Initializes a new instance of the Grammar class from a stream, specifies a root rule, and defines a base Uniform Resource Identifier (URI) to resolve relative rule references.
Namespace:
Microsoft.Speech.Recognition
Assembly:
Microsoft.Speech (in Microsoft.Speech.dll)
Syntax
| Visual Basic (Declaration) |
|---|
Public Sub New ( _ stream As Stream, _ ruleName As String, _ baseUri As Uri _ ) |
| Visual Basic (Usage) |
|---|
Dim stream As Stream Dim ruleName As String Dim baseUri As Uri Dim instance As New Grammar(stream, _ ruleName, baseUri) |
| C# |
|---|
public Grammar( Stream stream, string ruleName, Uri baseUri ) |
Parameters
- stream
- Type: System.IO..::..Stream
A stream that describes a speech recognition grammar in a supported format.
- ruleName
- Type: System..::..String
The identifier of the rule to use as the entry point of the speech recognition grammar, or nullNothingnullptrunita null reference (Nothing in Visual Basic) to use the default root rule of the grammar description.
- baseUri
- Type: System..::..Uri
The base URI to use to resolve any relative rule reference in the grammar description, or nullNothingnullptrunita null reference (Nothing in Visual Basic).
Exceptions
| Exception | Condition |
|---|---|
| ArgumentException | Thrown when stream, ruleName, or baseUri have invalid values. Thrown when the stream is connected to a grammar that does not contain the rule ruleName, or has a relative rule reference not resolvable using the baseUri. |
Remarks
The stream argument:
Can never be nullNothingnullptrunita null reference (Nothing in Visual Basic) and must be readable.
In general, the object a stream is connected to must be a grammar file that conforms to the W3C Speech Recognition Grammar Specification (SRGS) Version 1.0.
However:
If the input stream is connected to a Visual Studio Resource, the Resource can only contain grammar files in binary format with the .cfg extension.
If the input stream is connected to a DLL, that DLL must contain instances of Grammar.
The ruleName argument:
May be nullNothingnullptrunita null reference (Nothing in Visual Basic) or Empty.
If ruleName is not nullNothingnullptrunita null reference (Nothing in Visual Basic) and the rule specified is not found in the grammar being loaded, an exception is generated.
If ruleName is nullNothingnullptrunita null reference (Nothing in Visual Basic), and the grammar contained in the file specified does not declare a root rule, an exception is generated.
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 to 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 are inaccessible, the SpeechRecognitionEngine generates and exception when it loads the grammar.
The recognition engine performs the following checks on Grammar objects it is loading:
Resolves all references with absolute URIs.
Checks the XML of Grammar being loaded for correct syntax.
Resolves references with the value of baseUri if it is non-null.
Examples
The following example loads a local SRGS file (shuttle.xml) from a file stream. The file contains a relative rule reference to a rule in the cities.xml file, and specifies a base URI to use to resolve the rule reference. The content of the shuttle.xml and cities.xml files appears in the XML examples that follow the C# example.
| C# | Copy Code |
|---|---|
private static Grammar CreateGrammarFromStream3()
{
FileInfo file = new FileInfo(@".\shuttle.xml");
Uri baseUri = new Uri(@"file://c:\temp\");
Grammar citiesGrammar = new Grammar(file.OpenRead(), null, baseUri);
citiesGrammar.Name = "Stream Cities Grammar 3";
return citiesGrammar;
}
| |
| XML | Copy Code |
|---|---|
<?xml version="1.0" encoding="UTF-8" ?>
<grammar version="1.0" xml:lang="en-US"
xmlns="http://www.w3.org/2001/06/grammar"
tag-format="semantics/1.0" root="Main">
<!-- shuttle.xml:
Defines an SRGS grammar for asking about a shuttle service. This grammar
references a Cities rule that is defined in the cities.xml grammar. -->
<rule id="Main">
<item>
Can I get a shuttle in
<ruleref uri="cities.xml#Cities"/>
</item>
</rule>
</grammar> | |
See Also
