Public Class Form1
 
    Private Sub Checkboxen _
                                (ByVal sender As System.Windows.Forms.CheckBox, _
                                 ByVal e As System.EventArgs) _
 _
                                 Handles CheckBox1.CheckedChanged, _
                                         CheckBox2.CheckedChanged, _
                                         CheckBox3.CheckedChanged, _
        CheckBox4.CheckedChanged, _
        CheckBox5.CheckedChanged, _
        CheckBox6.CheckedChanged, _
        CheckBox7.CheckedChanged, _
        CheckBox8.CheckedChanged, _
        CheckBox9.CheckedChanged, _
        CheckBox10.CheckedChanged, _
        CheckBox11.CheckedChanged, _
        CheckBox12.CheckedChanged, _
        CheckBox13.CheckedChanged, _
        CheckBox14.CheckedChanged, _
        CheckBox15.CheckedChanged, _
        CheckBox16.CheckedChanged, _
        CheckBox17.CheckedChanged, _
        CheckBox18.CheckedChanged, _
        CheckBox19.CheckedChanged, _
        CheckBox20.CheckedChanged, _
        CheckBox21.CheckedChanged, _
        CheckBox22.CheckedChanged, _
        CheckBox23.CheckedChanged, _
        CheckBox24.CheckedChanged, _
        CheckBox25.CheckedChanged, _
        CheckBox26.CheckedChanged, _
        CheckBox27.CheckedChanged, _
        CheckBox28.CheckedChanged, _
        CheckBox29.CheckedChanged
 
        Dim cb As CheckBox = CType(sender, CheckBox)
 
        Dim str As String = cb.Text
 
        If cb.Checked Then
            RichTextBox1.AppendText(str & vbNewLine)
 
        Else
            With RichTextBox1
                Dim pos As Integer = .Find(str, 0, RichTextBoxFinds.MatchCase)
                If pos >= 0 Then
                    .SelectionStart = pos
                    .SelectionLength = str.Length + 1
                    .SelectedText = String.Empty
 
 
                End If
            End With
        End If
End Class
 
    End Sub