SpeechEventInfo Struct


Used to specify the type of event, and its arguments (if any) to be generated as part of the rendering of text to speech by a custom synthetic speech engine.

public value class SpeechEventInfo : IEquatable<System::Speech::Synthesis::TtsEngine::SpeechEventInfo>
public struct SpeechEventInfo : IEquatable<System.Speech.Synthesis.TtsEngine.SpeechEventInfo>
type SpeechEventInfo = struct
Public Structure SpeechEventInfo
Implements IEquatable(Of SpeechEventInfo)


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);  



A custom speech synthesis engine requests the generation of events under the Speech Platform by providing an appropriate SpeechEventInfo instance to AddEvents member of the ITtsEngineSite engine site object passed to implementations of Speak, AddLexicon, and RemoveLexicon.


SpeechEventInfo(Int16, Int16, Int32, IntPtr)

Constructs an appropriate SpeechEventInfo.



Gets and set the Speech platform event which an instance of SpeechEventInfo is used to request.


Gets and set the integer value (param1 in the constructor) to be passed to the Speech platform to generate an event the current instance of SpeechEventInfo is used to request.


Gets and set the System.IntPtr instance (param2 in the constructor) referencing the object to be passed to the Speech platform to generate an event the current instance of SpeechEventInfo is used to request.


Returns the data type of the object pointed to by the IntPtr returned by the Param2 parameter on the current SpeechEventInfo object.



Determines whether a specified object is an instance of SpeechEventInfo and equal to the current instance of SpeechEventInfo.


Determines whether a specified SpeechEventInfo object is equal to the current instance of SpeechEventInfo.


Provides a hash code for a SpeechEventInfo object.


Equality(SpeechEventInfo, SpeechEventInfo)

Determines whether two instances of SpeechEventInfo are equal.

Inequality(SpeechEventInfo, SpeechEventInfo)

Determines whether two instances of SpeechEventInfo are not equal.

Applies to