Walkthrough: Displaying QuickInfo Tooltips
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QuickInfo is an IntelliSense feature that displays method signatures and descriptions when a user moves the pointer over a method name. You can implement language-based features such as QuickInfo by defining the identifiers for which you want to provide QuickInfo descriptions, and then creating a tooltip in which to display the content. You can define QuickInfo in the context of a language service, or you can define your own file name extension and content type and display the QuickInfo for just that type, or you can display QuickInfo for an existing content type (such as "text"). This walkthrough shows how to display QuickInfo for the "text" content type.
The QuickInfo example in this walkthrough displays the tooltips when a user moves the pointer over a method name. This design requires you to implement these four interfaces:
source interface
source provider interface
controller interface
controller provider interface
The source and controller providers are Managed Extensibility Framework (MEF) component parts, and are responsible for exporting the source and controller classes and importing services and brokers such as the ITextBufferFactoryService, which creates the tooltip text buffer, and the IQuickInfoBroker, which triggers the QuickInfo session.
In this example, the QuickInfo source uses a hard-coded list of method names and descriptions, but in full implementations, the language service and the language documentation are responsible for providing that content.
Starting in Visual Studio 2015, you do not install the Visual Studio SDK from the download center. It is included as an optional feature in Visual Studio setup. You can also install the VS SDK later on. For more information, see Installing the Visual Studio SDK.
To create a MEF project
Create a C# VSIX project. (In the New Project dialog, select Visual C# / Extensibility, then VSIX Project.) Name the solution
QuickInfoTest.Add an Editor Classifier item template to the project. For more information, see Creating an Extension with an Editor Item Template.
Delete the existing class files.
The QuickInfo source is responsible for collecting the set of identifiers and their descriptions and adding the content to the tooltip text buffer when one of the identifiers is encountered. In this example, the identifiers and their descriptions are just added in the source constructor.
To implement the QuickInfo source
Add a class file and name it
TestQuickInfoSource.Add a reference to Microsoft.VisualStudio.Language.IntelliSense.
Add the following imports.
Imports System Imports System.Collections.Generic Imports System.Linq Imports System.Text Imports System.Collections.ObjectModel Imports System.ComponentModel.Composition Imports Microsoft.VisualStudio.Language.Intellisense Imports Microsoft.VisualStudio.Text Imports Microsoft.VisualStudio.Text.Editor Imports Microsoft.VisualStudio.Text.Operations Imports Microsoft.VisualStudio.Text.Tagging Imports Microsoft.VisualStudio.Utilities
Declare a class that implements IQuickInfoSource, and name it
TestQuickInfoSource.Add fields for the QuickInfo source provider, the text buffer, and a set of method names and method signatures. In this example, the method names and signatures are initialized in the
TestQuickInfoSourceconstructor.Add a constructor that sets the QuickInfo source provider and the text buffer, and populates the set of method names, and method signatures and descriptions.
Public Sub New(ByVal provider As TestQuickInfoSourceProvider, ByVal subjectBuffer As ITextBuffer) m_provider = provider m_subjectBuffer = subjectBuffer 'these are the method names and their descriptions m_dictionary = New Dictionary(Of String, String)() m_dictionary.Add("add", "int add(int firstInt, int secondInt)" & vbLf & "Adds one integer to another.") m_dictionary.Add("subtract", "int subtract(int firstInt, int secondInt)" & vbLf & "Subtracts one integer from another.") m_dictionary.Add("multiply", "int multiply(int firstInt, int secondInt)" & vbLf & "Multiplies one integer by another.") m_dictionary.Add("divide", "int divide(int firstInt, int secondInt)" & vbLf & "Divides one integer by another.") End SubImplement the AugmentQuickInfoSession method. In this example, the method finds the current word, or the previous word if the cursor is at the end of a line or a text buffer. If the word is one of the method names, the description for that method name is added to the QuickInfo content.
Public Sub AugmentQuickInfoSession(ByVal session As IQuickInfoSession, ByVal qiContent As IList(Of Object), ByRef applicableToSpan As ITrackingSpan) Implements IQuickInfoSource.AugmentQuickInfoSession ' Map the trigger point down to our buffer. Dim subjectTriggerPoint As System.Nullable(Of SnapshotPoint) = session.GetTriggerPoint(m_subjectBuffer.CurrentSnapshot) If Not subjectTriggerPoint.HasValue Then applicableToSpan = Nothing Exit Sub End If Dim currentSnapshot As ITextSnapshot = subjectTriggerPoint.Value.Snapshot Dim querySpan As New SnapshotSpan(subjectTriggerPoint.Value, 0) 'look for occurrences of our QuickInfo words in the span Dim navigator As ITextStructureNavigator = m_provider.NavigatorService.GetTextStructureNavigator(m_subjectBuffer) Dim extent As TextExtent = navigator.GetExtentOfWord(subjectTriggerPoint.Value) Dim searchText As String = extent.Span.GetText() For Each key As String In m_dictionary.Keys Dim foundIndex As Integer = searchText.IndexOf(key, StringComparison.CurrentCultureIgnoreCase) If foundIndex > -1 Then 'applicableToSpan = currentSnapshot.CreateTrackingSpan(querySpan.Start.Add(foundIndex).Position, 9, SpanTrackingMode.EdgeInclusive) applicableToSpan = currentSnapshot.CreateTrackingSpan(extent.Span.Start + foundIndex, key.Length, SpanTrackingMode.EdgeInclusive) Dim value As String = "" m_dictionary.TryGetValue(key, value) If value IsNot Nothing Then qiContent.Add(value) Else qiContent.Add("") End If Exit Sub End If Next applicableToSpan = Nothing End SubYou must also implement a Dispose() method, since IQuickInfoSource implements IDisposable:
The provider of the QuickInfo source serves primarily to export itself as a MEF component part and instantiate the QuickInfo source. Because it is a MEF component part, it can import other MEF component parts.
To implement a QuickInfo source provider
Declare a QuickInfo source provider named
TestQuickInfoSourceProviderthat implements IQuickInfoSourceProvider, and export it with a NameAttribute of "ToolTip QuickInfo Source", an OrderAttribute of Before="default", and a ContentTypeAttribute of "text".Import two editor services, ITextStructureNavigatorSelectorService and ITextBufferFactoryService, as properties of
TestQuickInfoSourceProvider.Private _NavigatorService As ITextStructureNavigatorSelectorService <Import()> _ Friend Property NavigatorService() As ITextStructureNavigatorSelectorService Get Return _NavigatorService End Get Set(ByVal value As ITextStructureNavigatorSelectorService) _NavigatorService = value End Set End Property Private _TextBufferFactoryService As ITextBufferFactoryService <Import()> _ Friend Property TextBufferFactoryService() As ITextBufferFactoryService Get Return _TextBufferFactoryService End Get Set(ByVal value As ITextBufferFactoryService) _TextBufferFactoryService = value End Set End PropertyImplement TryCreateQuickInfoSource to return a new
TestQuickInfoSource.
QuickInfo controllers determine when QuickInfo should be displayed. In this example, QuickInfo is displayed when the pointer is over a word that corresponds to one of the method names. The QuickInfo controller implements a mouse hover event handler that triggers a QuickInfo session.
To implement a QuickInfo controller
Declare a class that implements IIntellisenseController, and name it
TestQuickInfoController.Add private fields for the text view, the text buffers represented in the text view, the QuickInfo session, and the QuickInfo controller provider.
Add a constructor that sets the fields and adds the mouse hover event handler.
Friend Sub New(ByVal textView As ITextView, ByVal subjectBuffers As IList(Of ITextBuffer), ByVal provider As TestQuickInfoControllerProvider) m_textView = textView m_subjectBuffers = subjectBuffers m_provider = provider AddHandler m_textView.MouseHover, AddressOf Me.OnTextViewMouseHover End SubAdd the mouse hover event handler that triggers the QuickInfo session.
Private Sub OnTextViewMouseHover(ByVal sender As Object, ByVal e As MouseHoverEventArgs) 'find the mouse position by mapping down to the subject buffer Dim point As System.Nullable(Of SnapshotPoint) = m_textView.BufferGraph.MapDownToFirstMatch(New SnapshotPoint(m_textView.TextSnapshot, e.Position), PointTrackingMode.Positive, Function(snapshot) m_subjectBuffers.Contains(snapshot.TextBuffer), PositionAffinity.Predecessor) If point IsNot Nothing Then Dim triggerPoint As ITrackingPoint = point.Value.Snapshot.CreateTrackingPoint(point.Value.Position, PointTrackingMode.Positive) If Not m_provider.QuickInfoBroker.IsQuickInfoActive(m_textView) Then m_session = m_provider.QuickInfoBroker.TriggerQuickInfo(m_textView, triggerPoint, True) End If End If End SubImplement the Detach method so that it removes the mouse hover event handler when the controller is detached from the text view.
Implement the ConnectSubjectBuffer method and the DisconnectSubjectBuffer method as empty methods for this example.
The provider of the QuickInfo controller serves primarily to export itself as a MEF component part and instantiate the QuickInfo controller. Because it is a MEF component part, it can import other MEF component parts.
To implement the QuickInfo controller provider
Declare a class named
TestQuickInfoControllerProviderthat implements IIntellisenseControllerProvider, and export it with a NameAttribute of "ToolTip QuickInfo Controller" and a ContentTypeAttribute of "text":Import the IQuickInfoBroker as a property.
Implement the TryCreateIntellisenseController method by instantiating the QuickInfo controller.
Public Function TryCreateIntellisenseController(ByVal textView As ITextView, ByVal subjectBuffers As IList(Of ITextBuffer)) As IIntellisenseController Implements IIntellisenseControllerProvider.TryCreateIntellisenseController Return New TestQuickInfoController(textView, subjectBuffers, Me) End Function
To test this code, build the QuickInfoTest solution and run it in the experimental instance.
To build and test the QuickInfoTest solution
Build the solution.
When you run this project in the debugger, a second instance of Visual Studio is instantiated.
Create a text file and type some text that includes the words "add" and "subtract".
Move the pointer over one of the occurrences of "add". The signature and the description of the
addmethod should be displayed.
Walkthrough: Linking a Content Type to a File Name Extension