演练:显示文本

2015-05-18

可以将不同的视觉效果编辑器通过创建 managed extensibility framework 组件。 (MEF) 本演练演示了如何显示当前单词的每次出现在文本文件中。如果运行发生以上的文本文件的一次，，并确定在一个匹配项的插入符号，每个匹配项显示。

系统必备

若要完成本演练，您必须安装 Visual Studio 2010 SDK。

备注

有关 Visual Studio SDK 的更多信息，请参见扩展 Visual Studio 概述。若要查找有关中所列如何下载 Visual Studio SDK，请 Visual Studio Extensibility Developer Center 参见 MSDN 网站上。

创建 MEF 项目

创建一个编辑分类器项目。将解决方案命名为 HighlightWordTest。
打开在 VSIX 清单编辑器中的 source.extension.vsixmanifest 文件。
确保 Content 归为包含一个 MEF 组件内容类型，而 Path 设置为 HighlightWordTest.dll。
保存并关闭的 source.extension.vsixmanifest。
删除现有类文件。

定义 TextMarkerTag

在显示文本的第一步是子类 TextMarkerTag 并定义其外观。

定义 TextMarkerTag 和 MarkerFormatDefinition

将类文件并将其命名为 HighlightWordTag。

导入下列命名空间。

Imports System
Imports System.Collections.Generic
Imports System.ComponentModel.Composition
Imports System.Linq
Imports System.Threading
Imports System.Windows.Media
Imports Microsoft.VisualStudio.Text
Imports Microsoft.VisualStudio.Text.Classification
Imports Microsoft.VisualStudio.Text.Editor
Imports Microsoft.VisualStudio.Text.Operations
Imports Microsoft.VisualStudio.Text.Tagging
Imports Microsoft.VisualStudio.Utilities

using System;
using System.Collections.Generic;
using System.ComponentModel.Composition;
using System.Linq;
using System.Threading;
using System.Windows.Media;
using Microsoft.VisualStudio.Text;
using Microsoft.VisualStudio.Text.Classification;
using Microsoft.VisualStudio.Text.Editor;
using Microsoft.VisualStudio.Text.Operations;
using Microsoft.VisualStudio.Text.Tagging;
using Microsoft.VisualStudio.Utilities;

创建从 TextMarkerTag 继承的类并将其命名为 HighlightWordTag。

Friend Class HighlightWordTag
    Inherits TextMarkerTag

internal class HighlightWordTag : TextMarkerTag

创建从 MarkerFormatDefinition继承的第二个类，并将其命名为 HighlightWordFormatDefinition。为了为标记使用此格式定义，必须导出它具有以下属性:

NameAttribute:标记使用此引用此格式
UserVisibleAttribute:这使得格式显示在 UI

<Export(GetType(EditorFormatDefinition))>
<Name("MarkerFormatDefinition/HighlightWordFormatDefinition")>
<UserVisible(True)>
Friend Class HighlightWordFormatDefinition
    Inherits MarkerFormatDefinition

[Export(typeof(EditorFormatDefinition))]
[Name("MarkerFormatDefinition/HighlightWordFormatDefinition")]
[UserVisible(true)]
internal class HighlightWordFormatDefinition : MarkerFormatDefinition

在 HighlightWordFormatDefinition 的构造函数中，定义其显示名称和外观。，而前景属性定义边框颜色，背景属性定义填充颜色。

Public Sub New()
    Me.BackgroundColor = Colors.LightBlue
    Me.ForegroundColor = Colors.DarkBlue
    Me.DisplayName = "Highlight Word" 
    Me.ZOrder = 5
End Sub

public HighlightWordFormatDefinition()
{
    this.BackgroundColor = Colors.LightBlue;
    this.ForegroundColor = Colors.DarkBlue;
    this.DisplayName = "Highlight Word";
    this.ZOrder = 5;
}

在 HighlightWordTag 的构造函数，请在您创建的格式定义的名称。

Public Sub New()
    MyBase.New("MarkerFormatDefinition/HighlightWordFormatDefinition")
End Sub

public HighlightWordTag() : base("MarkerFormatDefinition/HighlightWordFormatDefinition") { }

实现 ITagger

下一步是实现 ITagger 接口。此接口分配，以提供显示文本的给定文本缓冲区、标记和其他可视化效果。

实现标记

创建实现类型 HighlightWordTagITagger 的类，并将其命名为 HighlightWordTagger。

Friend Class HighlightWordTagger
    Implements ITagger(Of HighlightWordTag)

internal class HighlightWordTagger : ITagger<HighlightWordTag>

添加以下私有字段和属性添加到类:

ITextView，对应于当前文本视图。
ITextBuffer，对应于文本缓冲区基础文本视图。
ITextSearchService，用于查找文本。
ITextStructureNavigator，具有导航的方法在文本范围内。
NormalizedSnapshotSpanCollection，其中包含用来运行显示。
SnapshotSpan，对应于当前字。
SnapshotPoint，对应于插入符号的当前位置。
锁定对象。

Private _View As ITextView
Private Property View() As ITextView
    Get 
        Return _View
    End Get 
    Set(ByVal value As ITextView)
        _View = value
    End Set 
End Property 
Private _SourceBuffer As ITextBuffer
Private Property SourceBuffer() As ITextBuffer
    Get 
        Return _SourceBuffer
    End Get 
    Set(ByVal value As ITextBuffer)
        _SourceBuffer = value
    End Set 
End Property 
Private _TextSearchService As ITextSearchService
Private Property TextSearchService() As ITextSearchService
    Get 
        Return _TextSearchService
    End Get 
    Set(ByVal value As ITextSearchService)
        _TextSearchService = value
    End Set 
End Property 
Private _TextStructureNavigator As ITextStructureNavigator
Private Property TextStructureNavigator() As ITextStructureNavigator
    Get 
        Return _TextStructureNavigator
    End Get 
    Set(ByVal value As ITextStructureNavigator)
        _TextStructureNavigator = value
    End Set 
End Property 
Private _WordSpans As NormalizedSnapshotSpanCollection
Private Property WordSpans() As NormalizedSnapshotSpanCollection
    Get 
        Return _WordSpans
    End Get 
    Set(ByVal value As NormalizedSnapshotSpanCollection)
        _WordSpans = value
    End Set 
End Property 
Private _CurrentWord As System.Nullable(Of SnapshotSpan)
Private Property CurrentWord() As System.Nullable(Of SnapshotSpan)
    Get 
        Return _CurrentWord
    End Get 
    Set(ByVal value As System.Nullable(Of SnapshotSpan))
        _CurrentWord = value
    End Set 
End Property 
Private _RequestedPoint As SnapshotPoint
Private Property RequestedPoint() As SnapshotPoint
    Get 
        Return _RequestedPoint
    End Get 
    Set(ByVal value As SnapshotPoint)
        _RequestedPoint = value
    End Set 
End Property 
Private updateLock As New Object()

ITextView View { get; set; }
ITextBuffer SourceBuffer { get; set; }
ITextSearchService TextSearchService { get; set; }
ITextStructureNavigator TextStructureNavigator { get; set; }
NormalizedSnapshotSpanCollection WordSpans { get; set; }
SnapshotSpan? CurrentWord { get; set; }
SnapshotPoint RequestedPoint { get; set; }
object updateLock = new object();

添加初始化前面列出的属性并添加 LayoutChanged 和 PositionChanged 事件处理程序的构造函数。

Public Sub New(ByVal view As ITextView, ByVal sourceBuffer As ITextBuffer, ByVal textSearchService As ITextSearchService, ByVal textStructureNavigator As ITextStructureNavigator)
    Me.View = view
    Me.SourceBuffer = sourceBuffer
    Me.TextSearchService = textSearchService
    Me.TextStructureNavigator = textStructureNavigator
    Me.WordSpans = New NormalizedSnapshotSpanCollection()
    Me.CurrentWord = Nothing 
    AddHandler Me.View.Caret.PositionChanged, AddressOf CaretPositionChanged
    AddHandler Me.View.LayoutChanged, AddressOf ViewLayoutChanged
End Sub

public HighlightWordTagger(ITextView view, ITextBuffer sourceBuffer, ITextSearchService textSearchService,
ITextStructureNavigator textStructureNavigator)
{
    this.View = view;
    this.SourceBuffer = sourceBuffer;
    this.TextSearchService = textSearchService;
    this.TextStructureNavigator = textStructureNavigator;
    this.WordSpans = new NormalizedSnapshotSpanCollection();
    this.CurrentWord = null;
    this.View.Caret.PositionChanged += CaretPositionChanged;
    this.View.LayoutChanged += ViewLayoutChanged;
}

事件处理程序的两个调用 UpdateAtCaretPosition 方法。

Private Sub ViewLayoutChanged(ByVal sender As Object, ByVal e As TextViewLayoutChangedEventArgs)
    ' If a new snapshot wasn't generated, then skip this layout 
    If e.NewSnapshot IsNot e.OldSnapshot Then
        UpdateAtCaretPosition(View.Caret.Position)
    End If 
End Sub 

Private Sub CaretPositionChanged(ByVal sender As Object, ByVal e As CaretPositionChangedEventArgs)
    UpdateAtCaretPosition(e.NewPosition)
End Sub

void ViewLayoutChanged(object sender, TextViewLayoutChangedEventArgs e)
{
    // If a new snapshot wasn't generated, then skip this layout 
    if (e.NewSnapshot != e.OldSnapshot)
    {
        UpdateAtCaretPosition(View.Caret.Position);
    }
}

void CaretPositionChanged(object sender, CaretPositionChangedEventArgs e)
{
    UpdateAtCaretPosition(e.NewPosition);
}

您还必须将将通过更新方法调用的 TagsChanged 事件。

Public Event TagsChanged(ByVal sender As Object, ByVal e As SnapshotSpanEventArgs) _
    Implements ITagger(Of HighlightWordTag).TagsChanged

public event EventHandler<SnapshotSpanEventArgs> TagsChanged;

UpdateAtCaretPosition() 方法查找与运行相同的光标定位和构造列表 SnapshotSpan 对象对应于单词的匹配项的文本缓冲区中的每个单词。然后调用 SynchronousUpdate，将引发 TagsChanged 事件。

Private Sub UpdateAtCaretPosition(ByVal caretPosition As CaretPosition)
    Dim point As System.Nullable(Of SnapshotPoint) = caretPosition.Point.GetPoint(SourceBuffer, caretPosition.Affinity)

    If Not point.HasValue Then 
        Exit Sub 
    End If 

    ' If the new caret position is still within the current word (and on the same snapshot), we don't need to check it 
    If CurrentWord.HasValue AndAlso CurrentWord.Value.Snapshot Is View.TextSnapshot AndAlso point.Value > CurrentWord.Value.Start AndAlso point.Value < CurrentWord.Value.[End] Then 
        Exit Sub 
    End If

    RequestedPoint = point.Value
    UpdateWordAdornments()
End Sub 

Private Sub UpdateWordAdornments()
    Dim currentRequest As SnapshotPoint = RequestedPoint
    Dim wordSpans As New List(Of SnapshotSpan)()
    'Find all words in the buffer like the one the caret is on 
    Dim word As TextExtent = TextStructureNavigator.GetExtentOfWord(currentRequest)
    Dim foundWord As Boolean = True 
    'If we've selected something not worth highlighting, we might have missed a "word" by a little bit 
    If Not WordExtentIsValid(currentRequest, word) Then 
        'Before we retry, make sure it is worthwhile 
        If word.Span.Start <> currentRequest OrElse currentRequest = currentRequest.GetContainingLine().Start OrElse Char.IsWhiteSpace((currentRequest - 1).GetChar()) Then
            foundWord = False 
        Else 
            ' Try again, one character previous.  
            'If the caret is at the end of a word, pick up the word.
            word = TextStructureNavigator.GetExtentOfWord(currentRequest - 1)

            'If the word still isn't valid, we're done 
            If Not WordExtentIsValid(currentRequest, word) Then
                foundWord = False 
            End If 
        End If 
    End If 

    If Not foundWord Then 
        'If we couldn't find a word, clear out the existing markers
        SynchronousUpdate(currentRequest, New NormalizedSnapshotSpanCollection(), Nothing)
        Exit Sub 
    End If 

    Dim currentWord__1 As SnapshotSpan = word.Span
    'If this is the current word, and the caret moved within a word, we're done. 
    If CurrentWord.HasValue AndAlso currentWord__1 = CurrentWord Then 
        Exit Sub 
    End If 

    'Find the new spans 
    Dim findData As New FindData(currentWord__1.GetText(), currentWord__1.Snapshot)
    findData.FindOptions = FindOptions.WholeWord Or FindOptions.MatchCase

    wordSpans.AddRange(TextSearchService.FindAll(findData))

    'If another change hasn't happened, do a real update 
    If currentRequest = RequestedPoint Then
        SynchronousUpdate(currentRequest, New NormalizedSnapshotSpanCollection(wordSpans), currentWord__1)
    End If 
End Sub 
Private Shared Function WordExtentIsValid(ByVal currentRequest As SnapshotPoint, ByVal word As TextExtent) As Boolean 
    Return word.IsSignificant AndAlso currentRequest.Snapshot.GetText(word.Span).Any(Function(c) Char.IsLetter(c))
End Function

void UpdateAtCaretPosition(CaretPosition caretPosition)
{
    SnapshotPoint? point = caretPosition.Point.GetPoint(SourceBuffer, caretPosition.Affinity);

    if (!point.HasValue)
        return;

    // If the new caret position is still within the current word (and on the same snapshot), we don't need to check it 
    if (CurrentWord.HasValue
        && CurrentWord.Value.Snapshot == View.TextSnapshot
        && point.Value >= CurrentWord.Value.Start
        && point.Value <= CurrentWord.Value.End)
    {
        return;
    }

    RequestedPoint = point.Value;
    UpdateWordAdornments();
}

void UpdateWordAdornments()
{
    SnapshotPoint currentRequest = RequestedPoint;
    List<SnapshotSpan> wordSpans = new List<SnapshotSpan>();
    //Find all words in the buffer like the one the caret is on
    TextExtent word = TextStructureNavigator.GetExtentOfWord(currentRequest);
    bool foundWord = true;
    //If we've selected something not worth highlighting, we might have missed a "word" by a little bit
    if (!WordExtentIsValid(currentRequest, word))
    {
        //Before we retry, make sure it is worthwhile 
        if (word.Span.Start != currentRequest
             || currentRequest == currentRequest.GetContainingLine().Start
             || char.IsWhiteSpace((currentRequest - 1).GetChar()))
        {
            foundWord = false;
        }
        else
        {
            // Try again, one character previous.  
            //If the caret is at the end of a word, pick up the word.
            word = TextStructureNavigator.GetExtentOfWord(currentRequest - 1);

            //If the word still isn't valid, we're done 
            if (!WordExtentIsValid(currentRequest, word))
                foundWord = false;
        }
    }

    if (!foundWord)
    {
        //If we couldn't find a word, clear out the existing markers
        SynchronousUpdate(currentRequest, new NormalizedSnapshotSpanCollection(), null);
        return;
    }

    SnapshotSpan currentWord = word.Span;
    //If this is the current word, and the caret moved within a word, we're done. 
    if (CurrentWord.HasValue && currentWord == CurrentWord)
        return;

    //Find the new spans
    FindData findData = new FindData(currentWord.GetText(), currentWord.Snapshot);
    findData.FindOptions = FindOptions.WholeWord | FindOptions.MatchCase;

    wordSpans.AddRange(TextSearchService.FindAll(findData));

    //If another change hasn't happened, do a real update 
    if (currentRequest == RequestedPoint)
        SynchronousUpdate(currentRequest, new NormalizedSnapshotSpanCollection(wordSpans), currentWord);
}
static bool WordExtentIsValid(SnapshotPoint currentRequest, TextExtent word)
{
    return word.IsSignificant
        && currentRequest.Snapshot.GetText(word.Span).Any(c => char.IsLetter(c));
}

SynchronousUpdate 执行在 WordSpans 和 CurrentWord 属性的一次同步更新，并引发 TagsChanged 事件。

Private Sub SynchronousUpdate(ByVal currentRequest As SnapshotPoint, ByVal newSpans As NormalizedSnapshotSpanCollection, ByVal newCurrentWord As System.Nullable(Of SnapshotSpan))
    SyncLock updateLock
        If currentRequest <> RequestedPoint Then 
            Exit Sub 
        End If

        WordSpans = newSpans
        CurrentWord = newCurrentWord

        RaiseEvent TagsChanged(Me, New SnapshotSpanEventArgs(New SnapshotSpan(SourceBuffer.CurrentSnapshot, 0, SourceBuffer.CurrentSnapshot.Length)))
    End SyncLock 
End Sub

void SynchronousUpdate(SnapshotPoint currentRequest, NormalizedSnapshotSpanCollection newSpans, SnapshotSpan? newCurrentWord)
{
    lock (updateLock)
    {
        if (currentRequest != RequestedPoint)
            return;

        WordSpans = newSpans;
        CurrentWord = newCurrentWord;

        var tempEvent = TagsChanged;
        if (tempEvent != null)
            tempEvent(this, new SnapshotSpanEventArgs(new SnapshotSpan(SourceBuffer.CurrentSnapshot, 0, SourceBuffer.CurrentSnapshot.Length)));
    }
}

必须执行 GetTags 方法。此方法将 SnapshotSpan 对象的集合并返回标记范围的枚举。

在 c# 中，将执行此方法作为生成迭代器，启用延迟计算 (即计算，仅当各个项已捕获) 时标记。在 Visual Basic 中，添加标记到列表中并返回列表。

此处方法返回具有 “blue” TextMarkerTag，提供蓝色背景的 TagSpan 对象。

Public Function GetTags(ByVal spans As NormalizedSnapshotSpanCollection) As IEnumerable(Of ITagSpan(Of HighlightWordTag)) Implements ITagger(Of HighlightWordTag).GetTags
    If CurrentWord Is Nothing Then 
        Return Nothing 
        Exit Function 
    End If 

    ' Hold on to a "snapshot" of the word spans and current word, so that we maintain the same 
    ' collection throughout 
    Dim currentWord__1 As SnapshotSpan = CurrentWord.Value
    Dim wordSpans__2 As NormalizedSnapshotSpanCollection = WordSpans

    If spans.Count = 0 OrElse WordSpans.Count = 0 Then 
        Return Nothing 
        Exit Function 
    End If 

    ' If the requested snapshot isn't the same as the one our words are on, translate our spans to the expected snapshot 
    If spans(0).Snapshot IsNot wordSpans__2(0).Snapshot Then
        wordSpans__2 = New NormalizedSnapshotSpanCollection(wordSpans__2.[Select](Function(span) span.TranslateTo(spans(0).Snapshot, SpanTrackingMode.EdgeExclusive)))

        currentWord__1 = currentWord__1.TranslateTo(spans(0).Snapshot, SpanTrackingMode.EdgeExclusive)
    End If 
    'in order to emulate the C# yield return functionality, 
    'create a list and add all the relevant spans to it, then return the list 
    Dim list As List(Of TagSpan(Of HighlightWordTag))
    list = New List(Of TagSpan(Of HighlightWordTag))()

    If spans.OverlapsWith(New NormalizedSnapshotSpanCollection(currentWord__1)) Then
        list.Add(New TagSpan(Of HighlightWordTag)(CurrentWord, New HighlightWordTag()))
    End If 

    For Each span As SnapshotSpan In NormalizedSnapshotSpanCollection.Overlap(spans, wordSpans__2)
        list.Add(New TagSpan(Of HighlightWordTag)(span, New HighlightWordTag()))
    Next 
    Return List
End Function

public IEnumerable<ITagSpan<HighlightWordTag>> GetTags(NormalizedSnapshotSpanCollection spans)
{
    if (CurrentWord == null)
        yield break;

    // Hold on to a "snapshot" of the word spans and current word, so that we maintain the same
    // collection throughout
    SnapshotSpan currentWord = CurrentWord.Value;
    NormalizedSnapshotSpanCollection wordSpans = WordSpans;

    if (spans.Count == 0 || wordSpans.Count == 0)
        yield break;

    // If the requested snapshot isn't the same as the one our words are on, translate our spans to the expected snapshot 
    if (spans[0].Snapshot != wordSpans[0].Snapshot)
    {
        wordSpans = new NormalizedSnapshotSpanCollection(
            wordSpans.Select(span => span.TranslateTo(spans[0].Snapshot, SpanTrackingMode.EdgeExclusive)));

        currentWord = currentWord.TranslateTo(spans[0].Snapshot, SpanTrackingMode.EdgeExclusive);
    }

    // First, yield back the word the cursor is under (if it overlaps) 
    // Note that we'll yield back the same word again in the wordspans collection; 
    // the duplication here is expected. 
    if (spans.OverlapsWith(new NormalizedSnapshotSpanCollection(currentWord)))
        yield return new TagSpan<HighlightWordTag>(currentWord, new HighlightWordTag());

    // Second, yield all the other words in the file 
    foreach (SnapshotSpan span in NormalizedSnapshotSpanCollection.Overlap(spans, wordSpans))
    {
        yield return new TagSpan<HighlightWordTag>(span, new HighlightWordTag());
    }
}

创建标记提供程序

若要创建该标记，则必须实现 IViewTaggerProvider。此类是 MEF 组件部件，因此，必须设置正确的属性，以便此扩展由识别。

备注

有关 MEF 的更多信息，请参见 Managed Extensibility Framework (MEF)。

创建标记提供程序

创建实现 IViewTaggerProvider名为 HighlightWordTaggerProvider 的类，并将其导出与 “text” ContentTypeAttribute 和 TextMarkerTag TagTypeAttribute 。

<Export(GetType(IViewTaggerProvider))>
<ContentType("text")>
<TagType(GetType(TextMarkerTag))>
Friend Class HighlightWordTaggerProvider
    Implements IViewTaggerProvider

[Export(typeof(IViewTaggerProvider))]
[ContentType("text")]
[TagType(typeof(TextMarkerTag))]
internal class HighlightWordTaggerProvider : IViewTaggerProvider

必须导入两个编辑服务， ITextSearchService 和 ITextStructureNavigatorSelectorService，将实例化标记。

Private _TextSearchService As ITextSearchService
<Import()> _
Friend Property TextSearchService() As ITextSearchService
    Get 
        Return _TextSearchService
    End Get 
    Set(ByVal value As ITextSearchService)
        _TextSearchService = value
    End Set 
End Property 

Private _TextStructureNavigatorSelector As ITextStructureNavigatorSelectorService
<Import()>
Friend Property TextStructureNavigatorSelector() As ITextStructureNavigatorSelectorService
    Get 
        Return _TextStructureNavigatorSelector
    End Get 
    Set(ByVal value As ITextStructureNavigatorSelectorService)
        _TextStructureNavigatorSelector = value
    End Set 
End Property

[Import]
internal ITextSearchService TextSearchService { get; set; }

[Import]
internal ITextStructureNavigatorSelectorService TextStructureNavigatorSelector { get; set; }

执行 CreateTagger``1 方法返回 HighlightWordTagger实例。

Public Function CreateTagger(Of T As ITag)(ByVal textView As ITextView, ByVal buffer As ITextBuffer) As ITagger(Of T) Implements IViewTaggerProvider.CreateTagger
    'provide highlighting only on the top buffer 
    If textView.TextBuffer IsNot buffer Then 
        Return Nothing 
    End If 

    Dim textStructureNavigator As ITextStructureNavigator = TextStructureNavigatorSelector.GetTextStructureNavigator(buffer)

    Return TryCast(New HighlightWordTagger(textView, buffer, TextSearchService, textStructureNavigator), ITagger(Of T))
End Function

public ITagger<T> CreateTagger<T>(ITextView textView, ITextBuffer buffer) where T : ITag
{
    //provide highlighting only on the top buffer 
    if (textView.TextBuffer != buffer)
        return null;

    ITextStructureNavigator textStructureNavigator =
        TextStructureNavigatorSelector.GetTextStructureNavigator(buffer);

    return new HighlightWordTagger(textView, buffer, TextSearchService, textStructureNavigator) as ITagger<T>;
}

生成并测试代码

若要测试此代码，请生成 HighlightWordTest 解决方案并运行在的实验实例。

生成和测试 HighlightWordTest 解决方案

生成解决方案。
当您运行在调试器中查看此项目， Visual Studio 的第二个实例进行实例化。
创建一个文本文件并键入单词重复，例如， “hello " hello " hello”的某些文本。
将光标放在一个匹配项中 “hello”。在蓝色应显示每个匹配项。

请参见

任务

演练:链接到文件扩展名的内容类型

通过

演练:显示文本

系统必备

创建 MEF 项目

创建 MEF 项目

定义 TextMarkerTag

定义 TextMarkerTag 和 MarkerFormatDefinition

实现 ITagger

实现标记

创建标记提供程序

创建标记提供程序

生成并测试代码

生成和测试 HighlightWordTest 解决方案

请参见

任务

其他资源