How to properly dispose of SpeechSynthesizer for async text-to-speech?

问题

I have a form and I want to allow the user to receive asynchronous text-to-speech output based on the content of a text box whenever a button is pressed. For context, this form is launched as part of an "internal" C# function within VoiceAttack, and this is a continuation of a previous question. This snippet does the job nicely:

SpeechSynthesizer synth = new SpeechSynthesizer(); // Create new SpeechSynthesizer instance

// Function for asynchronous voicing of text with text-to-speech
public void VoiceText(string text)
{
    string MyVoice = null; // Initialize string for storing requested text-to-speech voice
    string DefaultVoice = null; // Initialize string for storing default Windows text-to-speech voice
    try // Attempt the following code...
    {
        synth.SpeakAsyncCancelAll(); // Cancels all queued, asynchronous, speech synthesis operations
        synth.Volume = 100; // Set the volume level of the text-to-speech voice
        synth.Rate = -2; // Set the rate at which text is spoken by the text-to-speech engine
        MyVoice = VA.GetText(">SDTTextToSpeechVoice") ?? "Not Set"; // Retrieve phonemes for processed text or set to null
        DefaultVoice = synth.Voice.Name; // Store the current default Windows text-to-speech voice
        if (MyVoice == "Default") // Check if requested voice name is "Default"
        {
            MyVoice = DefaultVoice; // Set MyVoice to the DefaultVoice
            VA.SetText(">SDTTextToSpeechVoice", MyVoice); // Redefine VoiceAttack text variable based on redefined MyVoice
        }
        synth.SelectVoice(MyVoice); // Set the voice for this instance of text-to-speech output
    }
    catch // Handle exceptions encountered in "try"
    {
        synth.SelectVoice(DefaultVoice); // Set the voice for this instance of text-to-speech output to the Windows default voice
        string VoiceList = null; // Initialize string variable for storing available text-to-speech voice names
        foreach (InstalledVoice v in synth.GetInstalledVoices()) // Loop through all available text-to-speech voices
            VoiceList += ", " + v.VoiceInfo.Name; // Add text-to-speech voice name to storage variable
        VA.WriteToLog("Text-to-speech voice '" + MyVoice + "' not found", "yellow"); // Output info to event log
        VA.WriteToLog("Valid TTS Voices = " + VoiceList.Trim(',', ' '), "yellow"); // Output info to event log
        VA.WriteToLog("Defaulting to current Windows text-to-speech voice (" + DefaultVoice + ")", "yellow"); // Output info to event log
    }
    synth.SpeakAsync(text); // Generate text-to-speech output asynchronously
}

// Function for disposing SpeechSynthesizer object
public void SpeechDispose()
{
    synth.Dispose(); // Releases resources tied to SpeechSynthesizer object
}

SpeechDispose() is called upon form closing. I can't enclose synth in a using() statement because the voicing is asynchronous (I want the user to not be forced to wait for the voicing to finish before the button can be pressed again). Is there a better way to clean up?

来源：https://stackoverflow.com/questions/55168576/how-to-properly-dispose-of-speechsynthesizer-for-async-text-to-speech

标签

text-to-speech

sapi

speech-synthesis