SyntaxHighlighting.vb

Imports System.Collections.Generic
Imports DevExpress.XtraRichEdit.Services
Imports DevExpress.XtraRichEdit.API.Native
Imports DevExpress.CodeParser
Imports System.Drawing
Imports DevExpress.XtraRichEdit

Namespace WindowsFormsApplication1

    Public Class HTMLSyntaxHighlightService
        Implements ISyntaxHighlightService

        Private ReadOnly syntaxEditor As RichEditControl

        Private TokensMapping As Dictionary(Of TokenCategory, SyntaxHighlightProperties) = New Dictionary(Of TokenCategory, SyntaxHighlightProperties)()

        Private textProperties As SyntaxHighlightProperties

        Private Sub AddTokensMapping(ByVal category As TokenCategory, ByVal foreColor As Color)
            Dim tokenProperties As SyntaxHighlightProperties = New SyntaxHighlightProperties()
            tokenProperties.ForeColor = foreColor
            TokensMapping.Add(category, tokenProperties)
        End Sub

        Private Function GetTokensMapping(ByVal category As TokenCategory) As SyntaxHighlightProperties
            If TokensMapping.ContainsKey(category) Then
                Return TokensMapping(category)
            Else
                Return textProperties
            End If
        End Function

        Public Sub New(ByVal syntaxEditor As RichEditControl)
            Me.syntaxEditor = syntaxEditor
        End Sub

        Private Sub HighlightSyntax(ByVal tokens As TokenCollection)
            If TokensMapping.Count = 0 Then
                AddTokensMapping(TokenCategory.HtmlAttributeName, Color.Red)
                AddTokensMapping(TokenCategory.HtmlAttributeValue, Color.Blue)
                AddTokensMapping(TokenCategory.HtmlComment, Color.Green)
                AddTokensMapping(TokenCategory.HtmlElementName, Color.Brown)
                AddTokensMapping(TokenCategory.HtmlEntity, Color.Green)
                AddTokensMapping(TokenCategory.HtmlOperator, Color.Blue)
                AddTokensMapping(TokenCategory.HtmlServerSideScript, Color.Gray)
                AddTokensMapping(TokenCategory.HtmlString, Color.Black)
                AddTokensMapping(TokenCategory.HtmlTagDelimiter, Color.Blue)
                AddTokensMapping(TokenCategory.CssComment, Color.Green)
                AddTokensMapping(TokenCategory.CssKeyword, Color.Red)
                AddTokensMapping(TokenCategory.CssPropertyName, Color.Red)
                AddTokensMapping(TokenCategory.CssPropertyValue, Color.Blue)
                AddTokensMapping(TokenCategory.CssSelector, Color.Brown)
                AddTokensMapping(TokenCategory.CssStringValue, Color.Blue)
                textProperties = New SyntaxHighlightProperties()
                textProperties.ForeColor = Color.Black
            End If

            If tokens Is Nothing OrElse tokens.Count = 0 Then Return
            Dim document As Document = syntaxEditor.Document
            Dim syntaxTokens As List(Of SyntaxHighlightToken) = New List(Of SyntaxHighlightToken)(tokens.Count)
            For Each token As Token In tokens
                HighlightCategorizedToken(CType(token, CategorizedToken), syntaxTokens)
            Next

            document.ApplySyntaxHighlight(syntaxTokens)
        End Sub

        Private Sub HighlightCategorizedToken(ByVal token As CategorizedToken, ByVal syntaxTokens As List(Of SyntaxHighlightToken))
            Dim backColor As Color = syntaxEditor.ActiveView.BackColor
            Dim category As TokenCategory = token.Category
            syntaxTokens.Add(SetTokenColor(token, GetTokensMapping(category), backColor))
        End Sub

        Private Function SetTokenColor(ByVal token As Token, ByVal foreColor As SyntaxHighlightProperties, ByVal backColor As Color) As SyntaxHighlightToken
            If syntaxEditor.Document.Paragraphs.Count < token.Range.Start.Line Then Return Nothing
            Dim paragraphStart As Integer = DocumentHelper.GetParagraphStart(syntaxEditor.Document.Paragraphs(token.Range.Start.Line - 1))
            Dim tokenStart As Integer = paragraphStart + token.Range.Start.Offset - 1
            If token.Range.End.Line <> token.Range.Start.Line Then paragraphStart = DocumentHelper.GetParagraphStart(syntaxEditor.Document.Paragraphs(token.Range.End.Line - 1))
            Dim tokenEnd As Integer = paragraphStart + token.Range.End.Offset - 1
            Return New SyntaxHighlightToken(tokenStart, tokenEnd - tokenStart, foreColor)
        End Function

'#Region "#ISyntaxHighlightServiceMembers"
        Public Sub Execute() Implements ISyntaxHighlightService.Execute
            Dim newText As String = syntaxEditor.Text
            ' Use DevExpress.CodeParser to parse text into tokens.
            Dim tokenHelper As ITokenCategoryHelper = TokenCategoryHelperFactory.CreateHelper(ParserLanguageID.Html)
            Dim highlightTokens As TokenCollection
            highlightTokens = tokenHelper.GetTokens(newText)
            HighlightSyntax(highlightTokens)
        End Sub

        Public Sub ForceExecute() Implements ISyntaxHighlightService.ForceExecute
            Execute()
        End Sub
'#End Region  ' #ISyntaxHighlightServiceMembers
    End Class
End Namespace