How can i get selected file path in asp.netc#.

I am uploading my file through "FileUpload" Control using ASP.Net,C#. My requirements is that if a user select a file for upload, i want to know the path of that selected file because i want to read it through StreamReader. 

StreamReader sourceStream = new StreamReader(userFileFullPath);

then i want to write it on FTP using following code.

  byte[] fileContents = Encoding.UTF8.GetBytes(sourceStream.ReadToEnd());

        sourceStream.Close();
        request.ContentLength = fileContents.Length;
        Stream requestStream = request.GetRequestStream();
        requestStream.Write(fileContents, 0, fileContents.Length);
        requestStream.Close();
        FtpWebResponse response = (FtpWebResponse)request.GetResponse();
        lblMessage.Text = response.StatusDescription;
        response.Close();

How can i get the selected file path of user in asp.net,c#. Please suggest me.