Like operator is not work in asp.net vb project

<table border="1" width="80%><br" mode="hold" />  <tr>
    <td>ID</td>
    <td>extension</td>
    <td>Class</td>
  </tr>
  <tr>
    <td>1</td>
    <td>.jpg</td>
    <td>image</td>
  </tr>
  <tr>
    <td>2</td>
    <td>.png</td>
    <td>image</td>
  </tr>
  <tr>
    <td>3</td>
    <td>.gif</td>
    <td>image</td>
  </tr>
  <tr>
    <td>4</td>
    <td>.bmp</td>
    <td>image</td>
  </tr>
  <tr>
    <td>5</td>
    <td>.avi</td>
    <td>video</td>
  </tr>
  <tr>
    <td>6</td>
    <td>.mp4</td>
    <td>video</td>
  </tr>
  <tr>
    <td>7</td>
    <td>.mp3</td>
    <td>audio</td>
  </tr>
  <tr>
    <td>8</td>
    <td>.wma</td>
    <td>audio</td>
  </tr>
</table>

<asp:DropDownList ID="DropDownList1" runat="server">
     <asp:ListItem>image</asp:ListItem>
     <asp:ListItem>video</asp:ListItem>
     <asp:ListItem>audio</asp:ListItem>
</asp:DrpDownList>

<asp:FileUpload ID="FileUpload1" runat="server" />

<asp:Button ID="Button1" runat="server" Text="Upload" />

con.connecton()

con.query("select * from tbl_extension where Class='" & DropDownList1.SelectedItem.ToString & "' ")

While con.Reader.Read()

If FileUpload1.FileName Like "*" & con.Reader("extension").toString then

     FileUpload1.PostedFile.SaveAs("c:\test\")

     EndIf

End While

con.Reader.Close()

If FileUpload1.FileName Like "*.jpg" then

          FileUpload1.PostedFile.SaveAs("c:\test\")

EndIf