ProvideLanguageServiceAttribute Class

Informs Visual Studio that a VSPackage provides a language service. Used with the managed package framework (MPF).


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

[AttributeUsageAttribute(AttributeTargets.Class, AllowMultiple = true, Inherited = true)]
public sealed class ProvideLanguageServiceAttribute : RegistrationAttribute

The ProvideLanguageServiceAttribute type exposes the following members.

Public methodProvideLanguageServiceAttributeInitializes a new instance of the Shell.ProvideLanguageServiceAttribute class.

Public propertyAutoOutliningDetermines if the language service supports automatic outlining.
Public propertyCodeSenseDetermines if the language service supports IntelliSense operations.
Public propertyCodeSenseDelayDetermines the amount of time before a parse operation is started to support an IntelliSense operation.
Public propertyDebuggerLanguageExpressionEvaluatorDetermines the expression evaluator that is used for evaluating expressions.
Public propertyDefaultToInsertSpacesDetermines the default setting for the Insert spaces option in the Options dialog box for a language service.
Public propertyDefaultToNonHotURLsDetermines the initial setting of the Enable single-click URL navigation option in the Options dialog box.
Public propertyEnableAdvancedMembersOptionDetermines whether the Hide Advanced Members option is enabled in the Options dialog box.
Public propertyEnableAsyncCompletionDetermines whether the language supports background parsing.
Public propertyEnableCommentingDetermines whether the language service can comment and uncomment source code using a single command.
Public propertyEnableFormatSelectionDetermines if the language service supports automatic formatting of the source code.
Public propertyEnableLineNumbersDetermines if the Line numbers option can be selected in the Options dialog box.
Public propertyHideAdvancedMembersByDefaultDetermines the initial state of the Hide Advanced Members option in the Options dialog box.
Public propertyLanguageNameInfrastructure. Returns the name of the language.
Public propertyLanguageResourceIDInfrastructure. Returns the resource ID used to obtain the localized version of the language name.
Public propertyLanguageServiceSidInfrastructure. Returns the GUID of the language service.
Public propertyMatchBracesDetermines if the language service supports matching language pairs.
Public propertyMatchBracesAtCaretDetermines if a language service supports matching language pairs while typing.
Public propertyMaxErrorMessagesDetermines the maximum number of errors message that a language service can report for a parsing operation.
Public propertyQuickInfoDetermines if the language service supports the IntelliSense Quick Info.
Public propertyRequestStockColorsDetermines if the language service is using the built-in colorable items as supplied by Visual Studio.
Public propertyShowCompletionDetermines if the Statement completion options are enabled in the Options dialog box.
Public propertyShowDropDownOptionsDetermines if the Navigation bar option is enabled in the Options dialog box.
Public propertyShowHotURLsDetermines if URLs are displayed in such a way as to show they can be clicked. This option is not used.
Public propertyShowMatchingBraceDetermines if the matching language pair is shown in the status bar.
Public propertyShowSmartIndentDetermines if the Smart Indenting option is enabled in the Options dialog box.
Public propertySingleCodeWindowOnlyDetermines if the Window -> New Window command is disabled for a language service.
Public propertySupportCopyPasteOfHTMLDetermines if the language service supports the clipboard format HTML for copy and paste operations.
Public propertyTypeIdGets the current instance of this attribute. (Inherited from RegistrationAttribute.)

Public methodEqualsInfrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)
Public methodGetHashCodeReturns the hash code for this instance. (Inherited from Attribute.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodIsDefaultAttributeWhen overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)
Public methodMatchWhen overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Public methodRegisterInfrastructure. Creates all of the registry keys and entries as specified by the class constructor. (Overrides RegistrationAttribute.Register(RegistrationAttribute.RegistrationContext).)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
Public methodUnregisterRemoves all of the registry keys and entries as specified by the class constructor. (Overrides RegistrationAttribute.Unregister(RegistrationAttribute.RegistrationContext).)

Explicit interface implemetationPrivate method_Attribute.GetIDsOfNamesMaps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoRetrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoCountRetrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.InvokeProvides access to properties and methods exposed by an object. (Inherited from Attribute.)

This user-defined attribute (which is specific to Visual C#) is used to provide information necessary to register a language service with Visual Studio. The values specified by this attribute are stored as metadata in the assembly. This metadata is later used by a program such as regpkg.exe (part of the VSIP SDK) to create the corresponding registry keys and entries that tell Visual Studio about the language service.

The registry entries affected by the ProvideLanguageServiceAttribute are found under the following registry key:

            Language Services\
              [language name]\
                (Default) = reg_sz: [Language Service GUID]
                Package   = reg_sz: [Package GUID]
                LangResID = reg_dword: [language name resource ID]

Where [X.Y] is the version of Visual Studio, for example, 8.0Exp, and [language name] is the name of the language (as specified in the second parameter to the ProvideLanguageServiceAttribute class constructor).


Each property specifies the exact registry entry it affects so those entries are not shown in the above example. Those additional entries appear at the same level as the three entries shown.

The class constructor specifies the minimum required parameters. A user-defined attribute class also supports optional named parameters. These named parameters are specified in the constructor's parameter list after the required parameters. All of the properties on this class that support both get and set operators can be specified as a named parameter. The Example shows how named parameters are used.


Some of the named parameters are specific to the managed package framework (MPF) and these are noted in each property description.

The following user-defined attributes are used for language services:




Registers the language service with Visual Studio and specifies what features are supported.


Associates a file extension with the language service.


Specifies a property node or page for the Options dialog box specific to the language service.


Specifies location information to support code snippets in the language service.


Registers a language service as a Visual Studio service. All services supplied in managed code use this attribute.

Notes to Implementers

This attribute class cannot be inherited from so there is nothing to implement.

Notes to Callers

This attribute class is typically applied to your primary VSPackage class, although it can appear on any class. This class should appear only once for each language service your VSPackage supports.

This example shows how this user-defined attribute is used to register a language service that supports IntelliSense operations, brace matching, asynchronous (background) parsing, and custom colorable items.


Visual C# allows for a shorthand form of a user-defined attribute by dropping the "Attribute" part of the name. This shorthand form is used in this and all other examples throughout this class.

using Microsoft.VisualStudio.Shell;

namespace MyLanguagePackage
    internal class MyConstants
        public const string languageName           = "MyLanguage";
        public const int    languageNameResourceID = 106;

        // Optional language service properties
        CodeSense             = true,  // General IntelliSense support
        RequestStockColors    = false, // Custom colorable items
        EnableASyncCompletion = true,  // supports background parsing
        MatchBraces           = true,  // Match braces on command
        MatchBracesAtCaret    = true   // Match braces while typing

    class MyLanguagePackage

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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