String or binary data would be truncated. ปัญหาการ post ในเว็บบอร์ดครับ แปลกมากๆ ใครเคยเจอปัญหานี้ช่วยแนะนำด้วยครับ

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Text;
using System.Data;
using System.Data.SqlClient;
using System.Web.Configuration;

namespace Webboard
{
    public partial class Reply : System.Web.UI.Page
    {
        string CurrentTID = "";
 
        protected void Page_Load(object sender, EventArgs e)
        {
            CurrentTID = Request.QueryString["TID"];
            if (CurrentTID == null)
            {
                Response.Redirect("Default.aspx");
            }
            else
            {
                if (CurrentTID == "")
                {
                    Response.Redirect("Default.aspx");
                }
                else
                {
                    string strConn;
                    strConn = WebConfigurationManager.ConnectionStrings["WebboardConnectionString"].ConnectionString;
                    SqlConnection Conn = new SqlConnection(strConn);
                    Conn.Open();

                    StringBuilder sb = new StringBuilder();
                    sb.Append("SELECT TID,Description,UserName,RecordDate,ViewCount,ReplyCount");
                    sb.Append(" FROM Topic");
                    sb.Append(" WHERE TID=@TID");
                    var sqlTopic = sb.ToString();

                    SqlCommand com = new SqlCommand();
                    com.Connection = Conn;
                    com.Parameters.Clear();
                    com.Parameters.Add("@TID", SqlDbType.NVarChar).Value = CurrentTID;
                    com.CommandType = CommandType.Text;
                    com.CommandText = sqlTopic;
                    var dr = com.ExecuteReader();
                    if (dr.HasRows)
                    {
                        dr.Read();
                        var Description = dr.GetString(dr.GetOrdinal("Description"));
                        var UserName = dr.GetString(dr.GetOrdinal("UserName"));
                        var RecordDate = dr.GetDateTime(dr.GetOrdinal("RecordDate"));
                        var ViewCount = dr.GetInt32(dr.GetOrdinal("ViewCount"));
                        dr.Close();

                        sb.Clear();
                        sb.Append("UPDATE Topic");
                        sb.Append(" SET ViewCount=@ViewCount");
                        sb.Append(" WHERE (TID=@TID)");
                        var sqlUpdate = sb.ToString();
                        com.Parameters.Clear();
                        com.Parameters.Add("@ViewCount", SqlDbType.Int).Value = ViewCount + 1;
                        com.Parameters.Add("@TID", SqlDbType.NVarChar).Value = CurrentTID;
                        com.CommandText = sqlUpdate;
                        com.ExecuteNonQuery();

                        Response.Write("<a href='Default.aspx' font-underline='#false'>กลับสู่เว็บบอร์ด</a><br /><br />");
                        Response.Write("<table style='width:960px;'border='0'>");
                        Response.Write("<tr><td colspan='3' bgcolor='#FFCCCC'>" + "หัวข้อกระทู้ : " + Description + "</td></tr>");
                        Response.Write("<tr><td bgcolor='#FFCCCC'>" + "จากคุณ : " + UserName + "</td>");
                        Response.Write("<td bgcolor='#FFCCCC'>" + "วันที่ตั้งกระทู้ : " + RecordDate + "</td></tr></table>");
                    }
                    dr.Close();
                }
            }
        }

        protected void cmdSave_Click(object sender, EventArgs e)
        {
            string strConn;
            strConn = WebConfigurationManager.ConnectionStrings["WebboardConnectionString"].ConnectionString;
            SqlConnection Conn = new SqlConnection(strConn);
            Conn.Open();

            StringBuilder sb = new StringBuilder();
            sb.Append("SELECT TOP 1 ReplyNO FROM Reply");
            sb.Append(" WHERE TID=@TID");
            sb.Append(" ORDER BY ReplyNO Desc");
            var sqlSave = sb.ToString();

            int LastReplyNO;
            SqlCommand com = new SqlCommand();
            SqlDataReader dr;
            com.Connection = Conn;
            com.Parameters.Clear();
            com.Parameters.Add("@TID", SqlDbType.NVarChar).Value = CurrentTID;
            com.CommandType = CommandType.Text;
            com.CommandText = sqlSave;
            dr = com.ExecuteReader();
            if (dr.HasRows)
            {
                dr.Read();
                var CurrentReplyNO = dr.GetInt32(0);
                CurrentReplyNO++;
                LastReplyNO = CurrentReplyNO;
            }
            else
            {
                LastReplyNO = 1;
            }
            dr.Close();

            sb.Clear();
            sb.Append("INSERT INTO Reply(TID,ReplyNO,Description,ReplyName,ReplyDate,IP)");
            sb.Append("VALUES (@TID,@ReplyNo,@Description,@ReplyName,@ReplyDate,@IP)");
            sqlSave = sb.ToString();
            com.CommandText = sqlSave;
            com.Parameters.Clear();
            com.Parameters.Add("@TID", SqlDbType.NVarChar).Value = CurrentTID;
            com.Parameters.Add("@ReplyNO", SqlDbType.NVarChar).Value = LastReplyNO;
            com.Parameters.Add("@Description", SqlDbType.NVarChar).Value = txtDescription.Text.Trim();
            com.Parameters.Add("@ReplyName", SqlDbType.NVarChar).Value = txtReplyName.Text.Trim();
            com.Parameters.Add("@ReplyDate", SqlDbType.DateTime).Value = DateTime.Now;
            com.Parameters.Add("@IP", SqlDbType.NVarChar).Value = Request.ServerVariables["REMOTE_ADDR"];
            com.ExecuteNonQuery();

            sb.Clear();
            sb.Append("UPDATE Topic");
            sb.Append(" SET ReplyCount=@ReplyCount");
            sb.Append(" WHERE (TID=@TID)");
            var sqlUpdate = sb.ToString();
            com.Parameters.Clear();
            com.Parameters.Add("@ReplyCount", SqlDbType.Int).Value = LastReplyNO;
            com.Parameters.Add("@TID", SqlDbType.NVarChar).Value = CurrentTID;
            com.CommandText = sqlUpdate;
            com.ExecuteNonQuery();

            Conn.Close();
            Response.Redirect("Default.aspx");
        }

        protected void cmdClear_Click(object sender, EventArgs e)
        {
            txtDescription.Text = "";
            txtReplyName.Text = "";
        }
    }
}