[GUIDE] Syntax Highlighting in RichTextBox

[VBTutorials]

RichTextBox Syntax Highlighting

Welcome to my guide on how to highlight syntax keywords such as: 'public, new, else, if, etc...'
First we will go through how to do it with VB.NET, I am currently using Visual Basic 2010 Express.


VB.NET Guide:

1. Open up VB and create a new project.


2. Customize the form to whatever you desire.

3. Add a RichTextBox and set the properties so it looks professional.


4.Now double click on the RichTextBox to get to the code event of RichTextBox.TextChanged

5. Now replace your current code with this:

Imports System.Text.RegularExpressions

Public Class Form1

    Private Sub RichTextBox1_TextChanged(sender As System.Object, e As System.EventArgs) Handles RichTextBox1.TextChanged

Dim tokens As String = "(regex|dim|object|new|string|public|integer|end|auto|double|int|struct|break|else|long|switch|case|enum|register|typedef|char|extern|return|union|const|float|short|unsigned|continue|for|signed|void|default|goto|sizeof|volatile|do|if|static|while|1|2|3|4|5|6|7|8|9|my)"
        Dim rex As New Regex(tokens)
        Dim mc As MatchCollection = rex.Matches(RichTextBox1.Text)
        Dim StartCursorPosition As Integer = RichTextBox1.SelectionStart
        For Each m As Match In mc
            Dim startIndex As Integer = m.Index
            Dim StopIndex As Integer = m.Length
            RichTextBox1.[Select](startIndex, StopIndex)
            RichTextBox1.SelectionColor = Color.Blue
            RichTextBox1.SelectionStart = StartCursorPosition

            RichTextBox1.SelectionColor = Color.Black
        Next
    End Sub
End Class

-- Now lets go over the pieces of code individually.

Dim tokens As String = "(regex|dim|object|new|string|public|integer|end|auto|double|int|struct|break|else|long|switch|case|enum|register|typedef|char|extern|return|union|const|float|short|unsigned|continue|for|signed|void|default|goto|sizeof|volatile|do|if|static|while|1|2|3|4|5|6|7|8|9|my)"

^^^ This creates a new string with all of the keywords that will be highlighted.

        Dim rex As New Regex(tokens)
        Dim mc As MatchCollection = rex.Matches(RichTextBox1.Text)
        Dim StartCursorPosition As Integer = RichTextBox1.SelectionStart

^^^ This creates some variables that will be able to search for text in the RichTextBox later.

For Each m As Match In mc
            Dim startIndex As Integer = m.Index
            Dim StopIndex As Integer = m.Length
            RichTextBox1.[Select](startIndex, StopIndex)
            RichTextBox1.SelectionColor = Color.Blue
            RichTextBox1.SelectionStart = StartCursorPosition

            RichTextBox1.SelectionColor = Color.Black
        Next

^^^ This section sets up a 'For Statement' that will keep searching for the keywords defined in the string: 'tokens', and will hightlight them BLUE with the code:

RichTextBox1.SelectionColor = Color.Blue

and then set it back to BLACK with:

RichTextBox1.SelectionColor = Color.Black

[b]Thanks for reading! I hope I could help. If you need ANY help, don't hesitate to ask!

The C# Portion will be made later.


Created by MASON COOPER
Please give credit to me (by linking) if you decide to redistribute this guide!