Integrate with a client application using Speech SDK


Custom Commands will be retired on April 30th 2026. As of October 30th 2023 you can't create new Custom Commands applications in Speech Studio. Related to this change, LUIS will be retired on October 1st 2025. As of April 1st 2023 you can't create new LUIS resources.

In this article, you learn how to make requests to a published Custom Commands application from the Speech SDK running in an UWP application. In order to establish a connection to the Custom Commands application, you need:

  • Publish a Custom Commands application and get an application identifier (App ID)
  • Create a Universal Windows Platform (UWP) client app using the Speech SDK to allow you to talk to your Custom Commands application


A Custom Commands application is required to complete this article. Try a quickstart to create a custom commands application:

You also need:

Step 1: Publish Custom Commands application

  1. Open your previously created Custom Commands application.

  2. Go to Settings, select LUIS resource.

  3. If Prediction resource isn't assigned, select a query prediction key or create a new one.

    Query prediction key is always required before publishing an application. For more information about LUIS resources, reference Create LUIS Resource

  4. Go back to editing Commands, Select Publish.

    Publish application

  5. Copy the App ID from the "publish" notification for later use.

  6. Copy the Speech Resource Key for later use.

Step 2: Create a Visual Studio project

Create a Visual Studio project for UWP development and install the Speech SDK.

Step 3: Add sample code

In this step, we add the XAML code that defines the user interface of the application, and add the C# code-behind implementation.

XAML code

Create the application's user interface by adding the XAML code.

  1. In Solution Explorer, open MainPage.xaml

  2. In the designer's XAML view, replace the entire contents with the following code snippet:

        Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
            <StackPanel Orientation="Vertical" HorizontalAlignment="Center"
                        Margin="20,50,0,0" VerticalAlignment="Center" Width="800">
                <Button x:Name="EnableMicrophoneButton" Content="Enable Microphone"
                        Margin="0,10,10,0" Click="EnableMicrophone_ButtonClicked"
                <Button x:Name="ListenButton" Content="Talk"
                        Margin="0,10,10,0" Click="ListenButton_ButtonClicked"
                <StackPanel x:Name="StatusPanel" Orientation="Vertical"
                    <TextBlock x:Name="StatusLabel" Margin="0,10,10,0"
                               TextWrapping="Wrap" Text="Status:" FontSize="20"/>
                    <Border x:Name="StatusBorder" Margin="0,0,0,0">
                        <ScrollViewer VerticalScrollMode="Auto"
                                      VerticalScrollBarVisibility="Auto" MaxHeight="200">
                            <!-- Use LiveSetting to enable screen readers to announce
                                 the status update. -->
                                x:Name="StatusBlock" FontWeight="Bold"
                                MaxWidth="{Binding ElementName=Splitter, Path=ActualWidth}"
                                Margin="10,10,10,20" TextWrapping="Wrap"  />
            <MediaElement x:Name="mediaElement"/>

The Design view is updated to show the application's user interface.

C# code-behind source

Add the code-behind source so that the application works as expected. The code-behind source includes:

  • Required using statements for the Speech and Speech.Dialog namespaces.
  • A simple implementation to ensure microphone access, wired to a button handler.
  • Basic UI helpers to present messages and errors in the application.
  • A landing point for the initialization code path.
  • A helper to play back text to speech (without streaming support).
  • An empty button handler to start listening.

Add the code-behind source as follows:

  1. In Solution Explorer, open the code-behind source file MainPage.xaml.cs (grouped under MainPage.xaml)

  2. Replace the file's contents with the following code:

    using Microsoft.CognitiveServices.Speech;
    using Microsoft.CognitiveServices.Speech.Audio;
    using Microsoft.CognitiveServices.Speech.Dialog;
    using System;
    using System.IO;
    using System.Text;
    using Windows.UI.Xaml;
    using Windows.UI.Xaml.Controls;
    using Windows.UI.Xaml.Media;
    namespace helloworld
        public sealed partial class MainPage : Page
            private DialogServiceConnector connector;
            private enum NotifyType
            public MainPage()
            private async void EnableMicrophone_ButtonClicked(
                object sender, RoutedEventArgs e)
                bool isMicAvailable = true;
                    var mediaCapture = new Windows.Media.Capture.MediaCapture();
                    var settings =
                        new Windows.Media.Capture.MediaCaptureInitializationSettings();
                    settings.StreamingCaptureMode =
                    await mediaCapture.InitializeAsync(settings);
                catch (Exception)
                    isMicAvailable = false;
                if (!isMicAvailable)
                    await Windows.System.Launcher.LaunchUriAsync(
                        new Uri("ms-settings:privacy-microphone"));
                    NotifyUser("Microphone was enabled", NotifyType.StatusMessage);
            private void NotifyUser(
                string strMessage, NotifyType type = NotifyType.StatusMessage)
                // If called from the UI thread, then update immediately.
                // Otherwise, schedule a task on the UI thread to perform the update.
                if (Dispatcher.HasThreadAccess)
                    UpdateStatus(strMessage, type);
                    var task = Dispatcher.RunAsync(
                        () => UpdateStatus(strMessage, type));
            private void UpdateStatus(string strMessage, NotifyType type)
                switch (type)
                    case NotifyType.StatusMessage:
                        StatusBorder.Background = new SolidColorBrush(
                    case NotifyType.ErrorMessage:
                        StatusBorder.Background = new SolidColorBrush(
                StatusBlock.Text += string.IsNullOrEmpty(StatusBlock.Text)
                    ? strMessage : "\n" + strMessage;
                if (!string.IsNullOrEmpty(StatusBlock.Text))
                    StatusBorder.Visibility = Visibility.Visible;
                    StatusPanel.Visibility = Visibility.Visible;
                    StatusBorder.Visibility = Visibility.Collapsed;
                    StatusPanel.Visibility = Visibility.Collapsed;
                // Raise an event if necessary to enable a screen reader
                // to announce the status update.
                var peer = Windows.UI.Xaml.Automation.Peers.FrameworkElementAutomationPeer.FromElement(StatusBlock);
                if (peer != null)
            // Waits for and accumulates all audio associated with a given
            // PullAudioOutputStream and then plays it to the MediaElement. Long spoken
            // audio will create extra latency and a streaming playback solution
            // (that plays audio while it continues to be received) should be used --
            // see the samples for examples of this.
            private void SynchronouslyPlayActivityAudio(
                PullAudioOutputStream activityAudio)
                var playbackStreamWithHeader = new MemoryStream();
                playbackStreamWithHeader.Write(Encoding.ASCII.GetBytes("RIFF"), 0, 4); // ChunkID
                playbackStreamWithHeader.Write(BitConverter.GetBytes(UInt32.MaxValue), 0, 4); // ChunkSize: max
                playbackStreamWithHeader.Write(Encoding.ASCII.GetBytes("WAVE"), 0, 4); // Format
                playbackStreamWithHeader.Write(Encoding.ASCII.GetBytes("fmt "), 0, 4); // Subchunk1ID
                playbackStreamWithHeader.Write(BitConverter.GetBytes(16), 0, 4); // Subchunk1Size: PCM
                playbackStreamWithHeader.Write(BitConverter.GetBytes(1), 0, 2); // AudioFormat: PCM
                playbackStreamWithHeader.Write(BitConverter.GetBytes(1), 0, 2); // NumChannels: mono
                playbackStreamWithHeader.Write(BitConverter.GetBytes(16000), 0, 4); // SampleRate: 16kHz
                playbackStreamWithHeader.Write(BitConverter.GetBytes(32000), 0, 4); // ByteRate
                playbackStreamWithHeader.Write(BitConverter.GetBytes(2), 0, 2); // BlockAlign
                playbackStreamWithHeader.Write(BitConverter.GetBytes(16), 0, 2); // BitsPerSample: 16-bit
                playbackStreamWithHeader.Write(Encoding.ASCII.GetBytes("data"), 0, 4); // Subchunk2ID
                playbackStreamWithHeader.Write(BitConverter.GetBytes(UInt32.MaxValue), 0, 4); // Subchunk2Size
                byte[] pullBuffer = new byte[2056];
                uint lastRead = 0;
                    lastRead = activityAudio.Read(pullBuffer);
                    playbackStreamWithHeader.Write(pullBuffer, 0, (int)lastRead);
                while (lastRead == pullBuffer.Length);
                var task = Dispatcher.RunAsync(
                    Windows.UI.Core.CoreDispatcherPriority.Normal, () =>
                        playbackStreamWithHeader.AsRandomAccessStream(), "audio/wav");
            private void InitializeDialogServiceConnector()
                // New code will go here
            private async void ListenButton_ButtonClicked(
                object sender, RoutedEventArgs e)
                // New code will go here


    If you see error: "The type 'Object' is defined in an assembly that is not referenced"

    1. Right-client your solution.
    2. Choose Manage NuGet Packages for Solution, Select Updates
    3. If you see Microsoft.NETCore.UniversalWindowsPlatform in the update list, Update Microsoft.NETCore.UniversalWindowsPlatform to newest version
  3. Add the following code to the method body of InitializeDialogServiceConnector

    // This code creates the `DialogServiceConnector` with your resource information.
    // create a DialogServiceConfig by providing a Custom Commands application id and Speech resource key
    // The RecoLanguage property is optional (default en-US); note that only en-US is supported in Preview
    const string speechCommandsApplicationId = "YourApplicationId"; // Your application id
    const string speechSubscriptionKey = "YourSpeechSubscriptionKey"; // Your Speech resource key
    const string region = "YourServiceRegion"; // The Speech resource region. 
    var speechCommandsConfig = CustomCommandsConfig.FromSubscription(speechCommandsApplicationId, speechSubscriptionKey, region);
    speechCommandsConfig.SetProperty(PropertyId.SpeechServiceConnection_RecoLanguage, "en-us");
    connector = new DialogServiceConnector(speechCommandsConfig);
  4. Replace the strings YourApplicationId, YourSpeechSubscriptionKey, and YourServiceRegion with your own values for your app, speech key, and region

  5. Append the following code snippet to the end of the method body of InitializeDialogServiceConnector

    // This code sets up handlers for events relied on by `DialogServiceConnector` to communicate its activities,
    // speech recognition results, and other information.
    // ActivityReceived is the main way your client will receive messages, audio, and events
    connector.ActivityReceived += (sender, activityReceivedEventArgs) =>
            $"Activity received, hasAudio={activityReceivedEventArgs.HasAudio} activity={activityReceivedEventArgs.Activity}");
        if (activityReceivedEventArgs.HasAudio)
    // Canceled will be signaled when a turn is aborted or experiences an error condition
    connector.Canceled += (sender, canceledEventArgs) =>
        NotifyUser($"Canceled, reason={canceledEventArgs.Reason}");
        if (canceledEventArgs.Reason == CancellationReason.Error)
                $"Error: code={canceledEventArgs.ErrorCode}, details={canceledEventArgs.ErrorDetails}");
    // Recognizing (not 'Recognized') will provide the intermediate recognized text
    // while an audio stream is being processed
    connector.Recognizing += (sender, recognitionEventArgs) =>
        NotifyUser($"Recognizing! in-progress text={recognitionEventArgs.Result.Text}");
    // Recognized (not 'Recognizing') will provide the final recognized text
    // once audio capture is completed
    connector.Recognized += (sender, recognitionEventArgs) =>
        NotifyUser($"Final speech to text result: '{recognitionEventArgs.Result.Text}'");
    // SessionStarted will notify when audio begins flowing to the service for a turn
    connector.SessionStarted += (sender, sessionEventArgs) =>
        NotifyUser($"Now Listening! Session started, id={sessionEventArgs.SessionId}");
    // SessionStopped will notify when a turn is complete and
    // it's safe to begin listening again
    connector.SessionStopped += (sender, sessionEventArgs) =>
        NotifyUser($"Listening complete. Session ended, id={sessionEventArgs.SessionId}");
  6. Add the following code snippet to the body of the ListenButton_ButtonClicked method in the MainPage class

    // This code sets up `DialogServiceConnector` to listen, since you already established the configuration and
    // registered the event handlers.
    if (connector == null)
        // Optional step to speed up first interaction: if not called,
        // connection happens automatically on first use
        var connectTask = connector.ConnectAsync();
        // Start sending audio
        await connector.ListenOnceAsync();
    catch (Exception ex)
        NotifyUser($"Exception: {ex.ToString()}", NotifyType.ErrorMessage);
  7. From the menu bar, choose File > Save All to save your changes

Try it out

  1. From the menu bar, choose Build > Build Solution to build the application. The code should compile without errors.

  2. Choose Debug > Start Debugging (or press F5) to start the application. The helloworld window appears.

    Sample UWP virtual assistant application in C# - quickstart

  3. Select Enable Microphone. If the access permission request pops up, select Yes.

    Microphone access permission request

  4. Select Talk, and speak an English phrase or sentence into your device's microphone. Your speech is transmitted to the Direct Line Speech channel and transcribed to text, which appears in the window.

Next steps