Created basic tray icon, and switched the app to use it on startup.

Author: Sypwn

WinAudioAssistant/App.xaml

@@ -1,8 +1,7 @@
 <Application x:Class="WinAudioAssistant.App"
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-             xmlns:local="clr-namespace:WinAudioAssistant"
-             StartupUri="Views\DevicePriorityView.xaml">
+             xmlns:local="clr-namespace:WinAudioAssistant">
     <Application.Resources>
 
     </Application.Resources>

WinAudioAssistant/App.xaml.cs

@@ -3,6 +3,7 @@
 using System.Windows;
 using WinAudioAssistant.Models;
 using AudioSwitcher.AudioApi.CoreAudio;
+using WinAudioAssistant.Views;
 
 namespace WinAudioAssistant
 {
@@ -29,9 +30,9 @@ protected override void OnStartup(StartupEventArgs e)
             base.OnStartup(e);
 
             UserSettings = UserSettings.LoadAtStartup();
-
             SystemEventsHandler.RegisterAllEvents();
             AudioEndpointManager.UpdateCachedEndpoints();
+            new TrayIconView();
         }
     }
 

WinAudioAssistant/Resources/Icons/Icon1.ico

@@ -0,0 +1,44 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows.Input;
+using WinAudioAssistant.Views;
+
+namespace WinAudioAssistant.ViewModels
+{
+    class TrayIconViewModel
+    {
+
+        public ICommand DoubleClickCommand { get; }
+        public ICommand SettingsCommand { get; }
+        public ICommand ExitCommand { get; }
+
+        public TrayIconViewModel()
+        {
+            DoubleClickCommand = new RelayCommand(Settings);
+            SettingsCommand = new RelayCommand(Settings);
+            ExitCommand = new RelayCommand(Exit);
+        }
+
+        private void Settings(object? parameter)
+        {
+            foreach (var window in App.Current.Windows)
+            {
+                if (window is DevicePriorityView devicePriorityView)
+                {
+                    devicePriorityView.Focus();
+                    return;
+                }
+            }
+            new DevicePriorityView().Show();
+        }
+
+        private void Exit(object? parameter)
+        {
+            App.Current.Shutdown();
+        }
+
+    }
+}

WinAudioAssistant/ViewModels/TrayIconViewModel.cs

@@ -0,0 +1,26 @@
+<Window x:Class="WinAudioAssistant.Views.TrayIconView"
+      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
+      xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
+      xmlns:tb="http://www.hardcodet.net/taskbar"
+      xmlns:local="clr-namespace:WinAudioAssistant.Views"
+      xmlns:viewmodels="clr-namespace:WinAudioAssistant.ViewModels"
+      mc:Ignorable="d" 
+      d:DesignHeight="450" d:DesignWidth="800"
+      Title="TrayIcon">
+    <Window.DataContext>
+        <viewmodels:TrayIconViewModel/>
+    </Window.DataContext>
+    <Grid>
+        <tb:TaskbarIcon IconSource="/Resources/Icons/Icon1.ico" ToolTipText="WinAudioAssistant"
+                        DoubleClickCommand="{Binding DoubleClickCommand}" >
+            <tb:TaskbarIcon.ContextMenu>
+                <ContextMenu>
+                    <MenuItem Header="Settings" Command="{Binding SettingsCommand}" />
+                    <MenuItem Header="Exit" Command="{Binding ExitCommand}" />
+                </ContextMenu>
+            </tb:TaskbarIcon.ContextMenu>
+        </tb:TaskbarIcon>
+    </Grid>
+</Window>

WinAudioAssistant/Views/TrayIconView.xaml

@@ -0,0 +1,27 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Data;
+using System.Windows.Documents;
+using System.Windows.Input;
+using System.Windows.Media;
+using System.Windows.Media.Imaging;
+using System.Windows.Shapes;
+
+namespace WinAudioAssistant.Views
+{
+    /// <summary>
+    /// Interaction logic for TrayIconView.xaml
+    /// </summary>
+    public partial class TrayIconView : Window
+    {
+        public TrayIconView()
+        {
+            InitializeComponent();
+        }
+    }
+}

WinAudioAssistant/Views/TrayIconView.xaml.cs

@@ -9,11 +9,13 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <None Remove="Resources\Icons\Icon1.ico" />
     <None Remove="Resources\Icons\MissingFile.ico" />
   </ItemGroup>
 
   <ItemGroup>
     <PackageReference Include="gong-wpf-dragdrop" Version="3.2.1" />
+    <PackageReference Include="Hardcodet.NotifyIcon.Wpf" Version="1.1.0" />
     <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
     <PackageReference Include="System.Reactive" Version="6.0.0" />
   </ItemGroup>
@@ -43,6 +45,7 @@
   </ItemGroup>
 
   <ItemGroup>
+    <Resource Include="Resources\Icons\Icon1.ico" />
     <Resource Include="Resources\Icons\MissingFile.ico" />
   </ItemGroup>
 </Project>