTreeDataGridSource<Country>(_data)
+            Source = new FlatTreeDataGridSource<Country>(Data)
             {
                 Columns =
                 {
@@ -55,18 +54,14 @@ public bool CellSelection
             }
         }
 
+        public ObservableCollection<Country> Data { get; }
         public FlatTreeDataGridSource<Country> Source { get; }
 
-        public void AddCountry(Country country) => _data.Add(country);
+        public void AddCountry(Country country) => Data.Add(country);
 
         public void RemoveSelected()
         {
-            var selection = ((ITreeSelectionModel)Source.Selection!).SelectedIndexes.ToList();
-
-            for (var i = selection.Count - 1; i >= 0; --i)
-            {
-                _data.RemoveAt(selection[i][0]);
-            }
+            Data[0].Name = "Foo";
         }
     }
 }