ASP.Net 1.1 如何上传文件

ASP.Net 1.1 没有.Net2.0提供的FileUpload控件，需要添加一个type为file的html input控件，然后再写一个
独立的upload button。实例如下：
1. HTML
  <input id="txtAttch" type="file" runat="server">
<br>
<input id="cmdUpload" type="button" value="Upload" runat="server">
2. Server
    Private Sub cmdUpload_ServerClick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdUpload.ServerClick
        Dim cFile As String
        Dim cFileName As String
        Dim cServerFilePath As String = Server.MapPath("") & "\MailAttachments\"
        cFile = Me.txtAttch.PostedFile.FileName
        cFileName = System.IO.Path.GetFileName(cFile)
        cServerFilePath = cServerFilePath & cFileName
        Me.txtAttch.PostedFile.SaveAs(cServerFilePath)
        PopMsg("Upload Finish")
    End Sub