From fdeebaf32a5c90f96c1805e1c038f9359966a06e Mon Sep 17 00:00:00 2001
From: DubyaDude <ushafiq141@gmail.com>
Date: Sat, 20 Jan 2024 10:14:30 -0500
Subject: [PATCH] Fixed NRE in Sample.UI when selection is null.

---
 Sample.UI/MainWindow.xaml    |  6 +++---
 Sample.UI/MainWindow.xaml.cs | 29 ++++++++++++++++++++++-------
 2 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/Sample.UI/MainWindow.xaml b/Sample.UI/MainWindow.xaml
index 8126edd..5646b8c 100644
--- a/Sample.UI/MainWindow.xaml
+++ b/Sample.UI/MainWindow.xaml
@@ -34,9 +34,9 @@
             <Image x:Name="SongImage" Height="160" Canvas.Left="10" Canvas.Top="11" Width="160"/>
             <Label x:Name="SongTitle" Content="TITLE" Canvas.Left="179" Canvas.Top="2" Height="64" Width="449" FontSize="50" FontFamily="Segoe UI BOLD"/>
             <Label x:Name="SongAuthor" Content="Author" Canvas.Left="179" Canvas.Top="59" Height="35" Width="449" FontSize="25" FontFamily="Segoe UI"/>
-            <Button x:Name="ControlBack" Content="◀◀" Canvas.Left="179" Canvas.Top="105" Height="65" Width="65" Click="Back_Click" FontSize ="27" FontFamily="Segoe UI BOLD"/>
-            <Button x:Name="ControlPlayPause" Content="▶️" Canvas.Left="249" Canvas.Top="105" Height="65" Width="65" Click="PlayPause_Click" FontSize ="27" FontFamily="Segoe UI BOLD"/>
-            <Button x:Name="ControlForward" Content="▶️▶️" Canvas.Left="319" Canvas.Top="105" Height="65" Width="65" Click="Forward_Click" FontSize ="27" FontFamily="Segoe UI BOLD"/>
+            <Button x:Name="ControlBack" IsEnabled="False" Content="◀◀" Canvas.Left="179" Canvas.Top="105" Height="65" Width="65" Click="Back_Click" FontSize ="27" FontFamily="Segoe UI BOLD"/>
+            <Button x:Name="ControlPlayPause" IsEnabled="False" Content="▶️" Canvas.Left="249" Canvas.Top="105" Height="65" Width="65" Click="PlayPause_Click" FontSize ="27" FontFamily="Segoe UI BOLD"/>
+            <Button x:Name="ControlForward" IsEnabled="False" Content="▶️▶️" Canvas.Left="319" Canvas.Top="105" Height="65" Width="65" Click="Forward_Click" FontSize ="27" FontFamily="Segoe UI BOLD"/>
         </Canvas>
     </ui:NavigationView>
 
diff --git a/Sample.UI/MainWindow.xaml.cs b/Sample.UI/MainWindow.xaml.cs
index f012d93..0f4ed40 100644
--- a/Sample.UI/MainWindow.xaml.cs
+++ b/Sample.UI/MainWindow.xaml.cs
@@ -86,6 +86,9 @@ private void SongList_SelectionChanged(NavigationView navView, NavigationViewSel
                 currentSession.OnMediaPropertyChanged += CurrentSession_OnMediaPropertyChanged;
                 currentSession.OnPlaybackStateChanged += CurrentSession_OnPlaybackStateChanged;
                 CurrentSession_OnPlaybackStateChanged(currentSession);
+                ControlPlayPause.IsEnabled = true;
+                ControlBack.IsEnabled = true;
+                ControlForward.IsEnabled = true;
             }
             else
             {
@@ -93,6 +96,9 @@ private void SongList_SelectionChanged(NavigationView navView, NavigationViewSel
                 SongTitle.Content = "TITLE";
                 SongAuthor.Content = "Author";
                 ControlPlayPause.Content = "▶️";
+                ControlPlayPause.IsEnabled = false;
+                ControlBack.IsEnabled = false;
+                ControlForward.IsEnabled = false;
             }
         }
 
@@ -136,22 +142,31 @@ private void UpdateUI(MediaSession mediaSession)
 
         private async void Back_Click(object sender, RoutedEventArgs e)
         {
-            await currentSession?.ControlSession.TrySkipPreviousAsync();
+            if(currentSession != null)
+            {
+                await currentSession.ControlSession.TrySkipPreviousAsync();
+            }
         }
 
         private async void PlayPause_Click(object sender, RoutedEventArgs e)
         {
-            var controlsInfo = currentSession?.ControlSession.GetPlaybackInfo().Controls;
+            if (currentSession != null)
+            {
+                var controlsInfo = currentSession.ControlSession.GetPlaybackInfo().Controls;
 
-            if (controlsInfo?.IsPauseEnabled == true)
-                await currentSession?.ControlSession.TryPauseAsync();
-            else if (controlsInfo?.IsPlayEnabled == true)
-                await currentSession?.ControlSession.TryPlayAsync();
+                if (controlsInfo.IsPauseEnabled == true)
+                    await currentSession.ControlSession.TryPauseAsync();
+                else if (controlsInfo.IsPlayEnabled == true)
+                    await currentSession.ControlSession.TryPlayAsync();
+            }
         }
 
         private async void Forward_Click(object sender, RoutedEventArgs e)
         {
-            await currentSession?.ControlSession.TrySkipNextAsync();
+            if (currentSession != null)
+            {
+                await currentSession.ControlSession.TrySkipNextAsync();
+            }
         }
     }