SemanticResultKey Class
Attaches key string to SemanticResultValue values to define the SemanticValue objects created in Grammar using GrammarBuilder instances
Assembly: System.Speech (in System.Speech.dll)
The basic unit of semantic expression under Speech platform is the SemanticValue which is a key value pair.
The SemanticResultKey object tags SemanticResultValue instances contained in GrammarBuilder objects and strings so that the values may readily be accessed from SemanticValue instances on recognition.
Use of SemanticResultValue and SemanticResultKey objects, in conjunction with GrammarBuilder and Choices is the easiest way to design a semantic structure for a Grammar. Semantic information for a phrase is accessed by obtaining and instance of SemanticValue, through the Semantics property on RecognizedPhrase.
The example below creates a Grammar to recognize password input of the form "My password is …", where the actual input is matched with a wildcard.
The wildcard is tagged with a semantic key, and the SpeechRecognized handler check for the presence of this tag to verify that a password input has occurred.
private void pwdGrammar() {
GrammarBuilder pwdBuilder = new GrammarBuilder("My Password is");
GrammarBuilder wildcardBuilder = new GrammarBuilder();
wildcardBuilder.AppendWildcard();
SemanticResultKey wildcardKey= new SemanticResultKey("Password", wildcardBuilder);
pwdBuilder+=wildcardKey;
Grammar grammar = new Grammar(pwdBuilder);
grammar.Name = "Password input";
grammar.SpeechRecognized +=
delegate(object sender, SpeechRecognizedEventArgs eventArgs) {
SemanticValue semantics = eventArgs.Result.Semantics;
RecognitionResult result=eventArgs.Result;
if (!semantics.ContainsKey("Password")) {
SpeechUI.SendTextFeedback(eventArgs.Result,
"No Password Provided", false);
} else {
RecognizedAudio pwdAudio = result.GetAudioForWordRange(result.Words[3],
result.Words[result.Words.Count - 1]);
MemoryStream pwdMemoryStream = new MemoryStream();
pwdAudio.WriteToAudioStream(pwdMemoryStream);
if (!IsValidPwd(pwdMemoryStream)) {
string badPwd = System.IO.Path.GetTempPath() + "BadPwd" + (new Random()).Next().ToString() + ".wav";
FileStream waveStream = new FileStream(badPwd, FileMode.Create);
pwdAudio.WriteToWaveStream(waveStream);
waveStream.Flush();
waveStream.Close();
SpeechUI.SendTextFeedback(eventArgs.Result,
"Invalid Password", false);
}
}
};
grammar.Enabled = true;
_recognizer.LoadGrammar(grammar);
UpdateGrammarTree(_grammarTreeView, _recognizer);
}
Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
