[2005] Syntax Highliting in TextBox

I want to create a text editor where the user will be able to download files/add-ons that will highlight the code in their file.

I want it to be a file/add-on so that it is not hard coded into the thing and i can charge for them and so on...

How would be the best way to go about this? Would i need to use a richtextbox?

Yes, you would need to use a richtextbox.

One way to do it is using a keyword file for each language you want highlighted.

ok i have the rest of the project done, except for the syntax highlighting. Does any one know what i should do?

An example is at;

http://pietschsoft.com/Blog/Post.aspx?PostID=491

i got the code from the post above this one. Can some one tell me how it knows what code to highlight?

vb Code:

Public Class SyntaxRTB
 
   Inherits System.Windows.Forms.RichTextBox
 
   Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
      (ByVal hWnd As IntPtr, ByVal wMsg As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer
 
 
   Private Declare Function LockWindowUpdate Lib "user32" (ByVal hWnd As Integer) As Integer
 
   Private _SyntaxHighlight_CaseSensitive As Boolean = False
 
   Private Words As New DataTable
 
   'Contains Windows Messages for the SendMessage API call
   Private Enum EditMessages
      LineIndex = 187
      LineFromChar = 201
      GetFirstVisibleLine = 206
      CharFromPos = 215
      PosFromChar = 1062
   End Enum
 
   Protected Overrides Sub OnTextChanged(ByVal e As System.EventArgs)
      ColorVisibleLines()
   End Sub
 
   Public Sub ColorRtb()
      Dim FirstVisibleChar As Integer
      Dim i As Integer = 0
 
      While i < Me.Lines.Length
         FirstVisibleChar = GetCharFromLineIndex(i)
         ColorLineNumber(i, FirstVisibleChar)
         i += 1
      End While
   End Sub
 
   Public Sub ColorVisibleLines()
      Dim FirstLine As Integer = FirstVisibleLine()
      Dim LastLine As Integer = LastVisibleLine()
      Dim FirstVisibleChar As Integer
 
      If (FirstLine = 0) And (LastLine = 0) Then
         'If there is no text it will error, so exit the sub
         Exit Sub
      Else
         While FirstLine < LastLine
            FirstVisibleChar = GetCharFromLineIndex(FirstLine)
            ColorLineNumber(FirstLine, FirstVisibleChar)
            FirstLine += 1
         End While
      End If
 
   End Sub
 
   Public Sub ColorLineNumber(ByVal LineIndex As Integer, ByVal lStart As Integer)
      Dim i As Integer = 0
      Dim Instance As Integer
      Dim LeadingChar, TrailingChar As String
      Dim SelectionAt As Integer = Me.SelectionStart
      Dim MyRow As DataRow
      Dim Line() As String, MyI As Integer, MyStr As String
 
      ' Lock the update
      LockWindowUpdate(Me.Handle.ToInt32)
 
      MyI = lStart
 
      If CaseSensitive Then
         Line = Split(Me.Lines(LineIndex).ToString, " ")
      Else
         Line = Split(Me.Lines(LineIndex).ToLower, " ")
      End If
 
      For Each MyStr In Line
         Me.SelectionStart = MyI
         Me.SelectionLength = MyStr.Length
 
         If Words.Rows.Contains(MyStr) Then
            MyRow = Words.Rows.Find(MyStr)
            If (Not CaseSensitive) Or (CaseSensitive And MyRow("Word") = MyStr) Then
               Me.SelectionColor = Color.FromName(MyRow("Color"))
            End If
         Else
            Me.SelectionColor = Color.Black
         End If
 
         MyI += MyStr.Length + 1
      Next
 
      ' Restore the selectionstart
      Me.SelectionStart = SelectionAt
      Me.SelectionLength = 0
      Me.SelectionColor = Color.Black
 
      ' Unlock the update
      LockWindowUpdate(0)
   End Sub
 
   Public Function GetCharFromLineIndex(ByVal LineIndex As Integer) As Integer
      Return SendMessage(Me.Handle, EditMessages.LineIndex, LineIndex, 0)
   End Function
 
   Public Function FirstVisibleLine() As Integer
      Return SendMessage(Me.Handle, EditMessages.GetFirstVisibleLine, 0, 0)
   End Function
 
   Public Function LastVisibleLine() As Integer
      Dim LastLine As Integer = FirstVisibleLine() + (Me.Height / Me.Font.Height)
 
      If LastLine > Me.Lines.Length Or LastLine = 0 Then
         LastLine = Me.Lines.Length
      End If
 
      Return LastLine
   End Function
 
   Public Sub New()
      Dim MyRow As DataRow
      Dim arrKeyWords() As String, strKW As String
 
      Me.AcceptsTab = True
 
      ''Load all the keywords and the colors to make them 
      Words.Columns.Add("Word")
      Words.PrimaryKey = New DataColumn() {Words.Columns(0)}
      Words.Columns.Add("Color")
 
      arrKeyWords = New String() {"select", "insert", "delete", _
         "truncate", "from", "where", "into", "inner", "update", _
         "outer", "on", "is", "declare", "set", "use", "values", "as", _
         "order", "by", "drop", "view", "go", "trigger", "cube", _
         "binary", "varbinary", "image", "char", "varchar", "text", _
         "datetime", "smalldatetime", "decimal", "numeric", "float", _
         "real", "bigint", "int", "smallint", "tinyint", "money", _
         "smallmoney", "bit", "cursor", "timestamp", "uniqueidentifier", _
         "sql_variant", "table", "nchar", "nvarchar", "ntext", "left", _
         "right", "like","and","all","in","null","join","not","or"}
 
      For Each strKW In arrKeyWords
         MyRow = Words.NewRow()
         MyRow("Word") = strKW
         MyRow("Color") = Color.LightCoral.Name
         Words.Rows.Add(MyRow)
      Next
 
   End Sub
 
 
   Public Property CaseSensitive() As Boolean
      Get
         Return _SyntaxHighlight_CaseSensitive
      End Get
      Set(ByVal Value As Boolean)
         _SyntaxHighlight_CaseSensitive = Value
      End Set
   End Property

See the array called "arrKeyWords"

Code:

---

      arrKeyWords = New String() {"select", "insert", "delete",
_        "truncate", "from", "where", "into", "inner", "update",
_        "outer", "on", "is", "declare", "set", "use", "values", "as",
_        "order", "by", "drop", "view", "go", "trigger", "cube",
_        "binary", "varbinary", "image", "char", "varchar", "text",
_        "datetime", "smalldatetime", "decimal", "numeric", "float",
_        "real", "bigint", "int", "smallint", "tinyint", "money",
_        "smallmoney", "bit", "cursor", "timestamp", "uniqueidentifier",
_        "sql_variant", "table", "nchar", "nvarchar", "ntext", "left",
_        "right", "like","and","all","in","null","join","not","or"}

---

So i put the codes (words) to be highlighed in that array and they will all be the same color? I kinda wannted more then that... like say

<a href="someURL">Blah</a>

You could create multiple arrays for different keywords which can be displayed in different colors. In order to do this you'll need to write some code, everything you need is present in that example, just extend it.

The color used for each string is set here;

Code:

---

      For Each strKW In arrKeyWords
        MyRow = Words.NewRow()
        MyRow("Word") = strKW
        MyRow("Color") = Color.LightCoral.Name
        Words.Rows.Add(MyRow)
      Next

---

If you want more elaborate highlighting, like tags in HTML, then you will need to use regular expressions.