Comparar Textos de Duas RichTextBox e Destacar o Erro

[nando.m]

olá sou novo aqui no forum, me desculpem se postei em lugar errado ou algo do tipo...

estou com um problema em um programa que estou fazendo, preciso comparar o texto de duas textboxs e destacar o caractere difirente (errado).

por exemplo assim que a pessoa digitar um caractere ele confere no textbox (estou usando timer) se o caractere digitado no rich..box2 for difirente do rich..box1 ele destaca com uma cor algo assim...

Aqui em baixo está o codigo do meu programa. por favor me ajudem!

Public Class Form2
    Dim Voice As Object

    Private Sub LinkLabel2_LinkClicked(ByVal sender As System.Object, ByVal e As System.Windows.Forms.LinkLabelLinkClickedEventArgs) Handles LinkLabel2.LinkClicked
        Form3.Show()
        Me.Close()
    End Sub

    Private Sub LinkLabel1_LinkClicked(ByVal sender As System.Object, ByVal e As System.Windows.Forms.LinkLabelLinkClickedEventArgs) Handles LinkLabel1.LinkClicked
        Form4.Show()
        Me.Close()
    End Sub

    Private Sub LinkLabel1_MouseMove(ByVal sender As Object, ByVal e As MouseEventArgs) Handles LinkLabel1.MouseMove
        If LinkLabel1.LinkColor = Color.White Then
            LinkLabel1.LinkColor = Color.Lime
        Else
            LinkLabel1.LinkColor = Color.Lime
        End If

    End Sub

    Private Sub LinkLabel1_MouseLeave(ByVal sender As Object, ByVal e As System.EventArgs) Handles LinkLabel1.MouseLeave
        If LinkLabel1.LinkColor = Color.Lime Then
            LinkLabel1.LinkColor = Color.White
        Else
            LinkLabel1.LinkColor = Color.Lime
        End If
    End Sub

    Private Sub LinkLabel2_MouseMove(ByVal sender As Object, ByVal e As MouseEventArgs) Handles LinkLabel2.MouseMove
        If LinkLabel2.LinkColor = Color.White Then
            LinkLabel2.LinkColor = Color.Lime
        Else
            LinkLabel2.LinkColor = Color.Lime
        End If

    End Sub

    Private Sub LinkLabel2_MouseLeave(ByVal sender As Object, ByVal e As System.EventArgs) Handles LinkLabel2.MouseLeave
        If LinkLabel2.LinkColor = Color.Lime Then
            LinkLabel2.LinkColor = Color.White
        Else
            LinkLabel2.LinkColor = Color.Lime
        End If
    End Sub

    Private Sub LinkLabel3_MouseMove(ByVal sender As Object, ByVal e As MouseEventArgs) Handles LinkLabel3.MouseMove
        If LinkLabel3.LinkColor = Color.White Then
            LinkLabel3.LinkColor = Color.Lime
        Else
            LinkLabel3.LinkColor = Color.Lime
        End If

    End Sub

    Private Sub LinkLabel3_MouseLeave(ByVal sender As Object, ByVal e As System.EventArgs) Handles LinkLabel3.MouseLeave
        If LinkLabel3.LinkColor = Color.Lime Then
            LinkLabel3.LinkColor = Color.White
        Else
            LinkLabel3.LinkColor = Color.Lime
        End If
    End Sub

    Private Sub LinkLabel4_MouseMove(ByVal sender As Object, ByVal e As MouseEventArgs) Handles LinkLabel4.MouseMove
        If LinkLabel4.LinkColor = Color.White Then
            LinkLabel4.LinkColor = Color.Lime
        Else
            LinkLabel4.LinkColor = Color.Lime
        End If

    End Sub

    Private Sub LinkLabel4_MouseLeave(ByVal sender As Object, ByVal e As System.EventArgs) Handles LinkLabel4.MouseLeave
        If LinkLabel4.LinkColor = Color.Lime Then
            LinkLabel4.LinkColor = Color.White
        Else
            LinkLabel4.LinkColor = Color.Lime
        End If
    End Sub

    Private Sub LinkLabel6_MouseMove(ByVal sender As Object, ByVal e As MouseEventArgs)
        If LinkLabel6.LinkColor = Color.White Then
            LinkLabel6.LinkColor = Color.Gray
        Else
            LinkLabel6.LinkColor = Color.Gray
        End If

    End Sub

    Private Sub LinkLabel6_MouseLeave(ByVal sender As Object, ByVal e As System.EventArgs)
        If LinkLabel6.LinkColor = Color.Gray Then
            LinkLabel6.LinkColor = Color.White
        Else
            LinkLabel6.LinkColor = Color.Gray
        End If
    End Sub

    Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Form1.Hide()
    End Sub

    Private Sub LinkLabel4_LinkClicked(ByVal sender As System.Object, ByVal e As System.Windows.Forms.LinkLabelLinkClickedEventArgs) Handles LinkLabel4.LinkClicked
        Form1.Show()
        Me.Close()
    End Sub
    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        Label1.Text = (Label1.Text + 1)
        If Label1.Text > 59 Then
            Label1.Text = "0"
            Label2.Text = (Label2.Text + 1)
        End If

    End Sub

    Private Sub RichTextBox2_KeyDown(ByVal sender As Object, _
    ByVal e As System.Windows.Forms.KeyEventArgs) _
    Handles RichTextBox2.KeyDown
        ' Ao pressionar a tecla Delete eliminamos o elemento selecionado no listbox
        If e.KeyCode = Keys.Space Then
            Label6.Text = Label6.Text + 1
            If (RichTextBox2.Text = "Hoje") Then
                Label4.Text = Label4.Text + 1
            End If
            If (RichTextBox2.Text = "Hoje meu") Then
                Label4.Text = Label4.Text + 1
            End If
            If (RichTextBox2.Text = "Hoje meu dia") Then
                Label4.Text = Label4.Text + 1
            End If
        End If
    End Sub

    Private Sub Timer2_KeyDown(ByVal sender As Object, _
    ByVal e As System.Windows.Forms.KeyEventArgs) _
    Handles RichTextBox2.KeyDown
        ' Ao pressionar a tecla Delete eliminamos o elemento selecionado no listbox
        If e.KeyCode = Keys.Back Then
            Label4.Text = Label4.Text - 1
        End If
    End Sub

    Private Sub Timer2_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer2.Tick

        Label5.Text = RichTextBox2.Text.Length
        Label7.Text = RichTextBox2.Lines.Length

    End Sub

    Private Sub LinkLabel7_LinkClicked(ByVal sender As System.Object, ByVal e As System.Windows.Forms.LinkLabelLinkClickedEventArgs) Handles LinkLabel7.LinkClicked
        Timer1.Stop()
        Timer2.Stop()
    End Sub

    Private Sub LinkLabel6_LinkClicked_1(ByVal sender As System.Object, ByVal e As System.Windows.Forms.LinkLabelLinkClickedEventArgs) Handles LinkLabel6.LinkClicked
        Timer1.Start()
        Timer2.Start()
        RichTextBox2.ReadOnly = False
    End Sub

    Private Sub LinkLabel8_LinkClicked(ByVal sender As System.Object, ByVal e As System.Windows.Forms.LinkLabelLinkClickedEventArgs) Handles LinkLabel8.LinkClicked
        Voice = CreateObject("SAPI.SpVoice")
        Voice.speak(RichTextBox1.Text)
    End Sub

    Private Sub Label4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Label4.Click

    End Sub

    Private Sub Label8_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Label8.Click

    End Sub

    Private Sub RichTextBox2_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles RichTextBox2.TextChanged

    End Sub
End Class

PS: Oque estou fazendo é uma espécie de "curso de digitação"

Editado Maio 14, 2012 por nando.m