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Nitrox.Launcher/Models/Design/MultiDataTemplate.cs

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+extern alias JB;
+using System;
+using System.Collections.Generic;
+using Avalonia.Collections;
+using Avalonia.Controls;
+using Avalonia.Controls.Templates;
+using Avalonia.Markup.Xaml.Templates;
+using Avalonia.Metadata;
+using JB::JetBrains.Annotations;
+
+namespace Nitrox.Launcher.Models.Design;
+
+/// <summary>
+///     Selects a <see cref="DataTemplate" /> based on its <see cref="DataTemplate.DataType" />.
+/// </summary>
+public class MultiDataTemplate : AvaloniaList<DataTemplate>, IRecyclingDataTemplate
+{
+    [Content]
+    [UsedImplicitly]
+    public List<DataTemplate> Content { get; set; } = new();
+
+    private readonly Dictionary<Type, Control> typeToControlCache = [];
+
+    public bool Match(object data) => GetTemplateForType(data?.GetType()) != null;
+
+    public Control Build(object data, Control existing)
+    {
+        Type type = data?.GetType();
+        if (type != null && typeToControlCache.TryGetValue(type, out Control control))
+        {
+            return control;
+        }
+        Control build = GetTemplateForType(type)?.Build(data);
+        if (type != null && build != null)
+        {
+            typeToControlCache[type] = build;
+        }
+
+        return build ?? existing;
+    }
+
+    public Control Build(object data) => GetTemplateForType(data.GetType())?.Build(data) ?? new TextBlock { Text = "" };
+
+    private IDataTemplate GetTemplateForType(Type type)
+    {
+        if (type == null)
+        {
+            return null;
+        }
+        foreach (DataTemplate template in Content)
+        {
+            if (template.DataType?.IsAssignableTo(type) ?? false)
+            {
+                return template;
+            }
+        }
+        return null;
+    }
+}