From 1f496184ac73e9266a855835664a0e784a89d566 Mon Sep 17 00:00:00 2001
From: Software Antics <50978201+softwareantics@users.noreply.github.com>
Date: Thu, 17 Aug 2023 18:56:55 +1000
Subject: [PATCH] =?UTF-8?q?=E2=9C=A8=20Change=20`PropertiesView`=20`Title`?=
 =?UTF-8?q?=20to=20"Entity=20Inspector"=20when=20an=20`Entity`=20is=20sele?=
 =?UTF-8?q?cted=20in=20the=20Scene=20Hierarchy=20(#258)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 FinalEngine.Editor.Desktop/App.xaml.cs        |  3 +
 .../Styles/Controls/TextBoxStyle.xaml         |  1 +
 .../Dialogs/Entities/CreateEntityView.xaml    |  4 +-
 .../Dialogs/Layout/SaveWindowLayoutView.xaml  |  2 +-
 .../Views/Docking/DockView.xaml               |  2 +-
 .../Views/Inspectors/EntityInspectorView.xaml |  9 +++
 .../Inspectors/EntityInspectorView.xaml.cs    | 21 ++++++
 .../Views/Inspectors/PropertiesView.xaml      | 10 +++
 .../Views/Scenes/SceneHierarchyView.xaml      |  3 +-
 .../Inspectors/IPropertiesToolViewModel.cs    | 11 +++-
 .../Inspectors/PropertiesToolViewModel.cs     | 64 +++++++++++++++++--
 .../Scenes/ISceneHierarchyToolViewModel.cs    | 10 ++-
 .../Scenes/SceneHierarchyToolViewModel.cs     | 42 +++++++++++-
 .../Inspectors/EntityInspectorViewModel.cs    | 16 +++++
 .../Inspectors/IEntityInspectorViewModel.cs   | 15 +++++
 .../Entities/EntitySelectedMessage.cs         | 36 +++++++++++
 .../PropertiesToolViewModelTests.cs           | 51 ++++++++++++++-
 .../SceneHierarchyToolViewModelTests.cs       | 44 ++++++++++++-
 SharedAssemblyInfo.cs                         |  4 +-
 19 files changed, 327 insertions(+), 21 deletions(-)
 create mode 100644 FinalEngine.Editor.Desktop/Views/Inspectors/EntityInspectorView.xaml
 create mode 100644 FinalEngine.Editor.Desktop/Views/Inspectors/EntityInspectorView.xaml.cs
 create mode 100644 FinalEngine.Editor.ViewModels/Inspectors/EntityInspectorViewModel.cs
 create mode 100644 FinalEngine.Editor.ViewModels/Inspectors/IEntityInspectorViewModel.cs
 create mode 100644 FinalEngine.Editor.ViewModels/Messages/Entities/EntitySelectedMessage.cs

diff --git a/FinalEngine.Editor.Desktop/App.xaml.cs b/FinalEngine.Editor.Desktop/App.xaml.cs
index 61e0f2ad..969747c7 100644
--- a/FinalEngine.Editor.Desktop/App.xaml.cs
+++ b/FinalEngine.Editor.Desktop/App.xaml.cs
@@ -7,6 +7,7 @@ namespace FinalEngine.Editor.Desktop;
 using System.Diagnostics;
 using System.IO.Abstractions;
 using System.Windows;
+using CommunityToolkit.Mvvm.Messaging;
 using FinalEngine.ECS;
 using FinalEngine.Editor.Common.Extensions;
 using FinalEngine.Editor.Common.Models.Scenes;
@@ -108,6 +109,8 @@ private static void ConfigureServices(HostBuilderContext context, IServiceCollec
             builder.AddConsole().SetMinimumLevel(Debugger.IsAttached ? LogLevel.Debug : LogLevel.Information);
         });
 
+        services.AddSingleton<IMessenger>(WeakReferenceMessenger.Default);
+
         services.AddTransient<IEntityWorld, EntityWorld>();
         services.AddSingleton<IRenderDevice, OpenGLRenderDevice>();
 
diff --git a/FinalEngine.Editor.Desktop/Styles/Controls/TextBoxStyle.xaml b/FinalEngine.Editor.Desktop/Styles/Controls/TextBoxStyle.xaml
index 2453aa97..ae5f74dd 100644
--- a/FinalEngine.Editor.Desktop/Styles/Controls/TextBoxStyle.xaml
+++ b/FinalEngine.Editor.Desktop/Styles/Controls/TextBoxStyle.xaml
@@ -6,6 +6,7 @@
     <Style TargetType="{x:Type TextBox}" BasedOn="{StaticResource MahApps.Styles.TextBox.VisualStudio}">
         <Setter Property="Margin" Value="5" />
         <Setter Property="MinHeight" Value="25" />
+        <Setter Property="MinWidth" Value="250" />
         <Setter Property="VerticalContentAlignment" Value="Center" />
         <Setter Property="BorderBrush" Value="{StaticResource MahApps.Brushes.TextBox.Border}" />
         <Style.Triggers>
diff --git a/FinalEngine.Editor.Desktop/Views/Dialogs/Entities/CreateEntityView.xaml b/FinalEngine.Editor.Desktop/Views/Dialogs/Entities/CreateEntityView.xaml
index 32c42350..cfae2d6f 100644
--- a/FinalEngine.Editor.Desktop/Views/Dialogs/Entities/CreateEntityView.xaml
+++ b/FinalEngine.Editor.Desktop/Views/Dialogs/Entities/CreateEntityView.xaml
@@ -26,10 +26,10 @@
         </Grid.RowDefinitions>
 
         <Label Grid.Row="0" Content="GUID:" />
-        <TextBox Grid.Column="1" Grid.Row="0" MinWidth="250" IsEnabled="False" Text="{Binding EntityGuid, Mode=OneWay}" />
+        <TextBox Grid.Column="1" Grid.Row="0" IsEnabled="False" Text="{Binding EntityGuid, Mode=OneWay}" />
 
         <Label Grid.Row="1" Content="Entity Name:" />
-        <TextBox x:Name="textBox" Grid.Column="1" Grid.Row="1" MinWidth="250" Text="{Binding EntityName, UpdateSourceTrigger=PropertyChanged}" />
+        <TextBox x:Name="textBox" Grid.Column="1" Grid.Row="1" Text="{Binding EntityName, UpdateSourceTrigger=PropertyChanged}" />
 
         <WrapPanel Grid.Row="2" Grid.ColumnSpan="2" HorizontalAlignment="Right">
             <Button IsDefault="True" Content="Create" Command="{Binding CreateCommand}" CommandParameter="{Binding ElementName=Window}" />
diff --git a/FinalEngine.Editor.Desktop/Views/Dialogs/Layout/SaveWindowLayoutView.xaml b/FinalEngine.Editor.Desktop/Views/Dialogs/Layout/SaveWindowLayoutView.xaml
index 8c687aba..6cb859e1 100644
--- a/FinalEngine.Editor.Desktop/Views/Dialogs/Layout/SaveWindowLayoutView.xaml
+++ b/FinalEngine.Editor.Desktop/Views/Dialogs/Layout/SaveWindowLayoutView.xaml
@@ -25,7 +25,7 @@
         </Grid.RowDefinitions>
 
         <Label Grid.Row="0" Content="Layout Name:" />
-        <TextBox x:Name="textBox" Grid.Column="1" Grid.Row="0" MinWidth="250" Text="{Binding LayoutName, UpdateSourceTrigger=PropertyChanged}" />
+        <TextBox x:Name="textBox" Grid.Column="1" Grid.Row="0" Text="{Binding LayoutName, UpdateSourceTrigger=PropertyChanged}" />
 
         <WrapPanel Grid.Row="2" Grid.ColumnSpan="2" HorizontalAlignment="Right">
             <Button IsDefault="True" Content="Save" Command="{Binding SaveCommand}" CommandParameter="{Binding ElementName=Window}" />
diff --git a/FinalEngine.Editor.Desktop/Views/Docking/DockView.xaml b/FinalEngine.Editor.Desktop/Views/Docking/DockView.xaml
index 7753dbf6..ff3a2528 100644
--- a/FinalEngine.Editor.Desktop/Views/Docking/DockView.xaml
+++ b/FinalEngine.Editor.Desktop/Views/Docking/DockView.xaml
@@ -62,7 +62,7 @@
                     <!-- PROPERTIES -->
                     <data:PaneTemplateSelector.PropertiesTemplate>
                         <DataTemplate>
-                            <inspectors:ConsoleView />
+                            <inspectors:PropertiesView />
                         </DataTemplate>
                     </data:PaneTemplateSelector.PropertiesTemplate>
 
diff --git a/FinalEngine.Editor.Desktop/Views/Inspectors/EntityInspectorView.xaml b/FinalEngine.Editor.Desktop/Views/Inspectors/EntityInspectorView.xaml
new file mode 100644
index 00000000..60f971a6
--- /dev/null
+++ b/FinalEngine.Editor.Desktop/Views/Inspectors/EntityInspectorView.xaml
@@ -0,0 +1,9 @@
+<UserControl x:Class="FinalEngine.Editor.Desktop.Views.Inspectors.EntityInspectorView"
+             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+             mc:Ignorable="d">
+    <Grid>
+    </Grid>
+</UserControl>
diff --git a/FinalEngine.Editor.Desktop/Views/Inspectors/EntityInspectorView.xaml.cs b/FinalEngine.Editor.Desktop/Views/Inspectors/EntityInspectorView.xaml.cs
new file mode 100644
index 00000000..7d59ddbe
--- /dev/null
+++ b/FinalEngine.Editor.Desktop/Views/Inspectors/EntityInspectorView.xaml.cs
@@ -0,0 +1,21 @@
+// <copyright file="EntityInspectorView.xaml.cs" company="Software Antics">
+// Copyright (c) Software Antics. All rights reserved.
+// </copyright>
+
+namespace FinalEngine.Editor.Desktop.Views.Inspectors;
+
+using System.Windows.Controls;
+
+/// <summary>
+/// Interaction logic for EntityInspectorView.xaml.
+/// </summary>
+public partial class EntityInspectorView : UserControl
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="EntityInspectorView"/> class.
+    /// </summary>
+    public EntityInspectorView()
+    {
+        this.InitializeComponent();
+    }
+}
diff --git a/FinalEngine.Editor.Desktop/Views/Inspectors/PropertiesView.xaml b/FinalEngine.Editor.Desktop/Views/Inspectors/PropertiesView.xaml
index a3550d18..d5a5aa4c 100644
--- a/FinalEngine.Editor.Desktop/Views/Inspectors/PropertiesView.xaml
+++ b/FinalEngine.Editor.Desktop/Views/Inspectors/PropertiesView.xaml
@@ -3,9 +3,19 @@
              xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+             xmlns:inspectors="clr-namespace:FinalEngine.Editor.Desktop.Views.Inspectors"
              xmlns:vm="clr-namespace:FinalEngine.Editor.ViewModels.Docking.Tools.Inspectors;assembly=FinalEngine.Editor.ViewModels"
+             xmlns:vme="clr-namespace:FinalEngine.Editor.ViewModels.Inspectors;assembly=FinalEngine.Editor.ViewModels"
              mc:Ignorable="d"
              d:DataContext="{d:DesignInstance Type=vm:PropertiesToolViewModel}">
+
+    <UserControl.Resources>
+        <DataTemplate DataType="{x:Type vme:EntityInspectorViewModel}">
+            <inspectors:EntityInspectorView />
+        </DataTemplate>
+    </UserControl.Resources>
+
     <Grid>
+        <ContentControl Content="{Binding CurrentViewModel}" />
     </Grid>
 </UserControl>
diff --git a/FinalEngine.Editor.Desktop/Views/Scenes/SceneHierarchyView.xaml b/FinalEngine.Editor.Desktop/Views/Scenes/SceneHierarchyView.xaml
index 85a566e3..56d30cd2 100644
--- a/FinalEngine.Editor.Desktop/Views/Scenes/SceneHierarchyView.xaml
+++ b/FinalEngine.Editor.Desktop/Views/Scenes/SceneHierarchyView.xaml
@@ -9,7 +9,8 @@
     <Grid>
         <ListBox ItemsSource="{Binding Entities, UpdateSourceTrigger=PropertyChanged}"
                  ScrollViewer.VerticalScrollBarVisibility="Auto"
-                 ScrollViewer.HorizontalScrollBarVisibility="Disabled">
+                 ScrollViewer.HorizontalScrollBarVisibility="Disabled"
+                 SelectedItem="{Binding SelectedEntity}">
 
             <ListBox.Style>
                 <Style TargetType="ListBox" BasedOn="{StaticResource MahApps.Styles.ListBox.VisualStudio}">
diff --git a/FinalEngine.Editor.ViewModels/Docking/Tools/Inspectors/IPropertiesToolViewModel.cs b/FinalEngine.Editor.ViewModels/Docking/Tools/Inspectors/IPropertiesToolViewModel.cs
index 5abd6fb8..48d5fe3b 100644
--- a/FinalEngine.Editor.ViewModels/Docking/Tools/Inspectors/IPropertiesToolViewModel.cs
+++ b/FinalEngine.Editor.ViewModels/Docking/Tools/Inspectors/IPropertiesToolViewModel.cs
@@ -4,10 +4,19 @@
 
 namespace FinalEngine.Editor.ViewModels.Docking.Tools.Inspectors;
 
+using CommunityToolkit.Mvvm.ComponentModel;
+
 /// <summary>
 /// Defines an interface that represents a model of a properties tool view.
 /// </summary>
-/// <seealso cref="FinalEngine.Editor.ViewModels.Docking.Tools.IToolViewModel" />
+/// <seealso cref="IToolViewModel" />
 public interface IPropertiesToolViewModel : IToolViewModel
 {
+    /// <summary>
+    /// Gets the current view model.
+    /// </summary>
+    /// <value>
+    /// The current view model.
+    /// </value>
+    ObservableObject? CurrentViewModel { get; }
 }
diff --git a/FinalEngine.Editor.ViewModels/Docking/Tools/Inspectors/PropertiesToolViewModel.cs b/FinalEngine.Editor.ViewModels/Docking/Tools/Inspectors/PropertiesToolViewModel.cs
index 375cf426..0956bd39 100644
--- a/FinalEngine.Editor.ViewModels/Docking/Tools/Inspectors/PropertiesToolViewModel.cs
+++ b/FinalEngine.Editor.ViewModels/Docking/Tools/Inspectors/PropertiesToolViewModel.cs
@@ -5,6 +5,11 @@
 namespace FinalEngine.Editor.ViewModels.Docking.Tools.Inspectors;
 
 using System;
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Messaging;
+using FinalEngine.ECS.Components.Core;
+using FinalEngine.Editor.ViewModels.Inspectors;
+using FinalEngine.Editor.ViewModels.Messages.Entities;
 using Microsoft.Extensions.Logging;
 
 /// <summary>
@@ -14,22 +19,71 @@ namespace FinalEngine.Editor.ViewModels.Docking.Tools.Inspectors;
 /// <seealso cref="IPropertiesToolViewModel" />
 public sealed class PropertiesToolViewModel : ToolViewModelBase, IPropertiesToolViewModel
 {
+    /// <summary>
+    /// The logger.
+    /// </summary>
+    private readonly ILogger<PropertiesToolViewModel> logger;
+
+    /// <summary>
+    /// The messenger.
+    /// </summary>
+    private readonly IMessenger messenger;
+
+    /// <summary>
+    /// The current view model to be shown in the properties view.
+    /// </summary>
+    private ObservableObject? currentViewModel;
+
     /// <summary>
     /// Initializes a new instance of the <see cref="PropertiesToolViewModel"/> class.
     /// </summary>
     /// <param name="logger">
     /// The logger.
     /// </param>
-    public PropertiesToolViewModel(ILogger<PropertiesToolViewModel> logger)
+    /// <param name="messenger">
+    /// The messenger.
+    /// </param>
+    public PropertiesToolViewModel(
+        ILogger<PropertiesToolViewModel> logger,
+        IMessenger messenger)
     {
-        if (logger == null)
-        {
-            throw new ArgumentNullException(nameof(logger));
-        }
+        this.logger = logger ?? throw new ArgumentNullException(nameof(logger));
+        this.messenger = messenger ?? throw new ArgumentNullException(nameof(messenger));
 
         this.Title = "Properties";
         this.ContentID = "Properties";
 
         logger.LogInformation($"Initializing {this.Title}...");
+
+        this.messenger.Register<EntitySelectedMessage>(this, this.HandleEntitySelected);
+    }
+
+    /// <inheritdoc/>
+    public ObservableObject? CurrentViewModel
+    {
+        get { return this.currentViewModel; }
+        private set { this.SetProperty(ref this.currentViewModel, value); }
+    }
+
+    /// <summary>
+    /// Handles the <see cref="EntitySelectedMessage"/> and updates the view.
+    /// </summary>
+    /// <param name="recipient">
+    /// The recipient.
+    /// </param>
+    /// <param name="message">
+    /// The message.
+    /// </param>
+    /// <exception cref="System.ArgumentNullException">
+    /// The specified <paramref name="message"/> parameter cannot be null.
+    /// </exception>
+    private void HandleEntitySelected(object recipient, EntitySelectedMessage message)
+    {
+        this.logger.LogInformation($"Changing properties view to: '{nameof(EntityInspectorViewModel)}'.");
+
+        var entity = message.Entity;
+
+        this.Title = $"Entity Inspector - {entity.GetComponent<TagComponent>().Tag}";
+        this.CurrentViewModel = new EntityInspectorViewModel();
     }
 }
diff --git a/FinalEngine.Editor.ViewModels/Docking/Tools/Scenes/ISceneHierarchyToolViewModel.cs b/FinalEngine.Editor.ViewModels/Docking/Tools/Scenes/ISceneHierarchyToolViewModel.cs
index e4973676..62a715f4 100644
--- a/FinalEngine.Editor.ViewModels/Docking/Tools/Scenes/ISceneHierarchyToolViewModel.cs
+++ b/FinalEngine.Editor.ViewModels/Docking/Tools/Scenes/ISceneHierarchyToolViewModel.cs
@@ -10,7 +10,7 @@ namespace FinalEngine.Editor.ViewModels.Docking.Tools.Scenes;
 /// <summary>
 /// Defines an interface that represents a model of a scene hierarchy tool view.
 /// </summary>
-/// <seealso cref="FinalEngine.Editor.ViewModels.Docking.Tools.IToolViewModel" />
+/// <seealso cref="IToolViewModel" />
 public interface ISceneHierarchyToolViewModel : IToolViewModel
 {
     /// <summary>
@@ -20,4 +20,12 @@ public interface ISceneHierarchyToolViewModel : IToolViewModel
     /// The entities within the active scene.
     /// </value>
     IReadOnlyCollection<Entity> Entities { get; }
+
+    /// <summary>
+    /// Gets or sets the selected entity.
+    /// </summary>
+    /// <value>
+    /// The selected entity.
+    /// </value>
+    Entity? SelectedEntity { get; set; }
 }
diff --git a/FinalEngine.Editor.ViewModels/Docking/Tools/Scenes/SceneHierarchyToolViewModel.cs b/FinalEngine.Editor.ViewModels/Docking/Tools/Scenes/SceneHierarchyToolViewModel.cs
index 004152cb..31610770 100644
--- a/FinalEngine.Editor.ViewModels/Docking/Tools/Scenes/SceneHierarchyToolViewModel.cs
+++ b/FinalEngine.Editor.ViewModels/Docking/Tools/Scenes/SceneHierarchyToolViewModel.cs
@@ -6,8 +6,10 @@ namespace FinalEngine.Editor.ViewModels.Docking.Tools.Scenes;
 
 using System;
 using System.Collections.Generic;
+using CommunityToolkit.Mvvm.Messaging;
 using FinalEngine.ECS;
 using FinalEngine.Editor.Common.Services.Scenes;
+using FinalEngine.Editor.ViewModels.Messages.Entities;
 using Microsoft.Extensions.Logging;
 
 /// <summary>
@@ -17,30 +19,47 @@ namespace FinalEngine.Editor.ViewModels.Docking.Tools.Scenes;
 /// <seealso cref="ISceneHierarchyToolViewModel" />
 public sealed class SceneHierarchyToolViewModel : ToolViewModelBase, ISceneHierarchyToolViewModel
 {
+    /// <summary>
+    /// The messenger.
+    /// </summary>
+    private readonly IMessenger messenger;
+
     /// <summary>
     /// The scene manager.
     /// </summary>
     private readonly ISceneManager sceneManager;
 
+    /// <summary>
+    /// The selected entity, or <c>null</c> if one is not selected.
+    /// </summary>
+    private Entity? selectedEntity;
+
     /// <summary>
     /// Initializes a new instance of the <see cref="SceneHierarchyToolViewModel"/> class.
     /// </summary>
     /// <param name="logger">
     /// The logger.
     /// </param>
+    /// <param name="messenger">
+    /// The messenger.
+    /// </param>
     /// <param name="sceneManager">
     /// The scene manager.
     /// </param>
     /// <exception cref="ArgumentNullException">
-    /// The specified <paramref name="logger"/> or <paramref name="sceneManager"/> parameter cannot be null.
+    /// The specified <paramref name="logger"/>, <paramref name="messenger"/> or <paramref name="sceneManager"/> parameter cannot be null.
     /// </exception>
-    public SceneHierarchyToolViewModel(ILogger<SceneHierarchyToolViewModel> logger, ISceneManager sceneManager)
+    public SceneHierarchyToolViewModel(
+        ILogger<SceneHierarchyToolViewModel> logger,
+        IMessenger messenger,
+        ISceneManager sceneManager)
     {
         if (logger == null)
         {
             throw new ArgumentNullException(nameof(logger));
         }
 
+        this.messenger = messenger ?? throw new ArgumentNullException(nameof(messenger));
         this.sceneManager = sceneManager ?? throw new ArgumentNullException(nameof(sceneManager));
 
         this.Title = "Scene Hierarchy";
@@ -54,4 +73,23 @@ public IReadOnlyCollection<Entity> Entities
     {
         get { return this.sceneManager.ActiveScene.Entities; }
     }
+
+    /// <inheritdoc/>
+    public Entity? SelectedEntity
+    {
+        get
+        {
+            return this.selectedEntity;
+        }
+
+        set
+        {
+            this.SetProperty(ref this.selectedEntity, value);
+
+            if (this.SelectedEntity != null)
+            {
+                this.messenger.Send(new EntitySelectedMessage(this.SelectedEntity));
+            }
+        }
+    }
 }
diff --git a/FinalEngine.Editor.ViewModels/Inspectors/EntityInspectorViewModel.cs b/FinalEngine.Editor.ViewModels/Inspectors/EntityInspectorViewModel.cs
new file mode 100644
index 00000000..91836e52
--- /dev/null
+++ b/FinalEngine.Editor.ViewModels/Inspectors/EntityInspectorViewModel.cs
@@ -0,0 +1,16 @@
+// <copyright file="EntityInspectorViewModel.cs" company="Software Antics">
+// Copyright (c) Software Antics. All rights reserved.
+// </copyright>
+
+namespace FinalEngine.Editor.ViewModels.Inspectors;
+
+using CommunityToolkit.Mvvm.ComponentModel;
+
+/// <summary>
+/// Provides a standard implementation of an <see cref="IEntityInspectorViewModel"/>.
+/// </summary>
+/// <seealso cref="ObservableObject" />
+/// <seealso cref="IEntityInspectorViewModel" />
+public sealed class EntityInspectorViewModel : ObservableObject, IEntityInspectorViewModel
+{
+}
diff --git a/FinalEngine.Editor.ViewModels/Inspectors/IEntityInspectorViewModel.cs b/FinalEngine.Editor.ViewModels/Inspectors/IEntityInspectorViewModel.cs
new file mode 100644
index 00000000..a72b41aa
--- /dev/null
+++ b/FinalEngine.Editor.ViewModels/Inspectors/IEntityInspectorViewModel.cs
@@ -0,0 +1,15 @@
+// <copyright file="IEntityInspectorViewModel.cs" company="Software Antics">
+// Copyright (c) Software Antics. All rights reserved.
+// </copyright>
+
+namespace FinalEngine.Editor.ViewModels.Inspectors;
+
+using System.Diagnostics.CodeAnalysis;
+
+/// <summary>
+/// Defines an interface that represents a model of the entity inspector view.
+/// </summary>
+[SuppressMessage("Design", "CA1040:Avoid empty interfaces", Justification = "TODO")]
+public interface IEntityInspectorViewModel
+{
+}
diff --git a/FinalEngine.Editor.ViewModels/Messages/Entities/EntitySelectedMessage.cs b/FinalEngine.Editor.ViewModels/Messages/Entities/EntitySelectedMessage.cs
new file mode 100644
index 00000000..a480c219
--- /dev/null
+++ b/FinalEngine.Editor.ViewModels/Messages/Entities/EntitySelectedMessage.cs
@@ -0,0 +1,36 @@
+// <copyright file="EntitySelectedMessage.cs" company="Software Antics">
+// Copyright (c) Software Antics. All rights reserved.
+// </copyright>
+
+namespace FinalEngine.Editor.ViewModels.Messages.Entities;
+
+using System;
+using FinalEngine.ECS;
+
+/// <summary>
+/// Provides a message that should be published when an entity has been selected within the scene hierarchy.
+/// </summary>
+public sealed class EntitySelectedMessage
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="EntitySelectedMessage"/> class.
+    /// </summary>
+    /// <param name="entity">
+    /// The entity that has been selected.
+    /// </param>
+    /// <exception cref="ArgumentNullException">
+    /// The specified <paramref name="entity"/> parameter cannot be null.
+    /// </exception>
+    public EntitySelectedMessage(Entity entity)
+    {
+        this.Entity = entity ?? throw new ArgumentNullException(nameof(entity));
+    }
+
+    /// <summary>
+    /// Gets the entity that has been selected.
+    /// </summary>
+    /// <value>
+    /// The entity that has been selected.
+    /// </value>
+    public Entity Entity { get; }
+}
diff --git a/FinalEngine.Tests/Editor/ViewModels/Docking/Tools/Inspectors/PropertiesToolViewModelTests.cs b/FinalEngine.Tests/Editor/ViewModels/Docking/Tools/Inspectors/PropertiesToolViewModelTests.cs
index 358026b5..e69ac413 100644
--- a/FinalEngine.Tests/Editor/ViewModels/Docking/Tools/Inspectors/PropertiesToolViewModelTests.cs
+++ b/FinalEngine.Tests/Editor/ViewModels/Docking/Tools/Inspectors/PropertiesToolViewModelTests.cs
@@ -5,7 +5,12 @@
 namespace FinalEngine.Tests.Editor.ViewModels.Docking.Tools.Inspectors;
 
 using System;
+using CommunityToolkit.Mvvm.Messaging;
+using FinalEngine.ECS;
+using FinalEngine.ECS.Components.Core;
 using FinalEngine.Editor.ViewModels.Docking.Tools.Inspectors;
+using FinalEngine.Editor.ViewModels.Inspectors;
+using FinalEngine.Editor.ViewModels.Messages.Entities;
 using Microsoft.Extensions.Logging;
 using Moq;
 using NUnit.Framework;
@@ -49,14 +54,56 @@ public void ConstructorShouldThrowArgumentNullExceptionWhenLoggerIsNull()
         // Act and assert
         Assert.Throws<ArgumentNullException>(() =>
         {
-            new PropertiesToolViewModel(null);
+            new PropertiesToolViewModel(null, WeakReferenceMessenger.Default);
         });
     }
 
+    [Test]
+    public void ConstructorShouldThrowArgumentNullExceptionWhenMessengerIsNull()
+    {
+        // Act and assert
+        Assert.Throws<ArgumentNullException>(() =>
+        {
+            new PropertiesToolViewModel(this.logger.Object, null);
+        });
+    }
+
+    [Test]
+    public void MessengerPubilshShouldSetCurrentViewToEntityInspectorViewModelWhenInvoked()
+    {
+        // Arrange
+        var entity = new Entity();
+        entity.AddComponent<TagComponent>();
+
+        // Act
+        WeakReferenceMessenger.Default.Send(new EntitySelectedMessage(entity));
+
+        // Assert
+        Assert.That(this.viewModel.CurrentViewModel, Is.TypeOf<EntityInspectorViewModel>());
+    }
+
+    [Test]
+    public void MessengerPubilshShouldSetTitleToEntityInspectorWhenInvoked()
+    {
+        // Arrange
+        var entity = new Entity();
+
+        entity.AddComponent(new TagComponent()
+        {
+            Tag = "Tag",
+        });
+
+        // Act
+        WeakReferenceMessenger.Default.Send(new EntitySelectedMessage(entity));
+
+        // Assert
+        Assert.That(this.viewModel.Title, Is.EqualTo("Entity Inspector - Tag"));
+    }
+
     [SetUp]
     public void Setup()
     {
         this.logger = new Mock<ILogger<PropertiesToolViewModel>>();
-        this.viewModel = new PropertiesToolViewModel(this.logger.Object);
+        this.viewModel = new PropertiesToolViewModel(this.logger.Object, WeakReferenceMessenger.Default);
     }
 }
diff --git a/FinalEngine.Tests/Editor/ViewModels/Docking/Tools/Scenes/SceneHierarchyToolViewModelTests.cs b/FinalEngine.Tests/Editor/ViewModels/Docking/Tools/Scenes/SceneHierarchyToolViewModelTests.cs
index 410ce3bc..f8c7b319 100644
--- a/FinalEngine.Tests/Editor/ViewModels/Docking/Tools/Scenes/SceneHierarchyToolViewModelTests.cs
+++ b/FinalEngine.Tests/Editor/ViewModels/Docking/Tools/Scenes/SceneHierarchyToolViewModelTests.cs
@@ -6,6 +6,7 @@ namespace FinalEngine.Tests.Editor.ViewModels.Docking.Tools.Scenes;
 
 using System;
 using System.Collections.Generic;
+using CommunityToolkit.Mvvm.Messaging;
 using FinalEngine.ECS;
 using FinalEngine.Editor.Common.Models.Scenes;
 using FinalEngine.Editor.Common.Services.Scenes;
@@ -21,6 +22,8 @@ public sealed class SceneHierarchyToolViewModelTests
 
     private Mock<ILogger<SceneHierarchyToolViewModel>> logger;
 
+    private Mock<IMessenger> messenger;
+
     private Mock<IScene> scene;
 
     private Mock<ISceneManager> sceneManager;
@@ -59,7 +62,17 @@ public void ConstructorShouldThrowArgumentNullExceptionWhenLoggerIsNull()
         // Act and assert
         Assert.Throws<ArgumentNullException>(() =>
         {
-            new SceneHierarchyToolViewModel(null, this.sceneManager.Object);
+            new SceneHierarchyToolViewModel(null, WeakReferenceMessenger.Default, this.sceneManager.Object);
+        });
+    }
+
+    [Test]
+    public void ConstructorShouldThrowArgumentNullExceptionWhenMessengerIsNull()
+    {
+        // Act and assert
+        Assert.Throws<ArgumentNullException>(() =>
+        {
+            new SceneHierarchyToolViewModel(this.logger.Object, null, this.sceneManager.Object);
         });
     }
 
@@ -69,7 +82,7 @@ public void ConstructorShouldThrowArgumentNullExceptionWhenSceneManagerIsNull()
         // Act and assert
         Assert.Throws<ArgumentNullException>(() =>
         {
-            new SceneHierarchyToolViewModel(this.logger.Object, null);
+            new SceneHierarchyToolViewModel(this.logger.Object, WeakReferenceMessenger.Default, null);
         });
     }
 
@@ -83,12 +96,37 @@ public void EntitiesShouldReturnActiveEntitiesWhenInvoked()
         Assert.That(actual, Is.SameAs(this.entities));
     }
 
+    [Test]
+    public void SelectedEntityShouldReturnEntityWhenSetToEntity()
+    {
+        // Arrange
+        var expected = new Entity();
+        this.viewModel.SelectedEntity = expected;
+
+        // Act
+        var actual = this.viewModel.SelectedEntity;
+
+        // Assert
+        Assert.That(actual, Is.SameAs(expected));
+    }
+
+    [Test]
+    public void SelectedEntityShouldReturnNullWhenNotSet()
+    {
+        // Act
+        var actual = this.viewModel.SelectedEntity;
+
+        // Assert
+        Assert.That(actual, Is.Null);
+    }
+
     [SetUp]
     public void Setup()
     {
         this.logger = new Mock<ILogger<SceneHierarchyToolViewModel>>();
         this.sceneManager = new Mock<ISceneManager>();
         this.scene = new Mock<IScene>();
+        this.messenger = new Mock<IMessenger>();
 
         this.entities = new List<Entity>()
         {
@@ -100,6 +138,6 @@ public void Setup()
         this.sceneManager.SetupGet(x => x.ActiveScene).Returns(this.scene.Object);
         this.scene.SetupGet(x => x.Entities).Returns((IReadOnlyCollection<Entity>)this.entities);
 
-        this.viewModel = new SceneHierarchyToolViewModel(this.logger.Object, this.sceneManager.Object);
+        this.viewModel = new SceneHierarchyToolViewModel(this.logger.Object, this.messenger.Object, this.sceneManager.Object);
     }
 }
diff --git a/SharedAssemblyInfo.cs b/SharedAssemblyInfo.cs
index 41e64df6..8cafab86 100644
--- a/SharedAssemblyInfo.cs
+++ b/SharedAssemblyInfo.cs
@@ -9,8 +9,8 @@
 [assembly: AssemblyCopyright("© 2023 Software Antics")]
 [assembly: AssemblyTrademark("Software Antics™")]
 [assembly: AssemblyCulture("")]
-[assembly: AssemblyVersion("2023.3.2618.0")]
-[assembly: AssemblyFileVersion("2023.3.2617.0")]
+[assembly: AssemblyVersion("2023.3.2885.0")]
+[assembly: AssemblyFileVersion("2023.3.2884.0")]
 #if DEBUG
 [assembly: AssemblyConfiguration("Debug")]
 #else