Open word document in RichtextBox using VB.net

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

        Dim op1 As OpenFileDialog = New OpenFileDialog() With {

            .ValidateNames = True,

            .Multiselect = False,

            .Filter = "Word|*.doc;*.docx"

                }

        If op1.ShowDialog() = DialogResult.OK Then

            Dim readonly1 As Object = True

            Dim visible As Object = True

            Dim save As Object = True

            Dim filename As Object = op1.FileName

            Dim missing As Object = Type.Missing

            Dim template As Object = False

            Dim typedoc As Object = 0

            Dim doc1 As Microsoft.Office.Interop.Word._Document = Nothing

            Dim word1 As Microsoft.Office.Interop.Word._Application = New Microsoft.Office.Interop.Word.Application() With {

              .Visible = False

            }

            doc1 = word1.Documents.Open(filename, readonly1, visible)

            doc1.ActiveWindow.Selection.WholeStory()

            doc1.ActiveWindow.Selection.Copy()

            Dim data1 As IDataObject = Clipboard.GetDataObject

            RichTextBox1.Rtf = data1.GetData(DataFormats.Rtf).ToString

            word1.Quit(missing)

        End If

End Sub