逐步解說：顯示對稱的括號

發行項
05/16/2015

您可以實作語言為基礎的功能，例如括號來定義您要比對，大括的號，以及當插入號位於其中一個大括號，然後將文字標記標籤新增至對稱的括號對稱。您可以定義大括號內的一種語言，您可以定義您自己的檔案名稱副檔名和內容類型，並將標籤套用到只是該型別，或是您可以將標籤套用到現有的內容類型 (例如，"text")。下列逐步解說會示範如何套用括號對稱的「文字」的內容類型的標籤。

必要條件

若要完成這個逐步解說中，您必須安裝Visual Studio 2010 SDK。

注意事項
如需有關 Visual Studio 的 SDK 的詳細資訊，請參閱擴充 Visual Studio 的概觀。若要了解如何下載 Visual Studio 的 SDK，請參閱Visual Studio 擴充性開發人員中心 MSDN 網站上。

建立受管理的擴充性架構 (MEF) 專案

若要建立 MEF 專案

建立編輯器類別器的專案。為方案命名 BraceMatchingTest。
VSIX 資訊清單編輯器中開啟 source.extension.vsixmanifest 檔案。
請確定Content名包含 MEF 元件的內容類型，並Path設定為 BraceMatchingTest.dll。
儲存並關閉 Source.extension.vsixmanifest。
刪除現有的類別檔案。

實作符合 Tagger 的大括號

若要取得效果相似 Visual Studio 中所使用的反白顯示在括號，您可以實作型別的 tagger TextMarkerTag。下列程式碼會示範如何定義用於任何層級的巢狀的大括號括號 tagger。在這個範例中，大括號會配對 []。 []，並 {} 定義在 tagger 的建構函式，但在完整的語言實作相關的大括號組應該定義語言規格中。

若要實作的括號對稱 tagger

將類別檔案，並命名為 BraceMatching。

匯入下列命名空間。

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

using System;
using System.Linq;
using System.Collections.Generic;
using System.ComponentModel.Composition;
using Microsoft.VisualStudio.Text;
using Microsoft.VisualStudio.Text.Editor;
using Microsoft.VisualStudio.Text.Tagging;
using Microsoft.VisualStudio.Utilities;

定義類別BraceMatchingTagger繼承自ITagger型別的TextMarkerTag。

Friend Class BraceMatchingTagger
    Implements ITagger(Of TextMarkerTag)

internal class BraceMatchingTagger : ITagger<TextMarkerTag>

加入屬性的文字檢視、來源緩衝區，並在目前的快照集點，以及一組大括號組。

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 _CurrentChar As System.Nullable(Of SnapshotPoint)
Private Property CurrentChar() As System.Nullable(Of SnapshotPoint)
    Get 
        Return _CurrentChar
    End Get 
    Set(ByVal value As System.Nullable(Of SnapshotPoint))
        _CurrentChar = value
    End Set 
End Property 
Private m_braceList As Dictionary(Of Char, Char)

ITextView View { get; set; }
ITextBuffer SourceBuffer { get; set; }
SnapshotPoint? CurrentChar { get; set; }
private Dictionary<char, char> m_braceList;

Tagger 建構函式，在設定屬性及訂閱檢視 change 事件PositionChanged和LayoutChanged。在這個範例中，為說明用途，對稱的括號中也有定義建構函式。

Friend Sub New(ByVal view As ITextView, ByVal sourceBuffer As ITextBuffer)
    'here the keys are the open braces, and the values are the close braces
    m_braceList = New Dictionary(Of Char, Char)()
    m_braceList.Add("{"c, "}"c)
    m_braceList.Add("["c, "]"c)
    m_braceList.Add("("c, ")"c)
    Me.View = view
    Me.SourceBuffer = sourceBuffer
    Me.CurrentChar = Nothing 

    AddHandler Me.View.Caret.PositionChanged, AddressOf Me.CaretPositionChanged
    AddHandler Me.View.LayoutChanged, AddressOf Me.ViewLayoutChanged
End Sub

internal BraceMatchingTagger(ITextView view, ITextBuffer sourceBuffer)
{
    //here the keys are the open braces, and the values are the close braces
    m_braceList = new Dictionary<char, char>();
    m_braceList.Add('{', '}');
    m_braceList.Add('[', ']');
    m_braceList.Add('(', ')');
    this.View = view;
    this.SourceBuffer = sourceBuffer;
    this.CurrentChar = null;

    this.View.Caret.PositionChanged += CaretPositionChanged;
    this.View.LayoutChanged += ViewLayoutChanged;
}

做為一部分的ITagger的實作中，宣告「 TagsChanged 」事件。

Public Event TagsChanged As EventHandler(Of SnapshotSpanEventArgs) _
    Implements ITagger(Of TextMarkerTag).TagsChanged

public event EventHandler<SnapshotSpanEventArgs> TagsChanged;

事件處理常式會更新目前的插入號位置CurrentChar屬性並引發 TagsChanged 事件。

Private Sub ViewLayoutChanged(ByVal sender As Object, ByVal e As TextViewLayoutChangedEventArgs)
    If e.NewSnapshot IsNot e.OldSnapshot Then 
        'make sure that there has really been a change
        UpdateAtCaretPosition(View.Caret.Position)
    End If 
End Sub 

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

Private Sub UpdateAtCaretPosition(ByVal caretPosition As CaretPosition)
    CurrentChar = caretPosition.Point.GetPoint(SourceBuffer, caretPosition.Affinity)

    If Not CurrentChar.HasValue Then 
        Exit Sub 
    End If 

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

void ViewLayoutChanged(object sender, TextViewLayoutChangedEventArgs e)
{
    if (e.NewSnapshot != e.OldSnapshot) //make sure that there has really been a change
    {
        UpdateAtCaretPosition(View.Caret.Position);
    }
}

void CaretPositionChanged(object sender, CaretPositionChangedEventArgs e)
{
    UpdateAtCaretPosition(e.NewPosition);
}
void UpdateAtCaretPosition(CaretPosition caretPosition)
{
    CurrentChar = caretPosition.Point.GetPoint(SourceBuffer, caretPosition.Affinity);

    if (!CurrentChar.HasValue)
        return;

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

實作GetTags方法，使其符合括號是目前的字元時開啟的大括號或前一字元時是關閉的大括號，在 [Visual Studio。當找到符合的項目時，這個方法會產生兩個標記，另一個則用於開啟的大括號和右大括弧。

Public Function GetTags(ByVal spans As NormalizedSnapshotSpanCollection) As IEnumerable(Of ITagSpan(Of TextMarkerTag)) Implements ITagger(Of Microsoft.VisualStudio.Text.Tagging.TextMarkerTag).GetTags
    If spans.Count = 0 Then 
        'there is no content in the buffer 
        Exit Function 
    End If 

    'don't do anything if the current SnapshotPoint is not initialized or at the end of the buffer 
    If Not CurrentChar.HasValue OrElse CurrentChar.Value.Position >= CurrentChar.Value.Snapshot.Length Then 
        Exit Function 
    End If 

    'hold on to a snapshot of the current character 
    Dim currentChar__1 As SnapshotPoint = CurrentChar.Value

    'if the requested snapshot isn't the same as the one the brace is on, translate our spans to the expected snapshot 
    If spans(0).Snapshot IsNot currentChar__1.Snapshot Then
        currentChar__1 = currentChar__1.TranslateTo(spans(0).Snapshot, PointTrackingMode.Positive)
    End If 

    'get the current char and the previous char 
    Dim currentText As Char = currentChar__1.GetChar()
    Dim lastChar As SnapshotPoint = If(CInt(currentChar__1) = 0, currentChar__1, currentChar__1 - 1)
    'if currentChar is 0 (beginning of buffer), don't move it back 
    Dim lastText As Char = lastChar.GetChar()
    Dim pairSpan As New SnapshotSpan()

    If m_braceList.ContainsKey(currentText) Then 
        'the key is the open brace 
        Dim closeChar As Char
        m_braceList.TryGetValue(currentText, closeChar)
        If BraceMatchingTagger.FindMatchingCloseChar(currentChar__1, currentText, closeChar, View.TextViewLines.Count, pairSpan) = True Then 
            Exit Function 
        End If 
    ElseIf m_braceList.ContainsValue(lastText) Then 
        'the value is the close brace, which is the *previous* character  
        Dim open = From n In m_braceList _
            Where n.Value.Equals(lastText) _
            Select n.Key
        If BraceMatchingTagger.FindMatchingOpenChar(lastChar, CChar(open.ElementAt(0)), lastText, View.TextViewLines.Count, pairSpan) = True Then 
            Exit Function 
        End If 
    End If 
End Function

public IEnumerable<ITagSpan<TextMarkerTag>> GetTags(NormalizedSnapshotSpanCollection spans)
{
    if (spans.Count == 0)   //there is no content in the buffer 
        yield break;

    //don't do anything if the current SnapshotPoint is not initialized or at the end of the buffer 
    if (!CurrentChar.HasValue || CurrentChar.Value.Position >= CurrentChar.Value.Snapshot.Length)
        yield break;

    //hold on to a snapshot of the current character
    SnapshotPoint currentChar = CurrentChar.Value;

    //if the requested snapshot isn't the same as the one the brace is on, translate our spans to the expected snapshot 
    if (spans[0].Snapshot != currentChar.Snapshot)
    {
        currentChar = currentChar.TranslateTo(spans[0].Snapshot, PointTrackingMode.Positive);
    }

    //get the current char and the previous char 
    char currentText = currentChar.GetChar();
    SnapshotPoint lastChar = currentChar == 0 ? currentChar : currentChar - 1; //if currentChar is 0 (beginning of buffer), don't move it back 
    char lastText = lastChar.GetChar();
    SnapshotSpan pairSpan = new SnapshotSpan();

    if (m_braceList.ContainsKey(currentText))   //the key is the open brace
    {
        char closeChar;
        m_braceList.TryGetValue(currentText, out closeChar);
        if (BraceMatchingTagger.FindMatchingCloseChar(currentChar, currentText, closeChar, View.TextViewLines.Count, out pairSpan) == true)
        {
            yield return new TagSpan<TextMarkerTag>(new SnapshotSpan(currentChar, 1), new TextMarkerTag("blue"));
            yield return new TagSpan<TextMarkerTag>(pairSpan, new TextMarkerTag("blue"));
        }
    }
    else if (m_braceList.ContainsValue(lastText))    //the value is the close brace, which is the *previous* character 
    {
        var open = from n in m_braceList
                   where n.Value.Equals(lastText)
                   select n.Key;
        if (BraceMatchingTagger.FindMatchingOpenChar(lastChar, (char)open.ElementAt<char>(0), lastText, View.TextViewLines.Count, out pairSpan) == true)
        {
            yield return new TagSpan<TextMarkerTag>(new SnapshotSpan(lastChar, 1), new TextMarkerTag("blue"));
            yield return new TagSpan<TextMarkerTag>(pairSpan, new TextMarkerTag("blue"));
        }
    }
}

下列的私用方法找出在任何層級的巢狀結構對稱的括號。第一種方法可找出符合開啟字元關閉字元：

Private Shared Function FindMatchingCloseChar(ByVal startPoint As SnapshotPoint, ByVal open As Char, ByVal close As Char, ByVal maxLines As Integer, ByRef pairSpan As SnapshotSpan) As Boolean
    pairSpan = New SnapshotSpan(startPoint.Snapshot, 1, 1)
    Dim line As ITextSnapshotLine = startPoint.GetContainingLine()
    Dim lineText As String = line.GetText()
    Dim lineNumber As Integer = line.LineNumber
    Dim offset As Integer = startPoint.Position - line.Start.Position + 1

    Dim stopLineNumber As Integer = startPoint.Snapshot.LineCount - 1
    If maxLines > 0 Then
        stopLineNumber = Math.Min(stopLineNumber, lineNumber + maxLines)
    End If 

    Dim openCount As Integer = 0
    While True 
        'walk the entire line 
        While offset < line.Length
            Dim currentChar As Char = lineText(offset)
            If currentChar = close Then 
                'found the close character 
                If openCount > 0 Then
                    openCount -= 1
                Else 
                    'found the matching close
                    pairSpan = New SnapshotSpan(startPoint.Snapshot, line.Start + offset, 1)
                    Return True 
                End If 
            ElseIf currentChar = open Then 
                ' this is another open
                openCount += 1
            End If
            offset += 1
        End While 

        'move on to the next line 
        If System.Threading.Interlocked.Increment(lineNumber) > stopLineNumber Then 
            Exit While 
        End If

        line = line.Snapshot.GetLineFromLineNumber(lineNumber)
        lineText = line.GetText()
        offset = 0
    End While 

    Return False 
End Function

private static bool FindMatchingCloseChar(SnapshotPoint startPoint, char open, char close, int maxLines, out SnapshotSpan pairSpan)
{
    pairSpan = new SnapshotSpan(startPoint.Snapshot, 1, 1);
    ITextSnapshotLine line = startPoint.GetContainingLine();
    string lineText = line.GetText();
    int lineNumber = line.LineNumber;
    int offset = startPoint.Position - line.Start.Position + 1;

    int stopLineNumber = startPoint.Snapshot.LineCount - 1;
    if (maxLines > 0)
        stopLineNumber = Math.Min(stopLineNumber, lineNumber + maxLines);

    int openCount = 0;
    while (true)
    {
        //walk the entire line 
        while (offset < line.Length)
        {
            char currentChar = lineText[offset];
            if (currentChar == close) //found the close character
            {
                if (openCount > 0)
                {
                    openCount--;
                }
                else     //found the matching close
                {
                    pairSpan = new SnapshotSpan(startPoint.Snapshot, line.Start + offset, 1);
                    return true;
                }
            }
            else if (currentChar == open) // this is another open
            {
                openCount++;
            }
            offset++;
        }

        //move on to the next line 
        if (++lineNumber > stopLineNumber)
            break;

        line = line.Snapshot.GetLineFromLineNumber(lineNumber);
        lineText = line.GetText();
        offset = 0;
    }

    return false;
}

下列的 helper 方法會找出開啟比對關閉字元的字元：

Private Shared Function FindMatchingOpenChar(ByVal startPoint As SnapshotPoint, ByVal open As Char, ByVal close As Char, ByVal maxLines As Integer, ByRef pairSpan As SnapshotSpan) As Boolean
    pairSpan = New SnapshotSpan(startPoint, startPoint)

    Dim line As ITextSnapshotLine = startPoint.GetContainingLine()

    Dim lineNumber As Integer = line.LineNumber
    Dim offset As Integer = startPoint - line.Start - 1
    'move the offset to the character before this one 
    'if the offset is negative, move to the previous line 
    If offset < 0 Then
        line = line.Snapshot.GetLineFromLineNumber(System.Threading.Interlocked.Decrement(lineNumber))
        offset = line.Length - 1
    End If 

    Dim lineText As String = line.GetText()

    Dim stopLineNumber As Integer = 0
    If maxLines > 0 Then
        stopLineNumber = Math.Max(stopLineNumber, lineNumber - maxLines)
    End If 

    Dim closeCount As Integer = 0

    While True 
        ' Walk the entire line 
        While offset >= 0
            Dim currentChar As Char = lineText(offset)

            If currentChar = open Then 
                If closeCount > 0 Then
                    closeCount -= 1
                Else 
                    ' We've found the open character
                    pairSpan = New SnapshotSpan(line.Start + offset, 1)
                    'we just want the character itself 
                    Return True 
                End If 
            ElseIf currentChar = close Then
                closeCount += 1
            End If
            offset -= 1
        End While 

        ' Move to the previous line 
        If System.Threading.Interlocked.Decrement(lineNumber) < stopLineNumber Then 
            Exit While 
        End If

        line = line.Snapshot.GetLineFromLineNumber(lineNumber)
        lineText = line.GetText()
        offset = line.Length - 1
    End While 
    Return False 
End Function

private static bool FindMatchingOpenChar(SnapshotPoint startPoint, char open, char close, int maxLines, out SnapshotSpan pairSpan)
{
    pairSpan = new SnapshotSpan(startPoint, startPoint);

    ITextSnapshotLine line = startPoint.GetContainingLine();

    int lineNumber = line.LineNumber;
    int offset = startPoint - line.Start - 1; //move the offset to the character before this one 

    //if the offset is negative, move to the previous line 
    if (offset < 0)
    {
        line = line.Snapshot.GetLineFromLineNumber(--lineNumber);
        offset = line.Length - 1;
    }

    string lineText = line.GetText();

    int stopLineNumber = 0;
    if (maxLines > 0)
        stopLineNumber = Math.Max(stopLineNumber, lineNumber - maxLines);

    int closeCount = 0;

    while (true)
    {
        // Walk the entire line 
        while (offset >= 0)
        {
            char currentChar = lineText[offset];

            if (currentChar == open)
            {
                if (closeCount > 0)
                {
                    closeCount--;
                }
                else // We've found the open character
                {
                    pairSpan = new SnapshotSpan(line.Start + offset, 1); //we just want the character itself 
                    return true;
                }
            }
            else if (currentChar == close)
            {
                closeCount++;
            }
            offset--;
        }

        // Move to the previous line 
        if (--lineNumber < stopLineNumber)
            break;

        line = line.Snapshot.GetLineFromLineNumber(lineNumber);
        lineText = line.GetText();
        offset = line.Length - 1;
    }
    return false;
}

實作的括號對稱 Tagger 提供者

除了實作 tagger，您也必須實作，並匯出 tagger 提供者。在此情況下，提供者的內容類型是「文字」。這表示括號對稱會出現在所有類型的文字檔案，但簡實作會套用比只對特定的內容類型的大括號。

若要實作的大括號對稱 tagger 提供者

宣告繼承自 tagger 提供者IViewTaggerProvider、其命名為 BraceMatchingTaggerProvider，並將其與匯出ContentTypeAttribute的「文字」，並TagTypeAttribute的TextMarkerTag。

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

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

實作CreateTagger``1 BraceMatchingTagger 具現化的方法。

Public Function CreateTagger(Of T As ITag)(ByVal textView As ITextView, ByVal buffer As ITextBuffer) As ITagger(Of T) Implements IViewTaggerProvider.CreateTagger
    If textView Is Nothing Then 
        Return Nothing 
    End If 

    'provide highlighting only on the top-level buffer 
    If textView.TextBuffer IsNot buffer Then 
        Return Nothing 
    End If 

    Return TryCast(New BraceMatchingTagger(textView, buffer), ITagger(Of T))
End Function

public ITagger<T> CreateTagger<T>(ITextView textView, ITextBuffer buffer) where T : ITag
{
    if (textView == null)
        return null;

    //provide highlighting only on the top-level buffer 
    if (textView.TextBuffer != buffer)
        return null;

    return new BraceMatchingTagger(textView, buffer) as ITagger<T>;
}

建置和測試程式碼

若要測試這段程式碼，建置 BraceMatchingTest 方案並執行它實驗性的執行個體中。

若要建置和測試 BraceMatchingTest 的解決方案

建置方案。
當您執行此專案在偵錯工具時，會執行個體化 Visual Studio 的第二個執行個體。
建立一個文字檔，並輸入一些文字，其中包括對稱的括號。
```
hello {
goodbye}

{}

{hello}
```
當您開啟的大括號之前插入號時，該的大括號和相符的右大括弧都應會反白顯示。當您將游標的位置只會在右大括弧之後時，但是該的大括號，並開啟對稱的大括號應該會醒目提示。

請參閱

工作

逐步解說：連結至檔案的副檔名的內容類型

共用方式為

逐步解說：顯示對稱的括號

必要條件

建立受管理的擴充性架構 (MEF) 專案

若要建立 MEF 專案

實作符合 Tagger 的大括號

若要實作的括號對稱 tagger

實作的括號對稱 Tagger 提供者

若要實作的大括號對稱 tagger 提供者

建置和測試程式碼

若要建置和測試 BraceMatchingTest 的解決方案

請參閱

工作

其他資源

共用方式為

逐步解說： 顯示對稱的括號

必要條件

建立受管理的擴充性架構 (MEF) 專案

若要建立 MEF 專案

實作符合 Tagger 的大括號

若要實作的括號對稱 tagger

實作的括號對稱 Tagger 提供者

若要實作的大括號對稱 tagger 提供者

建置和測試程式碼

若要建置和測試 BraceMatchingTest 的解決方案

請參閱

工作

其他資源

逐步解說：顯示對稱的括號