ViewFilter Class

Article
04/29/2015

This class handles various editing and IntelliSense commands for a language service.

This API is not CLS-compliant.

Inheritance Hierarchy

Object
Microsoft.VisualStudio.Package.ViewFilter

Namespace: Microsoft.VisualStudio.Package
Assemblies:   Microsoft.VisualStudio.Package.LanguageService.10.0 (in Microsoft.VisualStudio.Package.LanguageService.10.0.dll)
  Microsoft.VisualStudio.Package.LanguageService (in Microsoft.VisualStudio.Package.LanguageService.dll)
  Microsoft.VisualStudio.Package.LanguageService.12.0 (in Microsoft.VisualStudio.Package.LanguageService.12.0.dll)
  Microsoft.VisualStudio.Package.LanguageService.11.0 (in Microsoft.VisualStudio.Package.LanguageService.11.0.dll)
  Microsoft.VisualStudio.Package.LanguageService.9.0 (in Microsoft.VisualStudio.Package.LanguageService.9.0.dll)

Syntax

'Declaration
<CLSCompliantAttribute(False)> _
<ComVisibleAttribute(True)> _
Public Class ViewFilter _
    Implements IVsTextViewFilter, IVsTextViewEvents, IOleCommandTarget, IDisposable,  _
    IVsExpansionEvents

[CLSCompliantAttribute(false)]
[ComVisibleAttribute(true)]
public class ViewFilter : IVsTextViewFilter, IVsTextViewEvents, 
    IOleCommandTarget, IDisposable, IVsExpansionEvents

[CLSCompliantAttribute(false)]
[ComVisibleAttribute(true)]
public ref class ViewFilter : IVsTextViewFilter, 
    IVsTextViewEvents, IOleCommandTarget, IDisposable, IVsExpansionEvents

[<CLSCompliantAttribute(false)>]
[<ComVisibleAttribute(true)>]
type ViewFilter =  
    class 
        interface IVsTextViewFilter 
        interface IVsTextViewEvents 
        interface IOleCommandTarget 
        interface IDisposable 
        interface IVsExpansionEvents 
    end

public class ViewFilter implements IVsTextViewFilter, IVsTextViewEvents, IOleCommandTarget, IDisposable, IVsExpansionEvents

The ViewFilter type exposes the following members.

Constructors

	Name	Description
	ViewFilter	Initializes a new instance of the ViewFilter class.

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Properties

	Name	Description
	CodeWindowManager	Gets the CodeWindowManager that owns this ViewFilter.
	IsExecutingCommand	Determines whether or not the filter is executing commands.
	IsExpansionUIActive	Determines if the code snippet expansion user interface (UI) is active.
	SnippetBound	Gets or sets whether or not a key has been bound to the Invoke Snippet From Shortcut command.
	Source	Gets the Source associated with this ViewFilter.
	TextTipData	Gets or sets the TextTipData associated with this view.
	TextView	Gets the IVsTextView object associated with this ViewFilter object.

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Methods

	Name	Description
	CanReformat	Determines whether the source can be reformatted by the language service.
	Close	Closes down the view filter, releasing any allocated resources.
	CommentSelection	Handles the COMMENT_BLOCK command to comment out the current selection in the view.
	CreateTextTipData	Creates a new instance of the TextTipData class.
	Dispose	Frees up any resources allocated when the ViewFilter class was created.
	Equals	Determines whether the specified object is equal to the current object. (Inherited from Object.)
	ExecCommand	Executes the specified command.
	Finalize	Performs final clean up just before the ViewFilter object is destroyed. (Overrides Object.Finalize.)
	GetDataTipText	Returns text about the given span that can be shown in a tool tip.
	GetExpansionProvider	Returns an ExpansionProvider object.
	GetFullDataTipText	Returns a string that can be used in a tool tip, taking into account additional sources of text such as a debugger.
	GetHashCode	Serves as the default hash function. (Inherited from Object.)
	GetPairExtents	Returns the extent of the innermost matching pair of language elements that contains the given location.
	GetSelection	Returns the extent of the currently selected text.
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	GetWordExtent	Returns the extent of the word or expression that contains the given location.
	HandleGoto	Processes the specified "go to" command.
	HandlePostExec	Handles post-processing after a command has been executed.
	HandlePreExec	Handles pre-processing before a command is executed.
	HandleQuickInfo	Handles the QUICKINFO command to show tool tip information about the selected identifier or expression.
	HandleSmartIndent	Handles smart indentation.
	InnerExec	Executes an IOleCommandTarget command.
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	OnAfterSnippetsKeyBindingChange	Called after there has been a change in the key binding for the Invoke Snippet From Shortcut command.
	OnAfterSnippetsUpdate	Called whenever a folder that contains snippets has been updated and the snippets from that folder have been read in.
	OnAutoComplete	Called when the AUTOCOMPLETE command is received.
	OnChangeCaretLine	Called when the caret moves to another line.
	OnChangeScrollInfo	Called when the scroll information for the specified scroll bar has changed.
	OnKillFocus	Called when the specified view loses focus.
	OnSetBuffer	Called when the buffer of lines is being set or changed in the given view.
	OnSetFocus	Called when the specified view gains focus.
	QueryCommandStatus	Determines if the specified command is supported.
	QueryParameterList	Called to obtain the parameter for the specified command.
	ReformatDocument	Handles the FORMATDOCUMENT command to reformat the entire document.
	ReformatSelection	Handles the FORMATSELECTION command to reformat a selection.
	RegisterExpansionManagerEventHandlers	Registers event handlers IVsExpansionEvents.
	RegisterTextViewEventHandlers	Register text view event handlers.
	ShowContextMenu(Int32, Guid, IOleCommandTarget)
	ShowContextMenu(Int32, Guid, IOleCommandTarget, Int32, Int32)	Handles the SHOWCONTEXTMENU command to show a context menu.
	ToString	Returns a string that represents the current object. (Inherited from Object.)
	TypeChar	Executes a TYPECHAR on the current command target chain.
	UncommentSelection	Handles the UNCOMMENTBLOCK command to uncomment the current selection in the current view.

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Explicit Interface Implementations

	Name	Description
	IOleCommandTarget.Exec	Handles execution of a supported command.
	IOleCommandTarget.QueryStatus	Determines if the specified commands in the given command group are supported.

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Remarks

In addition to the cursor, Enter, Backspace, and Delete key commands, this base class provides support for the following commands:

Command	Description
AUTOCOMPLETE	IntelliSense: select member from member list.
SHOWMEMBERLIST	IntelliSense: show member list.
COMPLETEWORD	IntelliSense: complete word being typed.
PARAMINFO	IntelliSense: show parameter information.
QUICKINFO	IntelliSense: show information about an identifier.
GotoDefn	Editing (advanced): go to definition.
GotoDecl	Editing (advanced): go to declaration.
GotoRef	Editing (advanced): go to a reference.
COMMENT_BLOCK	Editing (advanced): comment a span of code.
UNCOMMENT_BLOCK	Editing (Advanced): uncomment a span of code.
OUTLN_STOP_HIDING_ALL	Editing (outlining): stop outlining.
OUTLN_START_AUTOHIDING	Editing (outlining): toggle outlining.
SHOWCONTEXTMENU	Editing: show a context menu.

Notes to Implementers

This class already implements all of the support for IntelliSense as well as various advanced editing features. However, if you want to support additional commands in your language service, then you must derive a class from this class and override the appropriate methods:

QueryCommandStatus (to indicate support for your commands)
QueryParameterList (if your commands require parameters)
HandlePreExec (if your commands require some set up)
HandlePostExec (if your commands require clean up after execution).
ExecCommand (to execute the command).

In addition, you must override the CreateViewFilter method in the LanguageService class to create an instance of your version of the ViewFilter class.

Notes to Callers

This class is instantiated in the CreateViewFilter method of the LanguageService class that is in turn called from the OnNewView method in the CodeWindowManager class when a view is attached to a source file.

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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