SpeechEventInfo Constructor (Int16, Int16, Int32, IntPtr)


The .NET API Reference documentation has a new home. Visit the .NET API Browser on docs.microsoft.com to see the new experience.

Constucts an appropriate SpeechEventInfo.

Namespace:   System.Speech.Synthesis.TtsEngine
Assembly:  System.Speech (in System.Speech.dll)

public SpeechEventInfo(
	short eventId,
	short parameterType,
	int param1,
	IntPtr param2


Type: System.Int16

An instance of TtsEventId indicating the sort of Speech platform event the SpeechEventInfo object is to handle.

Type: System.Int16

An instance of EventParameterType indicating how the System.IntPtr reference of param2 is to be interpreted, and, by implication, the use of param1.

Type: System.Int32

An integer value to be passed to the Speech platform when the event requested by the instance of SpeechEventInfo to be constructed is generated.

The exact meaning of this integer is implicitly determined by the value of parameterType.

Type: System.IntPtr

A System.IntPtr instance referencing an object. to be passed to the Speech platform when the event requested by the instance of SpeechEventInfo to be constructed is generated.

The type which must be referenced is explicitly defined by the value parameterType. The value System.IntPtr.Zero.

Permitted values used for parameterType, param1, and param2 and their meaning is dictated by the type of event being requested, as specified by the member of TtsEventId used for eventId.

For detailed information on appropriate values for parameterType, param1, and param2, see documentation for EventId

The type of the events which can be handled by the Speech platform infrastructure can be obtained through the EventInterest property on the synthesizer engine site implementation of ITtsEngineSite.

The example below is part of a custom speech synthesis implementation inheriting from TtsEngineSsml, and using the use of TextFragment, SpeechEventInfo, FragmentState, and TtsEventId

The implementation of Speak

  1. Receives an array of TextFragment instances and creates a new array of TextFragment instances to be passed to the Speak method on an underlying synthesis engine.

  2. If the TtsEngineAction enumeration value by found from the Action property on the FragmentState returned by the State property of each TextFragment instance is Speak, the implementation

    • Translates Americanism to Britishisms in the text to be spoken.

    • If the EventInterest property on the ITtsEngineSite interfaces provided to the implementation support the WordBoundary event type, a SpeechEventInfo instance is used to create an event to drive a synthesizer progress meter is created.

  3. A speech rendering engine is then called with the modified TextFragment array.

private const int WordBoundaryFlag = 1 << (int)TtsEventId.WordBoundary;
private readonly char[] spaces = new char[] { ' ', '\t', '\r', '\n' };
internal struct UsVsUk
  internal string UK;
  internal string US;

override public void Speak (TextFragment [] frags, IntPtr wfx, ITtsEngineSite site)
  TextFragment [] newFrags=new TextFragment[frags.Length];

  for (int i=0;i<frags.Length;i++){
    newFrags[i].TextToSpeak = frags[i].TextToSpeak.Substring(frags[i].TextOffset,
    newFrags[i].TextLength = newFrags[i].TextToSpeak.Length;
    newFrags[i].TextOffset = 0;
    if (newFrags[i].State.Action == TtsEngineAction.Speak) {
      //Us to UK conversion
      foreach (UsVsUk term in TransList) {
      newFrags[i].TextToSpeak.Replace(term.US, term.UK);
      //Generate progress meter events if supported
      if ((site.EventInterest & WordBoundaryFlag) != 0) {
      string[] subs = newFrags[i].TextToSpeak.Split(spaces);

      foreach (string s in subs) {
        int offset = newFrags[i].TextOffset;
        SpeechEventInfo spEvent = new SpeechEventInfo((Int16)TtsEventId.WordBoundary, 
                 s.Length, new IntPtr(offset));
        offset += s.Length;
        if (s.Trim().Length > 0) {
          SpeechEventInfo[] events = new SpeechEventInfo[1];
          events[0] = spEvent;
          site.AddEvents(events, 1);

  _baseSynthesize.Speak(newFrags, wfx, site);


.NET Framework
Available since 3.0
Return to top