Uploading files in ASP.Net C#

protected void FileUploadLABMinutes_Load(object sender, AjaxControlToolkit.AsyncFileUploadEventArgs e)
    {
        lblMessage.ForeColor = System.Drawing.Color.Red;
        if (FileUploadLABMinutes.HasFile)
        {
            try
            {

                string filename = FileUploadLABMinutes.FileName;

                Session["Filename"] = filename;
                string extension = filename.Substring(filename.LastIndexOf('.') + 1);
                if (extension == "pdf")
                {
                    lblMessage.ForeColor = System.Drawing.Color.Blue;
                    string path = Server.MapPath("Upload/") + FileUploadLABMinutes.FileName;
                    FileUploadLABMinutes.SaveAs(path);

                    lblMessage.Text = "File uploaded successfully!";

                }
                else
                    lblMessage.Text = "Upload status: Only pdf files are accepted!";
            }
            catch (Exception ex)
            {
                lblMessage.Text = "Upload status: The file could not be uploaded. The following error occured: " + ex.Message;
            }
        }
        else
        {
            lblMessage.Text = "Please select a file to upload.";
        }
    }
    protected void btnUpload_Click(object sender, EventArgs e)
    {


        string path = Server.MapPath("Upload/") + FileUploadLABMinutes.FileName;

        ShowPdf1.FilePath = "Upload/" + FileUploadLABMinutes.FileName;
        ShowPdf1.DataBind();

        HyperLink1.NavigateUrl = "Upload/" + FileUploadLABMinutes.FileName;