BUSCAR Y REEMPLAZAR EN VB .NET

LLAMAR AL FORMULARIO

Private Sub SubIndiceButton2_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles SubIndiceButton2.Click
        frmReplace.Show()
End Sub

    Private Sub btnbuscar_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnbuscar.Click

        Dim StartPosition As Integer
        Dim SearchType As CompareMethod

        StartPosition = InStr(1, Form1.RichTextBox1.Text, txtbuscar.Text, SearchType)

        If StartPosition = 0 Then
            MessageBox.Show("Palabra: '" & txtbuscar.Text.ToString() & "'No encontrada", "Búsqueda en el documento", MessageBoxButtons.OK, MessageBoxIcon.Asterisk)
            Exit Sub
        End If

        form1.richtextbox1.Select(StartPosition - 1, txtbuscar.Text.Length)
        form1.richtextbox1.ScrollToCaret()
        Form1.Focus()


    End Sub



    Private Sub btnbuscarsiguiente_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnbuscarsig.Click

        Dim StartPosition As Integer = form1.richtextbox1.SelectionStart + 2
        Dim SearchType As CompareMethod

        StartPosition = InStr(StartPosition, Form1.RichTextBox1.Text, txtbuscar.Text, SearchType)

        If StartPosition = 0 Then
            MessageBox.Show("Palabra: '" & txtbuscar.Text.ToString() & "' No encontrada", "Búsqueda en el documento", MessageBoxButtons.OK, MessageBoxIcon.Asterisk)
            Exit Sub
        End If

        Form1.RichTextBox1.Select(StartPosition - 1, txtbuscar.Text.Length)
        Form1.RichTextBox1.ScrollToCaret()
        Form1.Focus()

    End Sub



    Private Sub btnReemplazar_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnReemplazar.Click

        If form1.richtextbox1.SelectedText.Length <> 0 Then
            form1.richtextbox1.SelectedText = txtreemplazar.Text
        End If

        Dim StartPosition As Integer = form1.richtextbox1.SelectionStart + 2
        Dim SearchType As CompareMethod

        StartPosition = InStr(StartPosition, Form1.RichTextBox1.Text, txtbuscar.Text, SearchType)

        If StartPosition = 0 Then
            MessageBox.Show("Palabra: '" & txtbuscar.Text.ToString() & "' No encontrada", "Búsqueda en el documento", MessageBoxButtons.OK, MessageBoxIcon.Asterisk)
            Exit Sub
        End If

        form1.richtextbox1.Select(StartPosition - 1, txtbuscar.Text.Length)
        form1.richtextbox1.ScrollToCaret()
        Form1.Focus()

    End Sub



    Private Sub btnReemplazartodo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnReemplazartodo.Click


        Dim currentPosition As Integer = form1.richtextbox1.SelectionStart
        Dim currentSelect As Integer = form1.richtextbox1.SelectionLength

        form1.richtextbox1.Rtf = Replace(form1.richtextbox1.Rtf, Trim(txtbuscar.Text), Trim(txtreemplazar.Text))
        form1.richtextbox1.SelectionStart = currentPosition
        form1.richtextbox1.SelectionLength = currentSelect

        Form1.Focus()

    End Sub