Walkthrough: Using a Shell Command with an Editor Extension

Article
01/30/2013

From a VSPackage, you can add features such as menu commands to the editor. This walkthrough shows how to add an adornment to a text view in the editor by invoking a menu command.

This walkthrough demonstrates the use of a VSPackage together with a Managed Extensibility Framework (MEF) component part. You must use a VSPackage to register the menu command with the Visual Studio shell, and you can use the command to access the MEF component part.

Prerequisites

To complete this walkthrough, you must install the Visual Studio 2010 SDK.

Note

For more information about the Visual Studio SDK, see Visual Studio Integration SDK. To find out how to download the Visual Studio SDK, see Visual Studio Extensibility Developer Center on the MSDN Web site.

Locations for the Visual Studio Package Project Template

The Visual Studio Package project template can be found in three different locations in the New Project dialog:

Under Visual Basic Extensibility. The default language of the project is Visual Basic.
Under C# Extensibility. The default language of the project is C#.
Under Other Project Types Extensibility. The default language of the project is C++

Create a VSPackage that puts a menu command named Add Adornment on the Tools menu.

Create a Visual Studio Package and name it MenuCommandTest. Click OK.
On the welcome page, click Next.
On the Select a Programming Language page, select Visual Basic or Visual C#, make sure that Generate a new key file to sign the assembly is selected, and then click Next.
On the Basic VSPackage Information page, in the VSPackage name box type MenuCommand, and then click Next.
On the Select VSPackage Options page, select Menu Command and then click Next.
On the Command Options page, in the Command name box type Add Adornment. In the Command ID box, type cmdidAddAdornment. Click Next.
On the Select Test Options page, clear both options and then click Finish.
A solution named MenuCommandTest is opened. The MenuCommandTestPackage file has the code that creates the menu command and puts it on the Tools menu. At this point, the command just causes a message box to be displayed. Later steps show how to change this to display the comment adornment.
Open the source.extension.vsixmanifest file in the VSIX Manifest Editor. It should have one Content row for a VSPackage named MenuCommand.
Save and close the Source.extension.vsixmanifest file.

Adding a MEF Extension to the VSPackage Solution

To add the MEF extension to the VSPackage solution

In Solution Explorer, right-click the solution node, click Add, and then click New Project. In the Add New Project dialog box, click Extensibility under Visual Basic or Visual C#, then EditorClassifier. Name the project CommentAdornmentTest.
Because this project will interact with the strongly-named VSPackage assembly, you must sign the assembly. You can reuse the key file already created for the VSPackage assembly.
1. Open the project properties and select the Signing page.
2. Select Sign the assembly.
3. Under Choose a strong name key file, select the Key.snk file that was generated for the MenuCommandTest assembly.
4. Save the project.

Referring to the MEF Extension in the VSPackage Project

Because you are adding a MEF component to the VSPackage, you must specify both kinds of content in the manifest.

Note

For more information about MEF, see Managed Extensibility Framework Overview.

To refer to the MEF component in the VSPackage project

In the MenuCommandTest project, open the source.extension.vsixmanifest file in the VSIX Manifest Editor.
Under the Content heading, click Add Content. On the Select content type list, select MEF Component. Under Select a source, select CommentAdornmentTest.
Save and close the source.extension.vsixmanifest file.
Add a reference to the CommentAdornmentTest project.

Defining a Comment Adornment

The comment adornment itself consists of an ITrackingSpan that tracks the selected text, and some strings that represent the author and the description of the text.

To define a comment adornment

In the CommentAdornmentTest project, delete the existing class files.
Add a new class file and name it CommentAdornment.

Add the following using statement.

Imports Microsoft.VisualStudio.Text

using Microsoft.VisualStudio.Text;

Add a class named CommentAdornment.

Friend Class CommentAdornment

internal class CommentAdornment

Add three fields to the CommentAdornment class for the ITrackingSpan, the author, and the description.

Public ReadOnly Span As ITrackingSpan
Public ReadOnly Author As String
Public ReadOnly Text As String

public readonly ITrackingSpan Span;
public readonly string Author;
public readonly string Text;

Add a constructor that initializes the fields.

Public Sub New(ByVal span As SnapshotSpan, ByVal author As String, ByVal text As String)
    Me.Span = span.Snapshot.CreateTrackingSpan(span, SpanTrackingMode.EdgeExclusive)
    Me.Author = author
    Me.Text = text
End Sub

public CommentAdornment(SnapshotSpan span, string author, string text)
{
    this.Span = span.Snapshot.CreateTrackingSpan(span, SpanTrackingMode.EdgeExclusive);
    this.Author = author;
    this.Text = text;
}

Creating a Visual Element for the Adornment

You must also define a visual element for your adornment. For this walkthrough, define a control that inherits from the Windows Presentation Foundation (WPF) class Canvas.

To create a visual element for the adornment

Create a class in the CommentAdornmentTest project and name it CommentBlock.

Add the following using statements.

Imports System
Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Media
Imports System.Windows.Shapes

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Shapes;

Make the CommentBlock class inherit from Canvas.

Friend Class CommentBlock
    Inherits Canvas

internal class CommentBlock : Canvas

Add some private fields to define the visual aspects of the adornment.

Private textGeometry As Geometry
Private commentGrid As Grid
Private Shared brush As Brush
Private Shared solidPen As Pen
Private Shared dashPen As Pen

private Geometry textGeometry;
private Grid commentGrid;
private static Brush brush;
private static Pen solidPen;
private static Pen dashPen;

Add a constructor that defines the comment adornment and adds the relevant text.

Public Sub New(ByVal textRightEdge As Double, ByVal viewRightEdge As Double, ByVal newTextGeometry As Geometry, ByVal author As String, ByVal body As String)
    If brush Is Nothing Then
        brush = New SolidColorBrush(Color.FromArgb(&H20, &H0, &HFF, &H0))
        brush.Freeze()
        Dim penBrush As Brush = New SolidColorBrush(Colors.Green)
        penBrush.Freeze()
        solidPen = New Pen(penBrush, 0.5)
        solidPen.Freeze()
        dashPen = New Pen(penBrush, 0.5)
        dashPen.DashStyle = DashStyles.Dash
        dashPen.Freeze()
    End If

    Me.textGeometry = newTextGeometry

    Dim tb1 As New TextBlock()
    tb1.Text = author
    Dim tb2 As New TextBlock()
    tb2.Text = body

    Const MarginWidth As Integer = 8
    Me.commentGrid = New Grid()
    Me.commentGrid.RowDefinitions.Add(New RowDefinition())
    Me.commentGrid.RowDefinitions.Add(New RowDefinition())
    Dim cEdge As New ColumnDefinition()
    cEdge.Width = New GridLength(MarginWidth)
    Dim cEdge2 As New ColumnDefinition()
    cEdge2.Width = New GridLength(MarginWidth)
    Me.commentGrid.ColumnDefinitions.Add(cEdge)
    Me.commentGrid.ColumnDefinitions.Add(New ColumnDefinition())
    Me.commentGrid.ColumnDefinitions.Add(cEdge2)

    Dim rect As New System.Windows.Shapes.Rectangle()
    rect.RadiusX = 6
    rect.RadiusY = 3
    rect.Fill = brush
    rect.Stroke = Brushes.Green

    Dim inf As New Size(Double.PositiveInfinity, Double.PositiveInfinity)
    tb1.Measure(inf)
    tb2.Measure(inf)
    Dim middleWidth As Double = Math.Max(tb1.DesiredSize.Width, tb2.DesiredSize.Width)
    Me.commentGrid.Width = middleWidth + 2 * MarginWidth
    Grid.SetColumn(rect, 0)
    Grid.SetRow(rect, 0)
    Grid.SetRowSpan(rect, 2)
    Grid.SetColumnSpan(rect, 3)
    Grid.SetRow(tb1, 0)
    Grid.SetColumn(tb1, 1)
    Grid.SetRow(tb2, 1)
    Grid.SetColumn(tb2, 1)
    Me.commentGrid.Children.Add(rect)
    Me.commentGrid.Children.Add(tb1)
    Me.commentGrid.Children.Add(tb2)

    Canvas.SetLeft(Me.commentGrid, Math.Max(viewRightEdge - Me.commentGrid.Width - 20.0, textRightEdge + 20.0))
    Canvas.SetTop(Me.commentGrid, textGeometry.GetRenderBounds(solidPen).Top)

    Me.Children.Add(Me.commentGrid)
End Sub

public CommentBlock(double textRightEdge,
double viewRightEdge,
Geometry newTextGeometry,
string author,
string body)
{
    if (brush == null)
    {
        brush = new SolidColorBrush(Color.FromArgb(0x20, 0x00, 0xff, 0x00));
        brush.Freeze();
        Brush penBrush = new SolidColorBrush(Colors.Green);
        penBrush.Freeze();
        solidPen = new Pen(penBrush, 0.5);
        solidPen.Freeze();
        dashPen = new Pen(penBrush, 0.5);
        dashPen.DashStyle = DashStyles.Dash;
        dashPen.Freeze();
    }

    this.textGeometry = newTextGeometry;

    TextBlock tb1 = new TextBlock();
    tb1.Text = author;
    TextBlock tb2 = new TextBlock();
    tb2.Text = body;

    const int MarginWidth = 8;
    this.commentGrid = new Grid();
    this.commentGrid.RowDefinitions.Add(new RowDefinition());
    this.commentGrid.RowDefinitions.Add(new RowDefinition());
    ColumnDefinition cEdge = new ColumnDefinition();
    cEdge.Width = new GridLength(MarginWidth);
    ColumnDefinition cEdge2 = new ColumnDefinition();
    cEdge2.Width = new GridLength(MarginWidth);
    this.commentGrid.ColumnDefinitions.Add(cEdge);
    this.commentGrid.ColumnDefinitions.Add(new ColumnDefinition());
    this.commentGrid.ColumnDefinitions.Add(cEdge2);

    System.Windows.Shapes.Rectangle rect = new System.Windows.Shapes.Rectangle();
    rect.RadiusX = 6;
    rect.RadiusY = 3;
    rect.Fill = brush;
    rect.Stroke = Brushes.Green;

    Size inf = new Size(double.PositiveInfinity, double.PositiveInfinity);
    tb1.Measure(inf);
    tb2.Measure(inf);
    double middleWidth = Math.Max(tb1.DesiredSize.Width, tb2.DesiredSize.Width);
    this.commentGrid.Width = middleWidth + 2 * MarginWidth;

    Grid.SetColumn(rect, 0);
    Grid.SetRow(rect, 0);
    Grid.SetRowSpan(rect, 2);
    Grid.SetColumnSpan(rect, 3);
    Grid.SetRow(tb1, 0);
    Grid.SetColumn(tb1, 1);
    Grid.SetRow(tb2, 1);
    Grid.SetColumn(tb2, 1);
    this.commentGrid.Children.Add(rect);
    this.commentGrid.Children.Add(tb1);
    this.commentGrid.Children.Add(tb2);

    Canvas.SetLeft(this.commentGrid, Math.Max(viewRightEdge - this.commentGrid.Width - 20.0, textRightEdge + 20.0));
    Canvas.SetTop(this.commentGrid, textGeometry.GetRenderBounds(solidPen).Top);

    this.Children.Add(this.commentGrid);
}

Also implement an OnRender event handler that draws the adornment.

Protected Overrides Sub OnRender(ByVal dc As DrawingContext)
    MyBase.OnRender(dc)
    If Me.textGeometry IsNot Nothing Then
        dc.DrawGeometry(brush, solidPen, Me.textGeometry)
        Dim textBounds As Rect = Me.textGeometry.GetRenderBounds(solidPen)
        Dim p1 As New Point(textBounds.Right, textBounds.Bottom)
        Dim p2 As New Point(Math.Max(Canvas.GetLeft(Me.commentGrid) - 20.0, p1.X), p1.Y)
        Dim p3 As New Point(Math.Max(Canvas.GetLeft(Me.commentGrid), p1.X), (Canvas.GetTop(Me.commentGrid) + p1.Y) * 0.5)
        dc.DrawLine(dashPen, p1, p2)
        dc.DrawLine(dashPen, p2, p3)
    End If
End Sub

protected override void OnRender(DrawingContext dc)
{
    base.OnRender(dc);
    if (this.textGeometry != null)
    {
        dc.DrawGeometry(brush, solidPen, this.textGeometry);
        Rect textBounds = this.textGeometry.GetRenderBounds(solidPen);
        Point p1 = new Point(textBounds.Right, textBounds.Bottom);
        Point p2 = new Point(Math.Max(Canvas.GetLeft(this.commentGrid) - 20.0, p1.X), p1.Y);
        Point p3 = new Point(Math.Max(Canvas.GetLeft(this.commentGrid), p1.X), (Canvas.GetTop(this.commentGrid) + p1.Y) * 0.5);
        dc.DrawLine(dashPen, p1, p2);
        dc.DrawLine(dashPen, p2, p3);
    }
}

Adding an IWpfTextViewCreationListener

The IWpfTextViewCreationListener is a MEF component part that you can use to listen to view creation events.

To add an IWpfTextViewCreationListener

Add a class file to the CommentAdornmentTest project and name it Connector.

Add the following using statements.

Imports System.ComponentModel.Composition
Imports Microsoft.VisualStudio.Text.Editor
Imports Microsoft.VisualStudio.Utilities

using System.ComponentModel.Composition;
using Microsoft.VisualStudio.Text.Editor;
using Microsoft.VisualStudio.Utilities;

Declare a class that implements IWpfTextViewCreationListener and export it with a ContentTypeAttribute of "text" and a TextViewRoleAttribute of Document. The content type attribute specifies the kind of content to which the component applies. The text type is the base type for all non-binary file types. Therefore, almost every text view that is created will be of this type. The text view role attribute specifies the kind of text view to which the component applies. Document text view roles generally show text that is composed of lines and is stored in a file.
```
<Export(GetType(IWpfTextViewCreationListener)), ContentType("text"), TextViewRole(PredefinedTextViewRoles.Document)>
Public NotInheritable Class Connector
    Implements IWpfTextViewCreationListener
```
```
[Export(typeof(IWpfTextViewCreationListener))]
[ContentType("text")]
[TextViewRole(PredefinedTextViewRoles.Document)]
public sealed class Connector : IWpfTextViewCreationListener
```

Implement the TextViewCreated method so that it calls the static Create() event of the CommentAdornmentManager.

Public Sub TextViewCreated(ByVal textView As IWpfTextView) Implements IWpfTextViewCreationListener.TextViewCreated
    CommentAdornmentManager.Create(textView)
End Sub

public void TextViewCreated(IWpfTextView textView)
{
    CommentAdornmentManager.Create(textView);
}

Add a method that you can use to execute the command.

Public Shared Sub Execute(ByVal host As IWpfTextViewHost)
    Dim view As IWpfTextView = host.TextView
    'Add a comment on the selected text.
    If Not view.Selection.IsEmpty Then
        'Get the provider for the comment adornments in the property bag of the view.
        Dim provider As CommentAdornmentProvider = view.Properties.GetProperty(Of CommentAdornmentProvider)(GetType(CommentAdornmentProvider))

        'Add some arbitrary author and comment text.
        Dim author As String = System.Security.Principal.WindowsIdentity.GetCurrent().Name
        Dim comment As String = "Four score...."

        'Add the comment adornment using the provider.
        provider.Add(view.Selection.SelectedSpans(0), author, comment)
    End If
End Sub

static public void Execute(IWpfTextViewHost host)
{
    IWpfTextView view = host.TextView;
    //Add a comment on the selected text.
    if (!view.Selection.IsEmpty)
    {
        //Get the provider for the comment adornments in the property bag of the view.
        CommentAdornmentProvider provider = view.Properties.GetProperty<CommentAdornmentProvider>(typeof(CommentAdornmentProvider));

        //Add some arbitrary author and comment text.
        string author = System.Security.Principal.WindowsIdentity.GetCurrent().Name;
        string comment = "Four score....";

        //Add the comment adornment using the provider.
        provider.Add(view.Selection.SelectedSpans[0], author, comment);
    }
}

Defining an Adornment Layer

To add a new adornment, you must define an adornment layer.

To define an adornment layer

In the Connector class declare a public field of type AdornmentLayerDefinition and export it with a NameAttribute that specifies a unique name for the adornment layer and a OrderAttribute that defines the Z-order relationship of this adornment layer to the other text view layers (text, caret, and selection).

<Export(GetType(AdornmentLayerDefinition)), Name("CommentAdornmentLayer"), Order(After:=PredefinedAdornmentLayers.Selection, Before:=PredefinedAdornmentLayers.Text)>
Public commentLayerDefinition As AdornmentLayerDefinition

[Export(typeof(AdornmentLayerDefinition))]
[Name("CommentAdornmentLayer")]
[Order(After = PredefinedAdornmentLayers.Selection, Before = PredefinedAdornmentLayers.Text)]
public AdornmentLayerDefinition commentLayerDefinition;

Providing Comment Adornments

When you define an adornment, also implement a comment adornment provider and a comment adornment manager. The comment adornment provider keeps a list of comment adornments, listens to Changed events on the underlying text buffer, and deletes comment adornments when the underlying text is deleted.

To add the comment adornment provider

Add a new class file to the CommentAdornmentTest project and name it CommentAdornmentProvider.

Add the following using statements.

Imports System
Imports System.Collections.Generic
Imports System.Collections.ObjectModel
Imports Microsoft.VisualStudio.Text
Imports Microsoft.VisualStudio.Text.Editor

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using Microsoft.VisualStudio.Text;
using Microsoft.VisualStudio.Text.Editor;

Add a class named CommentAdornmentProvider.

Friend Class CommentAdornmentProvider

internal class CommentAdornmentProvider

Add private fields for the text buffer and the list of comment adornments related to the buffer.

Private buffer As ITextBuffer
Private comments As IList(Of CommentAdornment) = New List(Of CommentAdornment)()

private ITextBuffer buffer;
private IList<CommentAdornment> comments = new List<CommentAdornment>();

Add a constructor for CommentAdornmentProvider. This constructor should have private access because the provider is instantiated by the Create() method. The constructor adds the OnBufferChanged event handler to the Changed event.

Private Sub New(ByVal buffer As ITextBuffer)
    Me.buffer = buffer
    'listen to the Changed event so we can react to deletions.
    AddHandler Me.buffer.Changed, AddressOf OnBufferChanged
End Sub

private CommentAdornmentProvider(ITextBuffer buffer)
{
    this.buffer = buffer;
    //listen to the Changed event so we can react to deletions.
    this.buffer.Changed += OnBufferChanged;
}

Add the Create() method.

Public Shared Function Create(ByVal view As IWpfTextView) As CommentAdornmentProvider
    Return view.Properties.GetOrCreateSingletonProperty(Of CommentAdornmentProvider)(Function() New CommentAdornmentProvider(view.TextBuffer))
End Function

public static CommentAdornmentProvider Create(IWpfTextView view)
{
    return view.Properties.GetOrCreateSingletonProperty<CommentAdornmentProvider>(delegate { return new CommentAdornmentProvider(view.TextBuffer); });
}

Add the Detach() method.

Public Sub Detach()
    If Me.buffer IsNot Nothing Then
        'remove the Changed listener
        RemoveHandler Me.buffer.Changed, AddressOf OnBufferChanged
        Me.buffer = Nothing
    End If
End Sub

public void Detach()
{
    if (this.buffer != null)
    {
        //remove the Changed listener
        this.buffer.Changed -= OnBufferChanged;
        this.buffer = null;
    }
}

Add the OnBufferChanged event handler.

Private Sub OnBufferChanged(ByVal sender As Object, ByVal e As TextContentChangedEventArgs)
    'Make a list of all comments that have a span of at least one character after applying the change. There is no need to raise a changed event for the deleted adornments. The adornments are deleted only if a text change would cause the view to reformat the line and discard the adornments.
    Dim keptComments As IList(Of CommentAdornment) = New List(Of CommentAdornment)(Me.comments.Count)

    For Each comment As CommentAdornment In Me.comments
        Dim span As Span = comment.Span.GetSpan(e.After)
        'if a comment does not span at least one character, its text was deleted.
        If span.Length <> 0 Then
            keptComments.Add(comment)
        End If
    Next comment

    Me.comments = keptComments
End Sub

private void OnBufferChanged(object sender, TextContentChangedEventArgs e)
{
    //Make a list of all comments that have a span of at least one character after applying the change. There is no need to raise a changed event for the deleted adornments. The adornments are deleted only if a text change would cause the view to reformat the line and discard the adornments.
    IList<CommentAdornment> keptComments = new List<CommentAdornment>(this.comments.Count);

    foreach (CommentAdornment comment in this.comments)
    {
        Span span = comment.Span.GetSpan(e.After);
        //if a comment does not span at least one character, its text was deleted.
        if (span.Length != 0)
        {
            keptComments.Add(comment);
        }
    }

    this.comments = keptComments;
}

Add a declaration for a CommentsChanged event.

Public Event CommentsChanged As EventHandler(Of CommentsChangedEventArgs)

public event EventHandler<CommentsChangedEventArgs> CommentsChanged;

Create an Add() method to add the adornment.

Public Sub Add(ByVal span As SnapshotSpan, ByVal author As String, ByVal text As String)
    If span.Length = 0 Then
        Throw New ArgumentOutOfRangeException("span")
    End If
    If author Is Nothing Then
        Throw New ArgumentNullException("author")
    End If
    If text Is Nothing Then
        Throw New ArgumentNullException("text")
    End If

    'Create a comment adornment given the span, author and text.
    Dim comment As New CommentAdornment(span, author, text)

    'Add it to the list of comments.
    Me.comments.Add(comment)

    'Raise the changed event.
    Dim commentsChanged As EventHandler(Of CommentsChangedEventArgs) = Me.CommentsChangedEvent
    If CommentsChangedEvent IsNot Nothing Then
        CommentsChangedEvent(Me, New CommentsChangedEventArgs(comment, Nothing))
    End If
End Sub

public void Add(SnapshotSpan span, string author, string text)
{
    if (span.Length == 0)
        throw new ArgumentOutOfRangeException("span");
    if (author == null)
        throw new ArgumentNullException("author");
    if (text == null)
        throw new ArgumentNullException("text");

    //Create a comment adornment given the span, author and text.
    CommentAdornment comment = new CommentAdornment(span, author, text);

    //Add it to the list of comments.
    this.comments.Add(comment);

    //Raise the changed event.
    EventHandler<CommentsChangedEventArgs> commentsChanged = this.CommentsChanged;
    if (commentsChanged != null)
        commentsChanged(this, new CommentsChangedEventArgs(comment, null));
}

Add a RemoveComments() method.

Public Sub RemoveComments(ByVal span As SnapshotSpan)
    Dim commentsChanged As EventHandler(Of CommentsChangedEventArgs) = Me.CommentsChangedEvent

    'Get a list of all the comments that are being kept 
    Dim keptComments As IList(Of CommentAdornment) = New List(Of CommentAdornment)(Me.comments.Count)

    For Each comment As CommentAdornment In Me.comments
        'find out if the given span overlaps with the comment text span. If two spans are adjacent, they do not overlap. To consider adjacent spans, use IntersectsWith.
        If comment.Span.GetSpan(span.Snapshot).OverlapsWith(span) Then
            'Raise the change event to delete this comment.
            If CommentsChangedEvent IsNot Nothing Then
                CommentsChangedEvent(Me, New CommentsChangedEventArgs(Nothing, comment))
            End If
        Else
            keptComments.Add(comment)
        End If
    Next comment

    Me.comments = keptComments
End Sub

public void RemoveComments(SnapshotSpan span)
{
    EventHandler<CommentsChangedEventArgs> commentsChanged = this.CommentsChanged;

    //Get a list of all the comments that are being kept 
    IList<CommentAdornment> keptComments = new List<CommentAdornment>(this.comments.Count);

    foreach (CommentAdornment comment in this.comments)
    {
        //find out if the given span overlaps with the comment text span. If two spans are adjacent, they do not overlap. To consider adjacent spans, use IntersectsWith.
        if (comment.Span.GetSpan(span.Snapshot).OverlapsWith(span))
        {
            //Raise the change event to delete this comment.
            if (commentsChanged != null)
                commentsChanged(this, new CommentsChangedEventArgs(null, comment));
        }
        else
            keptComments.Add(comment);
    }

    this.comments = keptComments;
}

Add a GetComments() method that returns all the comments in a given snapshot span.

Public Function GetComments(ByVal span As SnapshotSpan) As Collection(Of CommentAdornment)
    Dim overlappingComments As IList(Of CommentAdornment) = New List(Of CommentAdornment)()
    For Each comment As CommentAdornment In Me.comments
        If comment.Span.GetSpan(span.Snapshot).OverlapsWith(span) Then
            overlappingComments.Add(comment)
        End If
    Next comment

    Return New Collection(Of CommentAdornment)(overlappingComments)
End Function

public Collection<CommentAdornment> GetComments(SnapshotSpan span)
{
    IList<CommentAdornment> overlappingComments = new List<CommentAdornment>();
    foreach (CommentAdornment comment in this.comments)
    {
        if (comment.Span.GetSpan(span.Snapshot).OverlapsWith(span))
            overlappingComments.Add(comment);
    }

    return new Collection<CommentAdornment>(overlappingComments);
}

Add a class named CommentsChangedEventArgs, as follows.

Friend Class CommentsChangedEventArgs
    Inherits EventArgs
    Public ReadOnly CommentAdded As CommentAdornment
    Public ReadOnly CommentRemoved As CommentAdornment

    Public Sub New(ByVal added As CommentAdornment, ByVal removed As CommentAdornment)
        Me.CommentAdded = added
        Me.CommentRemoved = removed
    End Sub
End Class

internal class CommentsChangedEventArgs : EventArgs
{
    public readonly CommentAdornment CommentAdded;

    public readonly CommentAdornment CommentRemoved;

    public CommentsChangedEventArgs(CommentAdornment added, CommentAdornment removed)
    {
        this.CommentAdded = added;
        this.CommentRemoved = removed;
    }
}

Managing Comment Adornments

The comment adornment manager creates the adornment and adds it to the adornment layer. It listens to the LayoutChanged and Closed events so that it can move or delete the adornment. It also listens to the CommentsChanged event that is fired by the comment adornment provider when comments are added or removed.

To manage comment adornments

Add a class file to the CommentAdornmentTest project and name it CommentAdornmentManager.

Add the following using statements.

Imports System
Imports System.Collections.Generic
Imports System.Windows.Media
Imports Microsoft.VisualStudio.Text
Imports Microsoft.VisualStudio.Text.Editor
Imports Microsoft.VisualStudio.Text.Formatting

using System;
using System.Collections.Generic;
using System.Windows.Media;
using Microsoft.VisualStudio.Text;
using Microsoft.VisualStudio.Text.Editor;
using Microsoft.VisualStudio.Text.Formatting;

Add a class named CommentAdornmentManager.

Friend Class CommentAdornmentManager

internal class CommentAdornmentManager

Add some private fields.

Private ReadOnly view As IWpfTextView
Private ReadOnly layer As IAdornmentLayer
Private ReadOnly provider As CommentAdornmentProvider

private readonly IWpfTextView view;
private readonly IAdornmentLayer layer;
private readonly CommentAdornmentProvider provider;

Add a constructor that subscribes the manager to the LayoutChanged and Closed events, and also to the CommentsChanged event. The constructor is private because the manager is instantiated by the static Create() method.

Private Sub New(ByVal view As IWpfTextView)
    Me.view = view
    AddHandler Me.view.LayoutChanged, AddressOf OnLayoutChanged
    AddHandler Me.view.Closed, AddressOf OnClosed

    Me.layer = view.GetAdornmentLayer("CommentAdornmentLayer")

    Me.provider = CommentAdornmentProvider.Create(view)
    AddHandler Me.provider.CommentsChanged, AddressOf OnCommentsChanged
End Sub

private CommentAdornmentManager(IWpfTextView view)
{
    this.view = view;
    this.view.LayoutChanged += OnLayoutChanged;
    this.view.Closed += OnClosed;

    this.layer = view.GetAdornmentLayer("CommentAdornmentLayer");

    this.provider = CommentAdornmentProvider.Create(view);
    this.provider.CommentsChanged += OnCommentsChanged;
}

Add the Create() method that gets a provider or creates one if required.

Public Shared Function Create(ByVal view As IWpfTextView) As CommentAdornmentManager
    Return view.Properties.GetOrCreateSingletonProperty(Of CommentAdornmentManager)(Function() New CommentAdornmentManager(view))
End Function

public static CommentAdornmentManager Create(IWpfTextView view)
{
    return view.Properties.GetOrCreateSingletonProperty<CommentAdornmentManager>(delegate { return new CommentAdornmentManager(view); });
}

Add the CommentsChanged handler.

Private Sub OnCommentsChanged(ByVal sender As Object, ByVal e As CommentsChangedEventArgs)
    'Remove the comment (when the adornment was added, the comment adornment was used as the tag).
    If e.CommentRemoved IsNot Nothing Then
        Me.layer.RemoveAdornmentsByTag(e.CommentRemoved)
    End If

    'Draw the newly added comment (this will appear immediately: the view does not need to do a layout).
    If e.CommentAdded IsNot Nothing Then
        Me.DrawComment(e.CommentAdded)
    End If
End Sub

private void OnCommentsChanged(object sender, CommentsChangedEventArgs e)
{
    //Remove the comment (when the adornment was added, the comment adornment was used as the tag).
    if (e.CommentRemoved != null)
        this.layer.RemoveAdornmentsByTag(e.CommentRemoved);

    //Draw the newly added comment (this will appear immediately: the view does not need to do a layout).
    if (e.CommentAdded != null)
        this.DrawComment(e.CommentAdded);
}

Add the Closed handler.

Private Sub OnClosed(ByVal sender As Object, ByVal e As EventArgs)
    Me.provider.Detach()
    RemoveHandler Me.view.LayoutChanged, AddressOf OnLayoutChanged
    RemoveHandler Me.view.Closed, AddressOf OnClosed
End Sub

private void OnClosed(object sender, EventArgs e)
{
    this.provider.Detach();
    this.view.LayoutChanged -= OnLayoutChanged;
    this.view.Closed -= OnClosed;
}

Add the LayoutChanged handler.

Private Sub OnLayoutChanged(ByVal sender As Object, ByVal e As TextViewLayoutChangedEventArgs)
    'Get all of the comments that intersect any of the new or reformatted lines of text.
    Dim newComments As New List(Of CommentAdornment)()

    'The event args contain a list of modified lines and a NormalizedSpanCollection of the spans of the modified lines. 
    'Use the latter to find the comments that intersect the new or reformatted lines of text.
    For Each span As Span In e.NewOrReformattedSpans
        newComments.AddRange(Me.provider.GetComments(New SnapshotSpan(Me.view.TextSnapshot, span)))
    Next span

    'It is possible to get duplicates in this list if a comment spanned 3 lines, and the first and last lines were modified but the middle line was not.
    'Sort the list and skip duplicates.
    newComments.Sort(Function(a As CommentAdornment, b As CommentAdornment) a.GetHashCode().CompareTo(b.GetHashCode()))

    Dim lastComment As CommentAdornment = Nothing
    For Each comment As CommentAdornment In newComments
        If comment IsNot lastComment Then
            lastComment = comment
            Me.DrawComment(comment)
        End If
    Next comment
End Sub

private void OnLayoutChanged(object sender, TextViewLayoutChangedEventArgs e)
{
    //Get all of the comments that intersect any of the new or reformatted lines of text.
    List<CommentAdornment> newComments = new List<CommentAdornment>();

    //The event args contain a list of modified lines and a NormalizedSpanCollection of the spans of the modified lines. 
    //Use the latter to find the comments that intersect the new or reformatted lines of text.
    foreach (Span span in e.NewOrReformattedSpans)
    {
        newComments.AddRange(this.provider.GetComments(new SnapshotSpan(this.view.TextSnapshot, span)));
    }

    //It is possible to get duplicates in this list if a comment spanned 3 lines, and the first and last lines were modified but the middle line was not.
    //Sort the list and skip duplicates.
    newComments.Sort(delegate(CommentAdornment a, CommentAdornment b) { return a.GetHashCode().CompareTo(b.GetHashCode()); });

    CommentAdornment lastComment = null;
    foreach (CommentAdornment comment in newComments)
    {
        if (comment != lastComment)
        {
            lastComment = comment;
            this.DrawComment(comment);
        }
    }
}

Add the private method that draws the comment.

Private Sub DrawComment(ByVal comment As CommentAdornment)
    Dim span As SnapshotSpan = comment.Span.GetSpan(Me.view.TextSnapshot)
    Dim g As Geometry = Me.view.TextViewLines.GetMarkerGeometry(span)

    If g IsNot Nothing Then
        'Find the rightmost coordinate of all the lines that intersect the adornment.
        Dim maxRight As Double = 0.0
        For Each line As ITextViewLine In Me.view.TextViewLines.GetTextViewLinesIntersectingSpan(span)
            maxRight = Math.Max(maxRight, line.Right)
        Next line

        'Create the visualization.
        Dim block As New CommentBlock(maxRight, Me.view.ViewportRight, g, comment.Author, comment.Text)

        'Add it to the layer.
        Me.layer.AddAdornment(span, comment, block)
    End If
End Sub

private void DrawComment(CommentAdornment comment)
{
    SnapshotSpan span = comment.Span.GetSpan(this.view.TextSnapshot);
    Geometry g = this.view.TextViewLines.GetMarkerGeometry(span);

    if (g != null)
    {
        //Find the rightmost coordinate of all the lines that intersect the adornment.
        double maxRight = 0.0;
        foreach (ITextViewLine line in this.view.TextViewLines.GetTextViewLinesIntersectingSpan(span))
            maxRight = Math.Max(maxRight, line.Right);

        //Create the visualization.
        CommentBlock block = new CommentBlock(maxRight, this.view.ViewportRight, g, comment.Author, comment.Text);

        //Add it to the layer.
        this.layer.AddAdornment(span, comment, block);
    }
}

You can use the menu command to create a comment adornment by implementing the MenuItemCallback method of the VSPackage.

Add the following references to the MenuCommandTest project:
- Microsoft.VisualStudio.TextManager.Interop
- Microsoft.VisualStudio.Editor
- Microsoft.VisualStudio.Text.UI.Wpf
Add a reference to the CommentAdornmentTest project.
Open the MenuCommandTestPackage file.

Add the following using statements.

Imports Microsoft.VisualStudio.TextManager.Interop
Imports Microsoft.VisualStudio.Text.Editor
Imports Microsoft.VisualStudio.Editor
Imports CommentAdornmentTest

using Microsoft.VisualStudio.TextManager.Interop;
using Microsoft.VisualStudio.Text.Editor;
using Microsoft.VisualStudio.Editor;
using CommentAdornmentTest;

In the MenuItemCallback method, remove the existing code.

Add code to get the active view. You must get the SVsTextManager of the Visual Studio shell to get the active IVsTextView.

Dim txtMgr As IVsTextManager = CType(GetService(GetType(SVsTextManager)), IVsTextManager)
Dim vTextView As IVsTextView = Nothing
Dim mustHaveFocus As Integer = 1
txtMgr.GetActiveView(mustHaveFocus, Nothing, vTextView)

IVsTextManager txtMgr = (IVsTextManager)GetService(typeof(SVsTextManager));
IVsTextView vTextView = null;
int mustHaveFocus = 1;
txtMgr.GetActiveView(mustHaveFocus, null, out vTextView);

If this text view is an instance of an editor text view, you can cast it to the IVsUserData interface and then get the IWpfTextViewHost and its associated IWpfTextView.

Dim userData As IVsUserData = TryCast(vTextView, IVsUserData)
If userData Is Nothing Then
    Console.WriteLine("No text view is currently open")
    Return
End If
Dim viewHost As IWpfTextViewHost
Dim holder As Object
Dim guidViewHost As Guid = DefGuidList.guidIWpfTextViewHost
userData.GetData(guidViewHost, holder)
viewHost = CType(holder, IWpfTextViewHost)

IVsUserData userData = vTextView as IVsUserData;
if (userData == null)
{
    Console.WriteLine("No text view is currently open");
    return;
}
IWpfTextViewHost viewHost;
object holder;
Guid guidViewHost = DefGuidList.guidIWpfTextViewHost;
userData.GetData(ref guidViewHost, out holder);
viewHost = (IWpfTextViewHost)holder;

Use the IWpfTextViewHost to call the Connector.Execute() method, which gets the comment adornment provider and adds the adornment.
```
Connector.Execute(viewHost)
```
```
Connector.Execute(viewHost);
```

Building and Testing the Code

To test this code, build the MenuCommand solution and run it in the experimental instance.

To build and test the MenuCommand solution

Build the solution. When you run this project in the debugger, a second instance of Visual Studio is instantiated.
Create a text file. Type some text and then select it.
On the Tools menu, click Add Adornment. A balloon should be displayed on the right side of the text window, and should contain text that resembles the following text.

YourUserName

Fourscore…

Walkthrough: Using a Shell Command with an Editor Extension

Prerequisites

Locations for the Visual Studio Package Project Template

Creating a Menu Command VSPackage

To create a menu command VSPackage

Adding a MEF Extension to the VSPackage Solution

To add the MEF extension to the VSPackage solution

Referring to the MEF Extension in the VSPackage Project

To refer to the MEF component in the VSPackage project

Defining a Comment Adornment

To define a comment adornment

Creating a Visual Element for the Adornment

To create a visual element for the adornment

Adding an IWpfTextViewCreationListener

To add an IWpfTextViewCreationListener

Defining an Adornment Layer

To define an adornment layer

Providing Comment Adornments

To add the comment adornment provider

Managing Comment Adornments

To manage comment adornments

Using the Menu Command to Add the Comment Adornment

To use the menu command to add the comment adornment

Building and Testing the Code

To build and test the MenuCommand solution

See Also

Tasks

Additional resources