RequiresProvidesDirectiveProcessor Class

Article
10/10/2013

The abstract base class for a directive processor that defines and implements a design pattern called requires/provides.

Inheritance Hierarchy

System.Object
Microsoft.VisualStudio.TextTemplating.DirectiveProcessor
Microsoft.VisualStudio.TextTemplating.RequiresProvidesDirectiveProcessor

Namespace: Microsoft.VisualStudio.TextTemplating
Assembly: Microsoft.VisualStudio.TextTemplating.12.0 (in Microsoft.VisualStudio.TextTemplating.12.0.dll)

Syntax

'Declaration
Public MustInherit Class RequiresProvidesDirectiveProcessor _
    Inherits DirectiveProcessor

public abstract class RequiresProvidesDirectiveProcessor : DirectiveProcessor

public ref class RequiresProvidesDirectiveProcessor abstract : public DirectiveProcessor

[<AbstractClass>]
type RequiresProvidesDirectiveProcessor =  
    class 
        inherit DirectiveProcessor 
    end

public abstract class RequiresProvidesDirectiveProcessor extends DirectiveProcessor

The RequiresProvidesDirectiveProcessor type exposes the following members.

Constructors

	Name	Description
	RequiresProvidesDirectiveProcessor	When overridden in a derived class, initializes a new instance of the RequiresProvidesDirectiveProcessor class.

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Properties

	Name	Description
	Errors	Gets the errors that occurred when processing directives. (Inherited from DirectiveProcessor.)
	FriendlyName	When overridden in a derived class, gets the friendly name of the directive processor.
	Host	Gets the host that is associated with this directive processor.

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Methods

	Name	Description
	Equals	Determines whether the specified object is equal to the current object. (Inherited from Object.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
	FinishProcessingRun	Finishes a round of directive processing. (Overrides DirectiveProcessor.FinishProcessingRun().)
	GeneratePostInitializationCode	When overridden in a derived class, adds code to the initialization code for the generated transformation class. This code is added after the base class is initialized.
	GeneratePreInitializationCode	When overridden in a derived class, adds code to the initialization code of the generated transformation class. This code is added before the base class is initialized.
	GenerateTransformCode	When overridden in a derived class, adds code to the generated transformation class.
	GetClassCodeForProcessingRun	Gets code to add to the generated transformation class. (Overrides DirectiveProcessor.GetClassCodeForProcessingRun().)
	GetHashCode	Serves as the default hash function. (Inherited from Object.)
	GetImportsForProcessingRun	Gets namespaces to import into the generated transformation class. (Overrides DirectiveProcessor.GetImportsForProcessingRun().)
	GetPostInitializationCodeForProcessingRun	Gets code to initialize when the generated transformation class is initialized, as a consequence of the most recent processing run. (Overrides DirectiveProcessor.GetPostInitializationCodeForProcessingRun().)
	GetPreInitializationCodeForProcessingRun	Gets code to initialize when the generated transformation class is initialized, as a consequence of the most recent processing run. (Overrides DirectiveProcessor.GetPreInitializationCodeForProcessingRun().)
	GetReferencesForProcessingRun	Gets references to pass to the compiler of the generated transformation class. (Overrides DirectiveProcessor.GetReferencesForProcessingRun().)
	GetTemplateClassCustomAttributes	Get any custom attributes to put on the template class. (Inherited from DirectiveProcessor.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	Initialize	Initializes an instance of the directive processor. (Overrides DirectiveProcessor.Initialize(ITextTemplatingEngineHost).)
	InitializeProvidesDictionary	When overridden in a derived class, specifies the provides parameters for each directive.
	InitializeRequiresDictionary	When overridden in a derived class, specifies the requires parameters for each directive.
	IsDirectiveSupported	When overridden in a derived class, determines whether the directive processor supports the specified directive. (Inherited from DirectiveProcessor.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	PostProcessArguments	When overridden in a derived class, allows derived classes to make any modifications to the parameters that they provide and require.
	ProcessDirective	Processes a single directive from a text template file. (Overrides DirectiveProcessor.ProcessDirective(String, IDictionary<String, String>).)
	ProvideUniqueId	Provides an ID that identifies a call to the directive processor.
	StartProcessingRun	Starts a directive processor. (Overrides DirectiveProcessor.StartProcessingRun(CodeDomProvider, String, CompilerErrorCollection).)
	ToString	Returns a string that represents the current object. (Inherited from Object.)

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Explicit Interface Implementations

	Name	Description
	IDirectiveProcessor.Errors	(Inherited from DirectiveProcessor.)
	IDirectiveProcessor.RequiresProcessingRunIsHostSpecific	(Inherited from DirectiveProcessor.)
	IDirectiveProcessor.SetProcessingRunIsHostSpecific	(Inherited from DirectiveProcessor.)

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Remarks

To create a custom directive processor, you create a class that inherits from either DirectiveProcessor or RequiresProvidesDirectiveProcessor.

DirectiveProcessor implements the interface that is required to capture parameters from the user, and provides functionality for the generated transformation class. RequiresProvidesDirectiveProcessorRequiresProvidesDirectiveProcessor implements the design pattern, requires/provides, for your directive processor. RequiresProvidesDirectiveProcessor provides additional facilities to capture parameters from the user, and provides functionality to the generated transformation class with specific property names.

For more information, see Creating Custom T4 Text Template Directive Processors.

The transformation engine holds a singleton for any required RequiresProvidesDirectiveProcessor class.

RequiresProvidesDirectiveProcessor implements a state machine.

For example, if a text template has three directive calls to the same directive processor, the engine calls the following methods in order:

StartProcessingRun
ProcessDirective
ProcessDirective
ProcessDirective
FinishProcessingRun
GetClassCodeForProcessingRun
GetPreInitializationCodeForProcessingRun
GetPostInitializationCodeForProcessingRun

Examples

The following example demonstrates how to use the RequiresProvidesDirectiveProcessor.

using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.VisualStudio.TextTemplating;
using System.Xml;
using System.IO;
using System.Globalization;

namespace Microsoft.Samples.VisualStudio.TextTemplating.DirectiveProcessors
{
public class DomDirectiveProcessor : RequiresProvidesDirectiveProcessor
{

// Name of the tag that this directive processor supports.
private const string DomDirectiveTag = "dom";

//Name of the parameter that must be provided for this directive processor to load an XML file
private const string XmlFileRequiredParameterName = "XmlFile";

// Default name of the property that this provider adds to the generated transform class.
private const string DomProvidedParameterName = "Dom";

// Set up the dictionary of items that this directive processor will provide.
protected override void InitializeProvidesDictionary(string directiveName, IDictionary<string, string> providesDictionary)
{
if (StringComparer.InvariantCultureIgnoreCase.Compare(directiveName, DomDirectiveTag) == 0)
{
// Populate the dictionary with defualt names.
providesDictionary[DomProvidedParameterName] = DomProvidedParameterName;
}
}

// Set up the dictionary of items that this directive processor requires to complete.
protected override void InitializeRequiresDictionary(string directiveName, IDictionary<string, string> requiresDictionary)
{
if (StringComparer.InvariantCultureIgnoreCase.Compare(directiveName, DomDirectiveTag) == 0)
{
// Initialize the dictionary with nulls for each required parameter.
requiresDictionary[XmlFileRequiredParameterName] = null;
}
}
}
}

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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