Help Editor in VB - Printable Version

Code:
Imports System.Drawing

Public Class SnX

    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



    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

            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.Blue.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