Spell Check with RichTextBox Control

Posted Date: 30 Sep 2005	Resource Type: Articles	Category: .NET Framework
Author: Sanjeevi Kumar S	Member Level: Bronze
Rating:	Points: 12

Introduction

This article discusses about a program that adds spell check functionality to a RichTextBox control.

Consider you have a project in which there is a form with RichTextBox control or simply create a project with a form having RichTextBox control.

Create a Class to hold the dictionary in a DataSet object and to maintain the ChangeAll word list in the HashTable object. An object of this class should be created to invoke a spell check form which is the second additional thing to be added to your application. The spell checker form has all the options of a normal spell check process - such as Ignore, IgnoreAll, Change, ChangeAll, Add to Dictionary.

I have used a access database to maintain the dictionary. There are two tables and one among them is used to store the user selected words by the option “Add to Dictionary” while execution of spell checker form.

Add to Project

Create a project and a form with RichTextBox control if you haven't done so.

1) Add a Class. The class will contain the following code


Imports System.Data.OleDb

Public Class RTBSpellChecker
    Public ConnStr As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & Application.StartupPath & "\Dict.mdb"
    Public Conn As OleDbConnection
    Public Cmd As OleDbCommand
    Public Cmd2 As OleDbCommand
    Public Adp As OleDbDataAdapter
    Public Adp2 As OleDbDataAdapter
    Public CmB2 As OleDbCommandBuilder
    Public DicT As DataSet
    Public IgnoreAllList As New Hashtable
    Public ChangeAllList As New Hashtable

    Sub New()
        Conn = New OleDbConnection(ConnStr)
        Conn.Open()
        Cmd = New OleDbCommand("Select * from Words", Conn)
        Cmd2 = New OleDbCommand("Select * from Custom", Conn)
        Adp = New OleDbDataAdapter(Cmd)
        Adp2 = New OleDbDataAdapter(Cmd2)
        CmB2 = New OleDbCommandBuilder(Adp2)
        DicT = New DataSet("Dict")
        Adp.Fill(DicT, "Words")
        Adp2.Fill(DicT, "Custom")
        Dim DC(0) As DataColumn
        DC(0) = DicT.Tables("Words").Columns(0)
        DicT.Tables("Words").PrimaryKey = DC
        Dim Dr As DataRow
        For Each Dr In DicT.Tables("Custom").Rows
            Dim Dr2 As DataRow
            Dr2 = DicT.Tables("Words").NewRow
            Dr2.Item(0) = Dr.Item(0)
            Try
                DicT.Tables("Words").Rows.Add(Dr2)
            Catch ex As Exception
            End Try
            Dr2 = Nothing
        Next
    End Sub
End Class

2) Add a Windows form with the following properties

Name : frMSpellCheck
FormBorderStyle : FixedToolWindow
Size : as per your requirement
Text : Spell Checker (whatever you want)

Add two TextBoxes to this form with names 'Word1' and 'Word2' (one for showing notfound word in dictionary and another for change with text).

Put 6 command buttons and the name of the buttons should be btnIgore, btnIgnoreAll, btnChange, btnChangeAll, btnAdd2Dict, btnCancel

The code below is a set of functions to be added



#Region "Variables"
    Private Rtbox As RichTextBox
    Private SChk As RTBSpellChecker
    Private CurWord As String, CurLoc As String
    Private StartLoc As Integer, EndLoc As Integer, TotalLoc As Integer, cl As Integer
    Private Ended As Boolean = False
    Private ScheckDiff As Integer
    Private msgvar As Integer
#End Region

#Region "Private Functions"
    Private Function Initiate()
        cl = Rtbox.SelectionStart
        If Rtbox.SelectionLength = 0 Then
            StartLoc = 1
            EndLoc = Rtbox.TextLength
            TotalLoc = Rtbox.SelectionLength
        Else
            StartLoc = Rtbox.SelectionStart + 1
            EndLoc = Rtbox.SelectionStart + Rtbox.SelectionLength
            TotalLoc = Rtbox.SelectionLength
        End If
        CurLoc = StartLoc
    End Function

    Private Function FindNextNotFound()
        Word2.Text = ""
        If Ended Then
            Rtbox.SelectionLength = 0
            Rtbox.SelectionStart = cl
            msgvar += 1
            If msgvar = 1 Then MsgBox("Spell Check has been Completed")
            Me.Dispose()
            Exit Function
        End If
        Word1.Text = ""
        While True
            If Word1.Text <> "" Then Exit While
            CurWord = FindCurWord()
            If Ended = True Then Exit While
            ChkWord(CurWord)
        End While
        If Ended And Word1.Text = "" Then
            Rtbox.SelectionLength = 0
            Rtbox.SelectionStart = cl
            msgvar += 1
            If msgvar = 1 Then MsgBox("Spell Check has been Completed")
            Me.Dispose()
            Exit Function
        End If
    End Function

    Private Function ChkWord(ByVal Word As String)
        Dim S As String = ""
        Try
            S = SChk.ChangeAllList.Item(Word)
        Catch ex1 As System.NullReferenceException
        Catch ex2 As Exception
        End Try
        If S <> "" Then
            Word2.Text = S
            NotFound(Word)
            ChangeWord()
            FindNextNotFound()
            Exit Function
        End If
        If SChk.DicT.Tables("Words").Rows.Contains(Word) Then
            Word1.Text = ""
        Else
            If Len(Word) >= 3 And Word.Substring(Len(Word) - 1, 1).ToLower = "s" Then
                If SChk.DicT.Tables("Words").Rows.Contains(Word.Substring(0, Len(Word) - 1)) Then
                    Word1.Text = ""
                Else
                    NotFound(Word)
                End If
            Else
                NotFound(Word)
            End If
        End If
    End Function

    Private Function NotFound(ByVal Word)
        Word1.Text = Word
        Rtbox.SelectionStart = CurLoc - Len(Word) - 2
        Rtbox.SelectionLength = Len(Word)
        CurLoc = CurLoc + ScheckDiff
    End Function

    Private Function ChangeWord()
        Rtbox.SelectedText = Word2.Text
        ScheckDiff = Len(Word2.Text) - Len(Word1.Text)
        CurLoc += ScheckDiff
        EndLoc += ScheckDiff
        ScheckDiff = 0
    End Function

    Private Function FindCurWord() As String
        If Ended Then Exit Function
        Dim C As Char, Word As String = ""
        While True
            C = Mid(Rtbox.Text, CurLoc, 1)
            If Char.IsLetter(Chr(Asc(C))) Then
                CurLoc += 1
                If CurLoc >= EndLoc Then Ended = True : Exit While
                Word += C
            Else
                CurLoc += 1
                If CurLoc >= EndLoc Then Ended = True : Exit While
                If Len(Word) > 0 Then Exit While
            End If
        End While
        Return Word
    End Function

    Private Function AddToDictionary()
        Dim DR1 As DataRow, DR2 As DataRow
        DR1 = SChk.DicT.Tables("Words").NewRow
        DR2 = SChk.DicT.Tables("Custom").NewRow
        DR1.Item(0) = Word1.Text
        DR2.Item(0) = Word1.Text
        SChk.DicT.Tables("Words").Rows.Add(DR1)
        SChk.DicT.Tables("Custom").Rows.Add(DR2)
        SChk.Adp2.Update(SChk.DicT, "Custom")
    End Function

    Private Function AddToIgnoreAllList()
        Dim dr As DataRow = SChk.DicT.Tables("Words").NewRow
        dr.Item(0) = Word1.Text
        SChk.DicT.Tables("Words").Rows.Add(dr)
    End Function

    Private Function AddToIgnoreAllList(ByVal Word)
        Dim dr As DataRow = SChk.DicT.Tables("Words").NewRow
        dr.Item(0) = Word
        SChk.DicT.Tables("Words").Rows.Add(dr)
    End Function

    Private Function AddToChangeAllList()
        Try
            SChk.ChangeAllList.Add(Word1.Text, Word2.Text)
        Catch ex As ArgumentException
        End Try
    End Function
#End Region

#Region "Public Functions"
    Public Function setSP(ByRef RichTxtBox As RichTextBox, ByRef Sc As RTBSpellChecker)
        Rtbox = RichTxtBox
        SChk = Sc
        Rtbox.HideSelection = False
    End Function
#End Region

Also add event handlers to all 6 buttons


   Private Sub frMSpellCheck_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Initiate()
        FindNextNotFound()
    End Sub

    Private Sub btnIgnore_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnIgnore.Click
        FindNextNotFound()
    End Sub

    Private Sub btnIgnoreAll_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnIgnoreAll.Click
        AddToIgnoreAllList()
        FindNextNotFound()
    End Sub

    Private Sub btnChange_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnChange.Click
        ChangeWord()
        FindNextNotFound()
    End Sub

    Private Sub butChangeAll_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles butChangeAll.Click
        AddToChangeAllList()
        ChangeWord()
        FindNextNotFound()
    End Sub

    Private Sub butCancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles butCancel.Click
        Me.Dispose()
    End Sub

    Private Sub btnAdd2Dict_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd2Dict.Click
        AddToDictionary()
        FindNextNotFound()
    End Sub

The dictioinary

This spell checker uses a access database (mdb file) as its english dictionary. So you have to create a access database with the name "Dict.mdb" and should be stored in you project's bin directory i.e application path or exe file directory.

Create a table with name "Words" in which create a column with name "Word" and with type "Text".

Also create a table with name "Custom" in which create a column with name "Word" and with type "Text".

Add all the english words to the Words table. You don't need to add plural forms.

The custom dictionary will be updated at runtime with the option "Add to Dictionary".

If anyone wants the dictionary with morethan 100000 words, request mail to me for Access database.

Final Step

Go to the having RichTextBox. Add a button to invoke the Spell Checker with name "btnSpell" with the following code.

Public SChecker As RTBSpellChecker

Add the following in form load event

SChecker = New RTBSpellChecker

Add the following in click event of btnSpell button


        Dim objfrmSpellCheck As New frMSpellCheck
        objfrmSpellCheck.setSP(RichTextBox1, SChecker)
        objfrmSpellCheck.ShowDialog(me)

Responses

Author: Praveen Pula 13 Aug 2009 Member Level: Gold Points : 1

Hi it is a good article

if you have sample working code please update it hear.

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