Use AvaloniaList instead of List

samples/ControlCatalog/Pages/SliderPage.xaml

@@ -19,6 +19,7 @@
                 Maximum="100"
                 TickPlacement="BottomRight"
                 IsSnapToTickEnabled="True"
+                Ticks="0,20,25,40,75,100"
                 Width="300" />
       </StackPanel>
       <Slider Value="0"

samples/ControlCatalog/Pages/SliderPage.xaml.cs

@@ -1,4 +1,3 @@
-using System.Collections.Generic;
 using Avalonia.Controls;
 using Avalonia.Markup.Xaml;
 
@@ -14,16 +13,6 @@ namespace ControlCatalog.Pages
         private void InitializeComponent()
         {
             AvaloniaXamlLoader.Load(this);
-
-            var slider = this.FindControl<Slider>("CustomTickedSlider");
-            slider.Ticks = new List<double>
-            {
-                0d,
-                5d,
-                20d,
-                50d,
-                100d
-            };
         }
     }
 }

src/Avalonia.Controls/Slider.cs

@@ -1,5 +1,5 @@
 using System;
-using System.Collections.Generic;
+using Avalonia.Collections;
 using Avalonia.Controls.Mixins;
 using Avalonia.Controls.Primitives;
 using Avalonia.Input;
@@ -68,7 +68,7 @@ namespace Avalonia.Controls
         /// <summary>
         /// Defines the <see cref="TicksProperty"/> property.
         /// </summary>
-        public static readonly StyledProperty<List<double>> TicksProperty =
+        public static readonly StyledProperty<AvaloniaList<double>> TicksProperty =
             TickBar.TicksProperty.AddOwner<Slider>();
 
         // Slider required parts
@@ -105,7 +105,7 @@ namespace Avalonia.Controls
         /// <summary>
         /// Defines the ticks to be drawn on the tick bar.
         /// </summary>
-        public List<double> Ticks
+        public AvaloniaList<double> Ticks
         {
             get => GetValue(TicksProperty);
             set => SetValue(TicksProperty, value);
@@ -263,7 +263,7 @@ namespace Avalonia.Controls
                 double next = Maximum;
 
                 // This property is rarely set so let's try to avoid the GetValue
-                List<double> ticks = Ticks;
+                var ticks = Ticks;
 
                 // If ticks collection is available, use it.
                 // Note that ticks may be unsorted.

src/Avalonia.Controls/TickBar.cs

@@ -1,8 +1,4 @@
-using System;
-using System.Collections.Generic;
-using Avalonia.Controls.Primitives;
-using Avalonia.Data;
-using Avalonia.Data.Converters;
+using Avalonia.Collections;
 using Avalonia.Layout;
 using Avalonia.Media;
 using Avalonia.Utilities;
@@ -135,15 +131,15 @@ namespace Avalonia.Controls
         /// <summary>
         /// Defines the <see cref="Ticks"/> property.
         /// </summary>
-        public static readonly StyledProperty<List<double>> TicksProperty =
-            AvaloniaProperty.Register<TickBar, List<double>>(nameof(Ticks));
+        public static readonly StyledProperty<AvaloniaList<double>> TicksProperty =
+            AvaloniaProperty.Register<TickBar, AvaloniaList<double>>(nameof(Ticks));
 
         /// <summary>
         /// The Ticks property contains collection of value of type Double which
         /// are the logical positions use to draw the ticks.
         /// The property value is a <see cref="DoubleCollection" />.
         /// </summary>
-        public List<double> Ticks
+        public AvaloniaList<double> Ticks
         {
             get { return GetValue(TicksProperty); }
             set { SetValue(TicksProperty, value); }