文本框中的值没有插入数据库c#

    protected void Page_Load(object sender, EventArgs e)
    {
        if (!this.IsPostBack)
        {
            if (Request.InputStream.Length > 0)
            {
                using (StreamReader reader = new StreamReader(Request.InputStream))
                {
                    string hexString = Server.UrlEncode(reader.ReadToEnd());
                    string imageName = DateTime.Now.ToString("dd-MM-yy hh-mm-ss");
                    string imagePath = string.Format("~/losefound/{0}.png", imageName);
                    string ItemName = txtItemName.Text;
                    string Place = txtPlace.Text;
                    byte[] bytes = ConvertHexToBytes(hexString);
                    File.WriteAllBytes(Server.MapPath(imagePath), bytes);
                    string VisitorManagementConnectionString = ConfigurationManager.ConnectionStrings["VisitorManagementConnectionString"].ConnectionString;
                    using (SqlConnection con = new SqlConnection(VisitorManagementConnectionString))
                    {
                        string query = "INSERT INTO LostFound (ItemName, FoundAt, TimeIn, ImageName, ContentType, Data) VALUES(@ItemName, @FoundAt, @TimeIn, @ImageName, @ContentType, @Data);SELECT SCOPE_IDENTITY()";
                        using (SqlCommand cmd = new SqlCommand(query))
                        {
                            cmd.Connection = con;
                            cmd.Parameters.AddWithValue("@ItemName", ItemName);
                            cmd.Parameters.AddWithValue("@FoundAt", Place);
                            cmd.Parameters.AddWithValue("@TimeIn", DateTime.Now);
                            cmd.Parameters.AddWithValue("@ImageName", imageName);
                            cmd.Parameters.AddWithValue("@ContentType", "image/png");
                            cmd.Parameters.AddWithValue("@Data", bytes);
                            con.Open();
                            Session["CapturedImageId"] = cmd.ExecuteScalar();
                            con.Close();
                        }
                    }
                }
            }
        }
    }
    private static byte[] ConvertHexToBytes(string hex)
    {
        byte[] bytes = new byte[hex.Length / 2];
        for (int i = 0; i < hex.Length; i += 2)
        {
            bytes[i / 2] = Convert.ToByte(hex.Substring(i, 2), 16);
        }
        return bytes;
    }
    [WebMethod(EnableSession = true)]
    public static string GetCapturedImage()
    {
        string url = string.Empty;
        int imageId = Convert.ToInt32(HttpContext.Current.Session["CapturedImageId"]);
        string VisitorManagementConnectionString = ConfigurationManager.ConnectionStrings["VisitorManagementConnectionString"].ConnectionString;
        using (SqlConnection con = new SqlConnection(VisitorManagementConnectionString))
        {
            using (SqlCommand cmd = new SqlCommand())
            {
                cmd.CommandText = "SELECT Data FROM LostFound WHERE Id = @Id";
                cmd.Parameters.AddWithValue("@Id", imageId);
                cmd.Connection = con;
                con.Open();
                byte[] bytes = (byte[])cmd.ExecuteScalar();
                url = "data:image/png;base64," + Convert.ToBase64String(bytes, 0, bytes.Length);
                con.Close();
            }
        }
        HttpContext.Current.Session["CapturedImageId"] = null;
        return url;
    }
    protected void btnCapture_Click(object sender, EventArgs e)
    {
    }
}

文本框中的值从未插入到数据库中。只有datetime。现在，可以插入imageName、contentType和data了。应该在btncapture中插入文本框查询吗?

有人可以引导我哪里我错了?