Merge branch 'develop'

Build/MQTTnet.nuspec

@@ -2,7 +2,7 @@
 <package >
   <metadata>
     <id>MQTTnet</id>
-    <version>2.7.0</version>
+    <version>2.7.1</version>
     <authors>Christian Kratky</authors>
     <owners>Christian Kratky</owners>
     <licenseUrl>https://github.com/chkr1011/MQTTnet/blob/master/LICENSE</licenseUrl>
@@ -10,16 +10,10 @@
     <iconUrl>https://raw.githubusercontent.com/chkr1011/MQTTnet/master/Images/Logo_128x128.png</iconUrl>
     <requireLicenseAcceptance>false</requireLicenseAcceptance>
     <description>MQTTnet is a high performance .NET library for MQTT based communication. It provides a MQTT client and a MQTT server (broker).</description>
-    <releaseNotes>* [Core] Fixed some still thread blocking parts in the code (thanks to @kpreisser).
+    <releaseNotes>* [Client] The _ManagedClient_ now has an event which is fired after a queued application message was processed (including exception).
-* [Core] Updated 3rd-Party packages.
+* [Client] The _ManagedClient_ now supports unsubscribing (thanks to @lerppana)
-* [Core] Fixed wrong packet identifier calculation (thanks to @benpittoors).
+* [Server] Fixed some minor async issues.
-* [Core] Fixed an issue when reading the body of a package from a disconnected sender (thanks to @kpreisser).
+* [Server] Fixed wrong comparison of the topic and QoS for retained messages.
-* [Core] Fixed wrong parsing of the body length (thanks to @kpreisser).
-* [Client] The client interfaces are now implementing _IDisposable_.
-* [Client] The disconnected event now contains the exception which was thrown and causing the disconnect.
-* [Server] Fixed an issue which lets the server block 1 second after accepting a new connection (thanks to @kpreisser).
-* [Server] The server now allows managing client subscriptions.
-* [Server] Added events for topic subscriptions.
     </releaseNotes>
     <copyright>Copyright Christian Kratky 2016-2018</copyright>
     <tags>MQTT Message Queue Telemetry Transport MQTTClient MQTTServer Server MQTTBroker Broker NETStandard IoT InternetOfThings Messaging Hardware Arduino Sensor Actuator M2M ESP Smart Home Cities Automation Xamarin</tags> 

Build/build.ps1

@@ -1,6 +1,7 @@
 param([string]$assemblyVersion, [string]$nugetVersion)
 
-if ([string]::IsNullOrEmpty($version)) {$version = "0.0.1"}
+if ([string]::IsNullOrEmpty($assemblyVersion)) {$assemblyVersion = "0.0.1"}
+if ([string]::IsNullOrEmpty($nugetVersion)) {$nugetVersion = "0.0.1"}
 
 $vswhere = ${Env:\ProgramFiles(x86)} + '\Microsoft Visual Studio\Installer\vswhere'
 
@@ -9,14 +10,14 @@ if ($path) {
     $msbuild = join-path $path 'MSBuild\15.0\Bin\MSBuild.exe'
 
 	# Build the core library
-    &$msbuild ..\Frameworks\MQTTnet.Netstandard\MQTTnet.Netstandard.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="net452" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
+    &$msbuild ..\Frameworks\MQTTnet.Netstandard\MQTTnet.Netstandard.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="net452" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m /p:SignAssembly=true /p:AssemblyOriginatorKeyFile=".\..\..\Build\codeSigningKey.pfx"
-    &$msbuild ..\Frameworks\MQTTnet.Netstandard\MQTTnet.Netstandard.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="net461" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
+    &$msbuild ..\Frameworks\MQTTnet.Netstandard\MQTTnet.Netstandard.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="net461" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m /p:SignAssembly=true /p:AssemblyOriginatorKeyFile=".\..\..\Build\codeSigningKey.pfx"
-    &$msbuild ..\Frameworks\MQTTnet.Netstandard\MQTTnet.Netstandard.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="netstandard1.3" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
+    &$msbuild ..\Frameworks\MQTTnet.Netstandard\MQTTnet.Netstandard.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="netstandard1.3" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m /p:SignAssembly=true /p:AssemblyOriginatorKeyFile=".\..\..\Build\codeSigningKey.pfx"
-    &$msbuild ..\Frameworks\MQTTnet.Netstandard\MQTTnet.Netstandard.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="netstandard2.0" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
+    &$msbuild ..\Frameworks\MQTTnet.Netstandard\MQTTnet.Netstandard.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="netstandard2.0" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m /p:SignAssembly=true /p:AssemblyOriginatorKeyFile=".\..\..\Build\codeSigningKey.pfx"
-    &$msbuild ..\Frameworks\MQTTnet.Netstandard\MQTTnet.Netstandard.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="uap10.0" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
+    &$msbuild ..\Frameworks\MQTTnet.Netstandard\MQTTnet.Netstandard.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="uap10.0" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m /p:SignAssembly=true /p:AssemblyOriginatorKeyFile=".\..\..\Build\codeSigningKey.pfx"
     
 	# Build the ASP.NET Core 2.0 extension
-	&$msbuild ..\Frameworks\MQTTnet.AspNetCore\MQTTnet.AspNetCore.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="netstandard2.0" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
+	&$msbuild ..\Frameworks\MQTTnet.AspNetCore\MQTTnet.AspNetCore.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="netstandard2.0" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m /p:SignAssembly=true /p:AssemblyOriginatorKeyFile=".\..\..\Build\codeSigningKey.pfx"
 
 	# Build the RPC extension
 	&$msbuild ..\Extensions\MQTTnet.Extensions.Rpc\MQTTnet.Extensions.Rpc.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="net452" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
@@ -25,7 +26,8 @@ if ($path) {
     &$msbuild ..\Extensions\MQTTnet.Extensions.Rpc\MQTTnet.Extensions.Rpc.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="netstandard2.0" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
     &$msbuild ..\Extensions\MQTTnet.Extensions.Rpc\MQTTnet.Extensions.Rpc.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="uap10.0" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
 
-    Remove-Item .\NuGet -Force -Recurse
+    Remove-Item .\NuGet -Force -Recurse -ErrorAction SilentlyContinue
+
     New-Item -ItemType Directory -Force -Path .\NuGet
     .\NuGet.exe pack MQTTnet.nuspec -Verbosity detailed -Symbols -OutputDir "NuGet" -Version $nugetVersion
     .\NuGet.exe pack MQTTnet.AspNetCore.nuspec -Verbosity detailed -Symbols -OutputDir "NuGet" -Version $nugetVersion

Documents/Import_CodeSigningKey.md

@@ -3,4 +3,7 @@ In order to import the key for code signing on a new developer machine use the f
 
 > sn –i codeSigningKey.pfx VS_KEY_EFCA4C5B6DFD4B4F
 
-The container name may be different.
+The container name may be different.
+
+# Check if the assembly has a strong name
+> sn -vf MQTTnet.dll

Extensions/MQTTnet.Extensions.Rpc/MQTTnet.Extensions.Rpc.csproj

@@ -20,6 +20,7 @@
     <TargetFrameworkIdentifier>.NETCore</TargetFrameworkIdentifier>
     <TargetFrameworkVersion>v5.0</TargetFrameworkVersion>
     <DefineConstants>$(DefineConstants);WINDOWS_UWP</DefineConstants>
+    <DefaultLanguage>en</DefaultLanguage>
     <LanguageTargets>$(MSBuildExtensionsPath)\Microsoft\WindowsXaml\v$(VisualStudioVersion)\Microsoft.Windows.UI.Xaml.CSharp.targets</LanguageTargets>
   </PropertyGroup>
 

Frameworks/MQTTnet.NetStandard/MQTTnet.Netstandard.csproj

@@ -15,8 +15,7 @@
     <Description />
     <Authors />
     <PackageId />
-    <SignAssembly>true</SignAssembly>
+    <SignAssembly>false</SignAssembly>
-    <AssemblyOriginatorKeyFile>codeSigningKey.pfx</AssemblyOriginatorKeyFile>
     <DelaySign>false</DelaySign>
   </PropertyGroup>
 
@@ -29,6 +28,7 @@
     <TargetFrameworkIdentifier>.NETCore</TargetFrameworkIdentifier>
     <TargetFrameworkVersion>v5.0</TargetFrameworkVersion>
     <DefineConstants>$(DefineConstants);WINDOWS_UWP</DefineConstants>
+    <DefaultLanguage>en</DefaultLanguage>
     <LanguageTargets>$(MSBuildExtensionsPath)\Microsoft\WindowsXaml\v$(VisualStudioVersion)\Microsoft.Windows.UI.Xaml.CSharp.targets</LanguageTargets>
   </PropertyGroup>
 

Frameworks/MQTTnet.NetStandard/ManagedClient/ApplicationMessageProcessedEventArgs.cs

@@ -0,0 +1,19 @@
+using System;
+
+namespace MQTTnet.ManagedClient
+{
+    public class ApplicationMessageProcessedEventArgs : EventArgs
+    {
+        public ApplicationMessageProcessedEventArgs(MqttApplicationMessage applicationMessage, Exception exception)
+        {
+            ApplicationMessage = applicationMessage ?? throw new ArgumentNullException(nameof(applicationMessage));
+            Exception = exception;
+        }
+
+        public MqttApplicationMessage ApplicationMessage { get; }
+        public Exception Exception { get; }
+
+        public bool HasFailed => Exception != null;
+        public bool HasSucceeded => Exception == null;
+    }
+}

Frameworks/MQTTnet.NetStandard/ManagedClient/IManagedMqttClient.cs

@@ -12,6 +12,8 @@ namespace MQTTnet.ManagedClient
         event EventHandler<MqttClientConnectedEventArgs> Connected;
         event EventHandler<MqttClientDisconnectedEventArgs> Disconnected;
 
+        event EventHandler<ApplicationMessageProcessedEventArgs> ApplicationMessageProcessed;
+
         Task StartAsync(IManagedMqttClientOptions options);
         Task StopAsync();
 

Frameworks/MQTTnet.NetStandard/ManagedClient/ManagedMqttClient.cs

@@ -16,6 +16,7 @@ namespace MQTTnet.ManagedClient
         private readonly BlockingCollection<MqttApplicationMessage> _messageQueue = new BlockingCollection<MqttApplicationMessage>();
         private readonly Dictionary<string, MqttQualityOfServiceLevel> _subscriptions = new Dictionary<string, MqttQualityOfServiceLevel>();
         private readonly SemaphoreSlim _subscriptionsSemaphore = new SemaphoreSlim(1, 1);
+        private readonly List<string> _unsubscriptions = new List<string>();
 
         private readonly IMqttClient _mqttClient;
         private readonly IMqttNetLogger _logger;
@@ -27,7 +28,7 @@ namespace MQTTnet.ManagedClient
         private IManagedMqttClientOptions _options;
 
         private bool _subscriptionsNotPushed;
-        
+
         public ManagedMqttClient(IMqttClient mqttClient, IMqttNetLogger logger)
         {
             _logger = logger ?? throw new ArgumentNullException(nameof(logger));
@@ -43,6 +44,7 @@ namespace MQTTnet.ManagedClient
         public event EventHandler<MqttClientConnectedEventArgs> Connected;
         public event EventHandler<MqttClientDisconnectedEventArgs> Disconnected;
         public event EventHandler<MqttApplicationMessageReceivedEventArgs> ApplicationMessageReceived;
+        public event EventHandler<ApplicationMessageProcessedEventArgs> ApplicationMessageProcessed;
 
         public async Task StartAsync(IManagedMqttClientOptions options)
         {
@@ -57,7 +59,7 @@ namespace MQTTnet.ManagedClient
             if (_connectionCancellationToken != null) throw new InvalidOperationException("The managed client is already started.");
 
             _options = options;
-            
+
             if (_options.Storage != null)
             {
                 _storageManager = new ManagedMqttClientStorageManager(_options.Storage);
@@ -65,9 +67,9 @@ namespace MQTTnet.ManagedClient
             }
 
             _connectionCancellationToken = new CancellationTokenSource();
-            
+
 #pragma warning disable CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
-            Task.Run(async () => await MaintainConnectionAsync(_connectionCancellationToken.Token), _connectionCancellationToken.Token).ConfigureAwait(false);
+            Task.Run(async () => await MaintainConnectionAsync(_connectionCancellationToken.Token).ConfigureAwait(false), _connectionCancellationToken.Token).ConfigureAwait(false);
 #pragma warning restore CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
 
             _logger.Info<ManagedMqttClient>("Started");
@@ -85,7 +87,7 @@ namespace MQTTnet.ManagedClient
 
             return Task.FromResult(0);
         }
-        
+
         public async Task PublishAsync(IEnumerable<MqttApplicationMessage> applicationMessages)
         {
             if (applicationMessages == null) throw new ArgumentNullException(nameof(applicationMessages));
@@ -96,7 +98,7 @@ namespace MQTTnet.ManagedClient
                 {
                     await _storageManager.AddAsync(applicationMessage).ConfigureAwait(false);
                 }
-                
+
                 _messageQueue.Add(applicationMessage);
             }
         }
@@ -129,6 +131,7 @@ namespace MQTTnet.ManagedClient
                 {
                     if (_subscriptions.Remove(topic))
                     {
+                        _unsubscriptions.Add(topic);
                         _subscriptionsNotPushed = true;
                     }
                 }
@@ -153,7 +156,7 @@ namespace MQTTnet.ManagedClient
             {
                 while (!cancellationToken.IsCancellationRequested)
                 {
-                    await TryMaintainConnectionAsync(cancellationToken);
+                    await TryMaintainConnectionAsync(cancellationToken).ConfigureAwait(false);
                 }
             }
             catch (OperationCanceledException)
@@ -184,11 +187,11 @@ namespace MQTTnet.ManagedClient
 
                 if (connectionState == ReconnectionResult.Reconnected || _subscriptionsNotPushed)
                 {
-                    await PushSubscriptionsAsync().ConfigureAwait(false);
+                    await SynchronizeSubscriptionsAsync().ConfigureAwait(false);
 
                     StartPublishing();
 
-                    
+
                     return;
                 }
 
@@ -209,7 +212,7 @@ namespace MQTTnet.ManagedClient
                 _logger.Error<ManagedMqttClient>(exception, "Unhandled exception while maintaining connection.");
             }
         }
-        
+
         private async Task PublishQueuedMessagesAsync(CancellationToken cancellationToken)
         {
             try
@@ -227,7 +230,7 @@ namespace MQTTnet.ManagedClient
                         continue;
                     }
 
-                    await TryPublishQueuedMessageAsync(message).ConfigureAwait(false);                 
+                    await TryPublishQueuedMessageAsync(message).ConfigureAwait(false);
                 }
             }
             catch (OperationCanceledException)
@@ -245,6 +248,7 @@ namespace MQTTnet.ManagedClient
 
         private async Task TryPublishQueuedMessageAsync(MqttApplicationMessage message)
         {
+            Exception transmitException = null;
             try
             {
                 await _mqttClient.PublishAsync(message).ConfigureAwait(false);
@@ -256,6 +260,8 @@ namespace MQTTnet.ManagedClient
             }
             catch (MqttCommunicationException exception)
             {
+                transmitException = exception;
+
                 _logger.Warning<ManagedMqttClient>(exception, "Publishing application message failed.");
 
                 if (message.QualityOfServiceLevel > MqttQualityOfServiceLevel.AtMostOnce)
@@ -265,27 +271,38 @@ namespace MQTTnet.ManagedClient
             }
             catch (Exception exception)
             {
+                transmitException = exception;
                 _logger.Error<ManagedMqttClient>(exception, "Unhandled exception while publishing queued application message.");
             }
+            finally
+            {
+                ApplicationMessageProcessed?.Invoke(this, new ApplicationMessageProcessedEventArgs(message, transmitException));
+            }
         }
 
-        private async Task PushSubscriptionsAsync()
+        private async Task SynchronizeSubscriptionsAsync()
         {
             _logger.Info<ManagedMqttClient>(nameof(ManagedMqttClient), "Synchronizing subscriptions");
 
             List<TopicFilter> subscriptions;
+            List<string> unsubscriptions;
+
             await _subscriptionsSemaphore.WaitAsync().ConfigureAwait(false);
             try
             {
                 subscriptions = _subscriptions.Select(i => new TopicFilter(i.Key, i.Value)).ToList();
+
+                unsubscriptions = new List<string>(_unsubscriptions);
+                _unsubscriptions.Clear();
+
                 _subscriptionsNotPushed = false;
             }
             finally
             {
                 _subscriptionsSemaphore.Release();
             }
-
+            
-            if (!subscriptions.Any())
+            if (!subscriptions.Any() && !unsubscriptions.Any())
             {
                 return;
             }
@@ -293,6 +310,7 @@ namespace MQTTnet.ManagedClient
             try
             {
                 await _mqttClient.SubscribeAsync(subscriptions).ConfigureAwait(false);
+                await _mqttClient.UnsubscribeAsync(unsubscriptions).ConfigureAwait(false);
             }
             catch (Exception exception)
             {

Frameworks/MQTTnet.NetStandard/Server/MqttClientSession.cs

@@ -145,16 +145,16 @@ namespace MQTTnet.Server
             PendingMessagesQueue.Enqueue(publishPacket);
         }
 
-        public Task SubscribeAsync(IList<TopicFilter> topicFilters)
+        public async Task SubscribeAsync(IList<TopicFilter> topicFilters)
         {
             if (topicFilters == null) throw new ArgumentNullException(nameof(topicFilters));
 
-            var response = SubscriptionsManager.SubscribeAsync(new MqttSubscribePacket
+            await SubscriptionsManager.SubscribeAsync(new MqttSubscribePacket
             {
                 TopicFilters = topicFilters
-            });
+            }).ConfigureAwait(false);
 
-            return response;
+            await EnqueueSubscribedRetainedMessagesAsync(topicFilters).ConfigureAwait(false);
         }
 
         public Task UnsubscribeAsync(IList<string> topicFilters)
@@ -270,7 +270,7 @@ namespace MQTTnet.Server
                 await StopAsync().ConfigureAwait(false);
             }
 
-            await EnqueueSubscribedRetainedMessagesAsync(subscribePacket).ConfigureAwait(false);
+            await EnqueueSubscribedRetainedMessagesAsync(subscribePacket.TopicFilters).ConfigureAwait(false);
         }
 
         private async Task HandleIncomingUnsubscribePacketAsync(IMqttChannelAdapter adapter, MqttUnsubscribePacket unsubscribePacket, CancellationToken cancellationToken)
@@ -279,12 +279,12 @@ namespace MQTTnet.Server
             await adapter.SendPacketsAsync(_options.DefaultCommunicationTimeout, cancellationToken, unsubscribeResult);
         }
 
-        private async Task EnqueueSubscribedRetainedMessagesAsync(MqttSubscribePacket subscribePacket)
+        private async Task EnqueueSubscribedRetainedMessagesAsync(ICollection<TopicFilter> topicFilters)
         {
-            var retainedMessages = await _retainedMessagesManager.GetSubscribedMessagesAsync(subscribePacket);
+            var retainedMessages = await _retainedMessagesManager.GetSubscribedMessagesAsync(topicFilters);
-            foreach (var publishPacket in retainedMessages)
+            foreach (var applicationMessage in retainedMessages)
             {
-                await EnqueueApplicationMessageAsync(publishPacket);
+                await EnqueueApplicationMessageAsync(applicationMessage).ConfigureAwait(false);
             }
         }
 

Frameworks/MQTTnet.NetStandard/Server/MqttClientSessionsManager.cs

@@ -220,7 +220,8 @@ namespace MQTTnet.Server
 
         private MqttApplicationMessage InterceptApplicationMessage(MqttClientSession senderClientSession, MqttApplicationMessage applicationMessage)
         {
-            if (_options.ApplicationMessageInterceptor == null)
+            var interceptor = _options.ApplicationMessageInterceptor;
+            if (interceptor == null)
             {
                 return applicationMessage;
             }
@@ -229,7 +230,7 @@ namespace MQTTnet.Server
                 senderClientSession.ClientId,
                 applicationMessage);
 
-            _options.ApplicationMessageInterceptor(interceptorContext);
+            interceptor(interceptorContext);
             return interceptorContext.ApplicationMessage;
         }
 

Frameworks/MQTTnet.NetStandard/Server/MqttRetainedMessagesManager.cs

@@ -4,7 +4,6 @@ using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using MQTTnet.Diagnostics;
-using MQTTnet.Packets;
 
 namespace MQTTnet.Server
 {
@@ -68,7 +67,7 @@ namespace MQTTnet.Server
             }
         }
 
-        public async Task<List<MqttApplicationMessage>> GetSubscribedMessagesAsync(MqttSubscribePacket subscribePacket)
+        public async Task<List<MqttApplicationMessage>> GetSubscribedMessagesAsync(ICollection<TopicFilter> topicFilters)
         {
             var retainedMessages = new List<MqttApplicationMessage>();
 
@@ -77,13 +76,8 @@ namespace MQTTnet.Server
             {
                 foreach (var retainedMessage in _retainedMessages.Values)
                 {
-                    foreach (var topicFilter in subscribePacket.TopicFilters)
+                    foreach (var topicFilter in topicFilters)
                     {
-                        if (retainedMessage.QualityOfServiceLevel < topicFilter.QualityOfServiceLevel)
-                        {
-                            continue;
-                        }
-
                         if (!MqttTopicFilterComparer.IsMatch(retainedMessage.Topic, topicFilter.Topic))
                         {
                             continue;

Frameworks/MQTTnet.Netstandard/MQTTnet.NetStandard.csproj

@@ -15,8 +15,7 @@
     <Description />
     <Authors />
     <PackageId />
-    <SignAssembly>true</SignAssembly>
+    <SignAssembly>false</SignAssembly>
-    <AssemblyOriginatorKeyFile>codeSigningKey.pfx</AssemblyOriginatorKeyFile>
     <DelaySign>false</DelaySign>
   </PropertyGroup>
 
@@ -29,6 +28,7 @@
     <TargetFrameworkIdentifier>.NETCore</TargetFrameworkIdentifier>
     <TargetFrameworkVersion>v5.0</TargetFrameworkVersion>
     <DefineConstants>$(DefineConstants);WINDOWS_UWP</DefineConstants>
+    <DefaultLanguage>en</DefaultLanguage>
     <LanguageTargets>$(MSBuildExtensionsPath)\Microsoft\WindowsXaml\v$(VisualStudioVersion)\Microsoft.Windows.UI.Xaml.CSharp.targets</LanguageTargets>
   </PropertyGroup>