Add folder to save path on file upload and only allow certain file types

Hi I have a file uploader I would like to be able to have a folder added to the folder path on upload based on a textbox.text "MapPath("~/Uploads/" + Path.GetFileName(e.filename))"
I have Dim folder as String = textbox.text how do I add folder to MapPath("~/Uploads/"
  it currently checks for .xml files how can I add more .doc .gif etc
 
Dim savePath As String = MapPath("~/Uploads/" + Path.GetFileName(e.filename)) 'Validation for file extension If Path.GetExtension(e.filename).Contains(".xml") Then Return End If
 
thanks
 
M
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