Enable drag and drop support

RedBookPlayer/GUI/MainWindow.xaml

@@ -1,6 +1,7 @@
 <Window xmlns="https://github.com/avaloniaui" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d"
-        x:Class="RedBookPlayer.GUI.MainWindow" Title="RedBookPlayer" SizeToContent="WidthAndHeight">
+        x:Class="RedBookPlayer.GUI.MainWindow" Title="RedBookPlayer" SizeToContent="WidthAndHeight"
+        DragDrop.AllowDrop="True">
     <ContentControl Name="Content" />
 </Window>

RedBookPlayer/GUI/MainWindow.xaml.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Xml;
 using Avalonia.Controls;
@@ -62,15 +63,9 @@ namespace RedBookPlayer.GUI
             Instance.Height = ((PlayerView)Instance.ContentControl.Content).Height;
         }
 
-        public void OnKeyDown(object sender, KeyEventArgs e)
-        {
-            if(e.Key == Key.F1)
-            {
-                settingsWindow = new SettingsWindow(App.Settings);
-                settingsWindow.Show();
-            }
-        }
-
+        /// <summary>
+        /// Initialize the main window
+        /// </summary>
         void InitializeComponent()
         {
             AvaloniaXamlLoader.Load(this);
@@ -97,6 +92,36 @@ namespace RedBookPlayer.GUI
             {
                 PlayerView.Player.Stop();
             };
+
+            AddHandler(DragDrop.DropEvent, MainWindow_Drop);
         }
+
+        #region Event Handlers
+
+        public async void MainWindow_Drop(object sender, DragEventArgs e)
+        {
+            PlayerView playerView = ContentControl.Content as PlayerView;
+            if(playerView == null)
+                return;
+
+            IEnumerable<string> fileNames = e.Data.GetFileNames();
+            foreach(string filename in fileNames)
+            {
+                bool loaded = await playerView.LoadImage(filename);
+                if(loaded)
+                    break;
+            }
+        }
+
+        public void OnKeyDown(object sender, KeyEventArgs e)
+        {
+            if(e.Key == Key.F1)
+            {
+                settingsWindow = new SettingsWindow(App.Settings);
+                settingsWindow.Show();
+            }
+        }
+
+        #endregion
     }
 }

RedBookPlayer/GUI/PlayerView.xaml.cs

@@ -58,6 +58,29 @@ namespace RedBookPlayer.GUI
             return (await dialog.ShowAsync((Window)Parent.Parent))?.FirstOrDefault();
         }
 
+        /// <summary>
+        /// Load an image from the path
+        /// </summary>
+        /// <param name="path">Path to the image to load</param>
+        public async Task<bool> LoadImage(string path)
+        {
+            bool result = await Task.Run(() =>
+            {
+                Player.Init(path, App.Settings.AutoPlay);
+                return Player.Initialized;
+            });
+
+            if(result)
+            {
+                await Dispatcher.UIThread.InvokeAsync(() =>
+                {
+                    MainWindow.Instance.Title = "RedBookPlayer - " + path.Split('/').Last().Split('\\').Last();
+                });
+            }
+
+            return result;
+        }
+
         /// <summary>
         /// Load the png image for a given character based on the theme
         /// </summary>
@@ -90,6 +113,7 @@ namespace RedBookPlayer.GUI
         {
             DataContext = new PlayerViewModel();
 
+            // Load the theme
             if (xaml != null)
                 new AvaloniaXamlLoader().Load(xaml, null, this);
             else
@@ -150,27 +174,6 @@ namespace RedBookPlayer.GUI
             };
         }
 
-        /// <summary>
-        /// Load an image from the path
-        /// </summary>
-        /// <param name="path">Path to the image to load</param>
-        private async void LoadImage(string path)
-        {
-            bool result = await Task.Run(() =>
-            {
-                Player.Init(path, App.Settings.AutoPlay);
-                return Player.Initialized;
-            });
-
-            if(result)
-            {
-                await Dispatcher.UIThread.InvokeAsync(() =>
-                {
-                    MainWindow.Instance.Title = "RedBookPlayer - " + path.Split('/').Last().Split('\\').Last();
-                });
-            }
-        }
-
         /// <summary>
         /// Update the UI with the most recent information from the Player
         /// </summary>

RedBookPlayer/Program.cs

@@ -1,3 +1,4 @@
+using System;
 #if WindowsDebug
 using System.Runtime.InteropServices;
 #endif
@@ -8,6 +9,7 @@ namespace RedBookPlayer
 {
     internal class Program
     {
+        [STAThread]
         public static void Main(string[] args)
         {
 #if WindowsDebug