这是一个简单的类，它为RichTextBox和TextBox控件启用文本的多个Selections和Highlight。
您可以将这个类别的多个执行严修用于不同的控件。
您可以将“要选择/突出显示的单词”添加到列表中，并指定用于选择和/或突出显示文本的颜色。

Dim listOfWords As WordList = New WordList(RichTextBox1)

listOfWords.AddRange({"Word1", "Word2"})
listOfWords.SelectionColor = Color.LightBlue
listOfWords.HighLightColor = Color.Yellow

以下是类操作的可视结果：

在此示例中，单词列表使用以下内容填充：

Dim patterns As String() = TextBox1.Text.Split()
listOfWords.AddRange(patterns)

在视觉化范例中，Class是以下列方式设定：

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Dim patterns As String() = TextBox1.Text.Split()

    Dim listOfWords As WordList = New WordList(RichTextBox1)
    listOfWords.AddRange(patterns)
    listOfWords.SelectionColor = Color.LightBlue
    listOfWords.HighLightColor = Color.Yellow

    If RadioButton1.Checked = True Then
        listOfWords.WordsSelect()
    ElseIf RadioButton2.Checked Then
        listOfWords.WordsHighLight()
    Else
        listOfWords.DeselectAll()
    End If
End Sub

这是用于生成Selections和HighLights的类：

Imports System.Drawing.Text
Imports System.Text.RegularExpressions

Public Class WordList
    Private TextRendererFlags As TextFormatFlags =
        TextFormatFlags.Top Or TextFormatFlags.Left Or TextFormatFlags.NoPadding Or
        TextFormatFlags.WordBreak Or TextFormatFlags.TextBoxControl

    Private textControl As RichTextBox = Nothing
    Private wordsList As List(Of Word)

    Public Sub New(rtb As RichTextBox)
        textControl = rtb
        wordsList = New List(Of Word)
        ProtectSelection = False
    End Sub

    Public Property ProtectSelection As Boolean
    Public Property HighLightColor As Color
    Public Property SelectionColor As Color

    Public Sub Add(word As String)
        wordsList.Add(New Word() With {.Word = word, .Indexes = GetWordIndexes(word)})
    End Sub

    Public Sub AddRange(words As String())
        For Each WordItem As String In words
            wordsList.Add(New Word() With {.Word = WordItem, .Indexes = GetWordIndexes(WordItem)})
        Next
    End Sub
    Private Function GetWordIndexes(word As String) As List(Of Integer)
        Return Regex.Matches(textControl.Text, word).
                     OfType(Of Match)().
                     Select(Function(chr) chr.Index).ToList()
    End Function

    Public Sub DeselectAll()
        If textControl IsNot Nothing Then
            textControl.SelectAll()
            textControl.SelectionBackColor = textControl.BackColor
            textControl.Update()
        End If
    End Sub

    Public Sub WordsHighLight()
        If wordsList.Count > 0 Then
            For Each WordItem As Word In wordsList
                For Each Position As Integer In WordItem.Indexes
                    Dim p As Point = textControl.GetPositionFromCharIndex(Position)
                    TextRenderer.DrawText(textControl.CreateGraphics(), WordItem.Word,
                                          textControl.Font, p, textControl.ForeColor,
                                          HighLightColor, TextRendererFlags)
                Next
            Next
        End If
    End Sub

    Public Sub WordsSelect()
        DeselectAll()
        If wordsList.Count > 0 Then
            For Each WordItem As Word In wordsList
                For Each Position As Integer In WordItem.Indexes
                    textControl.Select(Position, WordItem.Word.Length)
                    textControl.SelectionColor = textControl.ForeColor
                    textControl.SelectionBackColor = SelectionColor
                    textControl.SelectionProtected = ProtectSelection
                Next
            Next
        End If
    End Sub

    Friend Class Word
        Property Word As String
        Property Indexes As List(Of Integer)
    End Class
End Class

使用模块，您可以这样做：

Imports System.Runtime.CompilerServices

Module Utility

<Extension()>
Sub HighlightText(ByVal myRtb As RichTextBox, ByVal word As String, ByVal color As Color)
    If word = String.Empty Then Return
    Dim index As Integer, s_start As Integer = myRtb.SelectionStart, startIndex As Integer = 0
    While(__InlineAssignHelper(index, myRtb.Text.IndexOf(word, startIndex))) <> -1
        myRtb.[Select](index, word.Length)
        myRtb.SelectionColor = color
        startIndex = index + word.Length
    End While

    myRtb.SelectionStart = s_start
    myRtb.SelectionLength = 0
    myRtb.SelectionColor = Color.Black
End Sub

<Obsolete("Please refactor code that uses this function, it is a simple work-around to simulate inline assignment in VB!")>
Private Shared Function __InlineAssignHelper(Of T)(ByRef target As T, value As T) As T
    target = value
    Return value
End Function
End Module

或者，你也可以使用这个，因为它可以让你同时突出显示多个单词：

Private Sub HighlightWords(ByVal words() As String)
     Private Sub HighlightWords(ByVal words() As String)
    For Each word As String In words
        Dim startIndex As Integer = 0

        While (startIndex < rtb1.TextLength)
            Dim wordStartIndex As Integer = rtb1.Find(word, startIndex, RichTextBoxFinds.None)
            If (wordStartIndex <> -1) Then
                rtb1.SelectionStart = wordStartIndex
                rtb1.SelectionLength = word.Length
                rtb1.SelectionBackColor = System.Drawing.Color.Black
            Else
                Exit While
            End If

            startIndex += wordStartIndex + word.Length
        End While

    Next
End Sub

Source希望这对你有帮助：）

这是可行的

Public Sub HighlightText(ByVal txt As String, ByVal obj As RichTextBox)

    obj.SelectionStart = 0
    obj.SelectAll()
    obj.SelectionBackColor = Color.White

    Dim len = txt.Length
    Dim pos = obj.Find(txt, 0, RichTextBoxFinds.NoHighlight)
    While (pos >= 0)
        obj.Select(pos, len)
        obj.SelectionBackColor = Color.Yellow
        If pos + len >= obj.Text.Length Then
            Exit While
        End If
        pos = obj.Find(txt, pos + len, RichTextBoxFinds.NoHighlight)
    End While
End Sub

Public Sub HighlightText(ByVal txt As String, ByVal obj As RichTextBox)

    obj.SelectionStart = 0
    obj.SelectAll()
    obj.SelectionBackColor = Color.White

    Dim len = txt.Length
    Dim pos = obj.Find(txt, 0, RichTextBoxFinds.NoHighlight)
    While (pos >= 0)
        obj.Select(pos, len)
        obj.SelectionBackColor = Color.Yellow
        If pos + len >= obj.Text.Length Then
            Exit While
        End If
        pos = obj.Find(txt, pos + len, RichTextBoxFinds.NoHighlight)
    End While
End Sub