FTP UPLOAD

I want to upload image from client machine to webserver using FileUpload control via using FtpWebRequest class but when i want to create a object of that class it created but it throw exeption (ftpReq.PreAuthenticate' threw an exception of type 'System.NotSupportedException'
'ftpReq.ContentType' threw an exception of type 'System.NotSupportedException')
i am giving complete code
 public string upload(string fileName)
        {
        
            FileInfo info = new FileInfo(fileName);
            string uri = "ftp://xyz.in/Uploadfolder/" + info.Name;
            FtpWebRequest ftpReq;
            ftpRe ...