通过

演练:显示匹配的大括号

可以实现与语言为基础的功能 (如匹配通过定义要匹配的大括号，然后添加的大括号文本标记一直到含有匹配的大括号，在插入符号位于某个大括号时。 可以定义大括号在语言中，也可以定义拥有文件扩展名与内容类型和标记应用于该类型，也可以将标记应用于现有内容类型 (例如 “text”)。 下面的演练演示如何应用括号匹配的标记应用到 “text”内容类型。

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。

创建一个 managed extensibility framework 项目 (MEF)

创建 MEF 项目

  1. 创建一个编辑分类器项目。 将解决方案命名为 BraceMatchingTest。

  2. 打开在 VSIX 清单编辑器中的 source.extension.vsixmanifest 文件。

  3. 确保 Content 归为包含一个 MEF 组件内容类型，而 Path 设置为 BraceMatchingTest.dll。

  4. 保存并关闭的 Source.extension.vsixmanifest。

  5. 删除现有类文件。

实现大括号匹配的标记

获取显示类似于个在 Visual Studio 的影响的大括号，可以实现类型 TextMarkerTag标记。 下面的代码演示如何定义大括号的标记对嵌套级别。 在此示例中，该大括号对 []。 []，并且， {} 在标记构造函数定义，但是，在该相关大括号对的进行完整语言实施者应定义在语言规范 (cls)。

实现大括号匹配的标记

  1. 将类文件并将其命名为 BraceMatching。

  2. 导入下列命名空间。

    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;

  3. 定义从类型继承 TextMarkerTagITagger 的类 BraceMatchingTagger 。

    Friend Class BraceMatchingTagger
    Implements ITagger(Of TextMarkerTag)

    internal class BraceMatchingTagger : ITagger<TextMarkerTag>

  4. 添加文本视图中，源缓冲区属性，并且，当前快照点，并设置大括号对。

    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;

  5. 在标记构造函数中，设置属性并订阅视图更改事件 PositionChanged 和 LayoutChanged。 在此示例中，用于说明目的，构造函数相对还定义。

    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;
}

  6. 作为 ITagger 实现一部分，声明 TagsChanged 事件。

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

    public event EventHandler<SnapshotSpanEventArgs> TagsChanged;

  7. 事件处理程序更新 CurrentChar 属性的当前脱字号位置并引发 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)));
}

  8. 请执行 GetTags 方法与大括号其中之一，在当前字符是一个左大括号时，或者当字符是一个关闭的大括号时， Visual Studio。 当找到匹配项时，此方法实例化两个标记，其中打开大括号的另一个用于关闭的大括号的。

    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"));
        }
    }
}

  9. 以下私有方法查找匹配的大括号在嵌套级别。 第一个方法查找与打开字符的结束字符:

    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;
}

  10. 下面的帮助器方法查找与结束字符的打开字符:

    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;
}

实现大括号匹配的标记提供程序

除实现标记外，您还必须实现和导出标记提供程序。 在这种情况下，提供的内容类型为 “text”。 这意味着括号匹配将出现在文本文件中的所有类型，但是，一次更全面的实现将应用只匹配到特定内容类型的大括号。

实现大括号匹配的标记提供程序

  1. 声明从 IViewTaggerProvider继承的标记提供程序，将其命名为 BraceMatchingTaggerProvider，并将其导出与 “text” ContentTypeAttribute 和 TextMarkerTagTagTypeAttribute 。

    <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

  2. 执行 CreateTagger``1 方法实例化 BraceMatchingTagger。

    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>;
}

生成并测试代码

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

生成和测试 BraceMatchingTest 解决方案

  1. 生成解决方案。

  2. 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。

  3. 创建一个文本文件并键入包含匹配的大括号的某些文本。

    hello {
goodbye}

{}

{hello}

  4. 当您确定插入符号，在左大括号，辅助，和的两个预先时应显示匹配的结束大括号。 当确定光标，在 " 关闭 " 大括号，辅助，和的两个后期时应显示匹配的左大括号。

请参见

任务

演练:链接到文件扩展名的内容类型