Grammar Constructor (SrgsDocument, String, Uri)
Constructs a new instance of Grammar from an instance of SrgsDocument the name of a particular rule to be the grammar’s root rule, and a base URI for relative references.
Namespace: Microsoft.Speech.Recognition
Assembly: Microsoft.Speech (in microsoft.speech.dll)
Syntax
'Declaration
Parameters
- srgsDocument
An instance of SrgsDocument to a file containing a rules and a grammar to be used to construct the Grammar object.
ruleName
Name of a grammar rule used as the entry point or root of the Grammar object to be created.This parameter may be null.
baseUri
System.Uri object defining base path that any relative rule references, for example to other grammars, within the grammar are resolved against.This parameter may be null.
Exceptions
| Exception type | Condition |
|---|---|
| ArgumentException | Generated for invalid srgsDocuments,ruleName, or baseUri values. Generated if the SrgsDocument specified by srgsDocument does not contain the rule ruleName, or has a relative rule reference not resolvable by the default base System.Uri rule for grammars or the Uri supplied by baseUri . |
Remarks
The srgsDocument argument
Must never be null.
Must contain the rule specified by ruleName, if ruleName is not null, and a root rule if ruleName is null.
The ruleName argument:
May be null or System.String.Empty.
If ruleName is not null and the rule specified is not found in the grammar being loaded, an exception is generated.
If ruleName is null, the grammar contained in the file specified by must specify a root rule. If there is not root rule in the grammar being loaded an exception is generated.
(For more information on root rules, see the discussion of the Root property on the Microsoft.Speech.Recognition.SrgsGrammar.SrgsDocument class.)
The baseUri argument:
The value of baseUri should be an absolute URI, and can be a path or a file.
If the value of baseUri is a path, be sure and append a trailing slash.
The URI provided by baseUri is not validated when the Grammar object is constructed.
Instead, if the URI is invalid or any relative references inaccessible, on grammar load, a recognition engine (instances of SpeechRecognizer or SpeechRecognitionEngine) generates and exception.
Recognition engine handle references within a Grammar being loaded by:
Resolving all references with absolute URIs.
Attempting resolution within the XML of Grammar being loaded.
Using any paths indicated in the instance of srgsDocument used to create the Grammar to resolve the reference. If the srgsDocument has been created from a file, this typically includes the directory where that file was located.
Trying to resolve the reference with the value ofbaseUri if it is non-null.
No parameters are supplied to this constructor, therefore the loaded rule should either have no initialization handler defined, or the initialization handler should require no arguments.
Example
The following try/catch block attempts to create a new Grammar from an instance of SrgsDocument (srgsDoc).
The SrgsDocument instance must:
Contain a rule named
"MapLookup"Have all references to other rules and grammars accessible in the file http://mapLookup.com/MapUtils.xml
"Have no initialization handler, or a handler that takes not arguments.
XML defining SRGS content that would satisfy these conditions can be found following the source to this try/catch block.
try {
Grammar grammar = new Grammar(srgsDoc,
@"MapLookup",
new Uri("http://mapLookup.com/MapUtils.xml"));
grammar.Enabled = true;
_recognizer.LoadGrammar(grammar);
} catch (System.ArgumentException exp) {
MessageBox.Show(String.Format("Invalid constructor arguments:\n{0}\n", exp.Message));
} catch (Exception exp) {
// Catch all other exceptions
MessageBox.Show(String.Format("Failed to load {0}.\nError Message:\n{1}",
filename, exp.Message));
}
A sample MapLookup.xml:
<grammar xml:lang="en-us" version="1.0"
xmlns="http://www.w3.org/2001/06/grammar" tag-format="properties-ms/1.0"
xmlns:sapi="http://schemas.microsoft.com/Speech/2002/06/SRGSExtensions"
sapi:debug="True" root="MapLookup">
<rule id="MapLookup" scope="public" sapi:onParse="OnParseMapLookup" sapi:onInit="OnInit" >
bis
</rule>
<sapi:script sapi:rule="MapLookup">
<![CDATA[
public object OnParseMapLookup(SemanticValue result, RecognizedWordUnit[] words) {
Console.WriteLine("OnParse MapLookup: " + _value);
return _value;
}
public SrgsRule[] OnInit(string state_region, string city, string country) {
Console.WriteLine(String.Format("Initializer using three arguments: {0},{1},{2}\n",
state_region, city, country));
_state_region = state_region;
_city = city;
_country = country;
return null;
}
public SrgsRule[] OnInit( string city, string state_region)
{
Console.WriteLine (String.Format("Initializer using two arguments: {0},{1}\n",
city,state_region));
_state_region = state_region;
_city=city;
_country="United States";
return null;
}
public SrgsRule[] OnInit(string country) {
Console.WriteLine(String.Format("Initializer using one argument: {0}\n",
country));
_state_region = null;
_city = null;
_country = country;
return null;
}
public SrgsRule[] OnInit() {
Console.WriteLine(String.Format("Initializer using no arguments\n"));
_state_region = null;
_city = null;
_country = "United States";
return null;
}
private string _state_region;
private string _city;
private string _state_region1;
private string _city1;
private string _value;
private string _country;
]]>
</sapi:script>
</grammar>
Platforms
Development Platforms
Windows XP Professional with Service Pack 2 (SP2), Windows Server 2003, Windows Vista Ultimate Edition, Windows Vista Business Edition, Windows Vista Enterprise Edition
Target Platforms
See Also
Reference
Grammar Class
Grammar Members
Microsoft.Speech.Recognition Namespace
Microsoft.Speech.Recognition.SrgsGrammar
SrgsDocument
SpeechRecognizer
SpeechRecognitionEngine
Grammar Constructor