I'm coding a simple code editor for a very simple scripting language we use at work. My syntax highlighting code works fine if I do it on the entire RichTextBox
(rtbMain
) but when I try to get it to work on just that line, so I can run the function with rtbMain
changes, it gets weird. I can't seem to figure out why. Am I even going about this the right way?
rtbMain
is the main text box.
frmColors.lbRegExps
is a listbox of words to highlight (later it will have slightly more powerful regular expressions.)
frmColor.lbHexColors
is another listbox with the corresponding hex colors for the words.
Private Sub HighLight(ByVal All As Boolean)
Dim RegExp As System.Text.RegularExpressions.MatchCollection
Dim RegExpMatch As System.Text.RegularExpressions.Match
Dim FirstCharIndex As Integer = rtbMain.GetFirstCharIndexOfCurrentLine
Dim CurrentLine As Integer = rtbMain.GetLineFromCharIndex(FirstCharIndex)
Dim CurrentLineText As String = rtbMain.Lines(CurrentLine)
Dim CharsToCurrentLine As Integer = rtbMain.SelectionStart
Dim PassNumber As Integer = 0
LockWindowUpdate(Me.Handle.ToInt32) 'Let's lock the window so it doesn't scroll all crazy.
If All = True Then 'Highlight everything.
For Each pass In frmColors.lbRegExps.Items
RegExp = System.Text.RegularExpressions.Regex.Matches(LCase(rtbMain.Text), LCase(pass))
For Each RegExpMatch In RegExp
rtbMain.Select(RegExpMatch.Index, RegExpMatch.Length)
rtbMain.SelectionColor = ColorTranslator.FromHtml(frmColors.lbHexColors.Items(PassNumber))
Next
PassNumber += 1
Next
Else 'Highlight just that row.
For Each pass In FrmColors.lbRegExps.Items
RegExp = System.Text.RegularExpressions.Regex.Matches(LCase(CurrentLineText), LCase(pass))
For Each RegExpMatch In RegExp
rtbMain.Select(RegExpMatch.Index + (CharsToCurrentLine - RegExpMatch.Length), RegExpMatch.Length)
rtbMain.SelectionColor = Color.Blue
Next
Next
End If
rtbMain.Select(CharsToCurrentLine, 0) 'Reset colors and positon and then unlock drawing.
rtbMain.SelectionColor = Color.Black
LockWindowUpdate(0)
End Sub