protected void UploadFile(object sender, EventArgs e)
    {
        string filename = Path.GetFileName(FileUpload1.PostedFile.FileName);
        string contentType = FileUpload1.PostedFile.ContentType;
        using (Stream fs = FileUpload1.PostedFile.InputStream)
        {
            using (BinaryReader br = new BinaryReader(fs))
            {
                byte[] bytes = br.ReadBytes((Int32)fs.Length);
                string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
                using (MySqlConnection con = new MySqlConnection(constr))
                {
                    string query = "INSERT INTO foto(FileName, ContentType, Content, IdAlerta) VALUES (@FileName, @ContentType, @Content)";
                    using (MySqlCommand cmd = new MySqlCommand(query))
                    {
                        cmd.Connection = con;
                        cmd.Parameters.AddWithValue("@FileName", filename);
                        cmd.Parameters.AddWithValue("@ContentType", contentType);
                        cmd.Parameters.AddWithValue("@Content", bytes);
                        con.Open();
                        cmd.ExecuteNonQuery();
                        con.Close();
                    }
                }
            }
        }
        Response.Redirect(Request.Url.AbsoluteUri);
    }