Populated textbox problem

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

public partial class FinancialProfileFormA : System.Web.UI.Page
{

    protected void Page_Load(object sender, EventArgs e)
    {
       
    }
    protected void ButtonSubmit_Click(object sender, EventArgs e)
    {

        SqlConnection con = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["PassConnectionString"].ConnectionString);
        


        SqlCommand cmd = new SqlCommand ("Insert into TableFIN (TOTAL_REVE, INSTRUCTIO, RESEARCH, PUBLIC_SER, ACADEMIC_S, STUDENT_SE, INSTITUTIO, PHYSICAL_P, SCHOLARSHI, AUXILIARY_, HOSPITALS, INDEPENDEN, OTHEREXP, TOTASSETS, TOTLIABILITY, NoNEXPPERMRESASSETS, UNRNETASSETS, TOTALREV, TUITFEES, CURRDEBT, LONGTERMDEBT) values (@TOTAL_REVE, @INSTRUCTIO, @RESEARCH, @PUBLIC_SER, @ACADEMIC_S, @STUDENT_SE, @INSTITUTIO, @PHYSICAL_P, @SCHOLARSHI, @AUXILIARY_, @HOSPITALS, @INDEPENDEN, @OTHEREXP, @TOTASSETS, @TOTLIABILITY, @NoNEXPPERMRESASSETS, @UNRNETASSETS, @TOTALREV, @TUITFEES, @CURRDEBT, @LONGTERMDEBT)",con);
        
        cmd.CommandType = CommandType.Text;
        cmd.Parameters.AddWithValue("@TOTAL_REVE", TextBoxTROA.Text);
        cmd.Parameters.AddWithValue("@INSTRUCTIO", TextBoxInstr.Text);
        cmd.Parameters.AddWithValue("@RESEARCH", TextBoxRes.Text);
        cmd.Parameters.AddWithValue("@PUBLIC_SER", TextBoxPubS.Text);
        cmd.Parameters.AddWithValue("@ACADEMIC_S", TextBoxAcad.Text);
        cmd.Parameters.AddWithValue("@STUDENT_SE", TextBoxStudS.Text);
        cmd.Parameters.AddWithValue("@INSTITUTIO", TextBoxInstiS.Text);
        cmd.Parameters.AddWithValue("@PHYSICAL_P", TextBoxOperM.Text);
        cmd.Parameters.AddWithValue("@SCHOLARSHI", TextBoxSFEDA.Text);
        cmd.Parameters.AddWithValue("@AUXILIARY_", TextBoxAuxE.Text);
        cmd.Parameters.AddWithValue("@HOSPITALS", TextBoxHosS.Text);
        cmd.Parameters.AddWithValue("@INDEPENDEN", TextBoxIndeO.Text);
        cmd.Parameters.AddWithValue("@OTHEREXP", TextBoxOED.Text);
        cmd.Parameters.AddWithValue("@TOTASSETS", TextBoxTA.Text);
        cmd.Parameters.AddWithValue("@TOTLIABILITY", TextBoxTL.Text);
        cmd.Parameters.AddWithValue("@NoNEXPPERMRESASSETS", TextBoxNPRNA.Text);
        cmd.Parameters.AddWithValue("@UNRNETASSETS", TextBoxTUNA.Text);
        cmd.Parameters.AddWithValue("@TOTALREV", TextBoxTR.Text);
        cmd.Parameters.AddWithValue("@TUITFEES", TextBoxTFN.Text);
        cmd.Parameters.AddWithValue("@CURRDEBT", TextBoxCD.Text);
        cmd.Parameters.AddWithValue("@LONGTERMDEBT", TextBoxLTD.Text);

        con.Open();
        cmd.ExecuteNonQuery();
        }

   public class PCPrint : System.Drawing.Printing.PrintDocument
    {
        
    }

   protected void ButtonPrint_Click(object sender, EventArgs e)
   {
       
   }

   protected void DropDownListSchool_SelectedIndexChanged(object sender, EventArgs e)
   {
       DataTable dt = new DataTable();
       SqlConnection connection = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["PassConnectionString"].ConnectionString);
       connection.Open();
       SqlCommand sqlCmd = new SqlCommand("SELECT * from TableFIN WHERE INST_ID = @", connection);
       SqlDataAdapter sqlDa = new SqlDataAdapter(sqlCmd);


       
       sqlDa.Fill(dt);
       if (dt.Rows.Count > 0)
       {
           TextBoxLYTA.Text = dt.Rows[0]["TOTASSETS"].ToString();
           TextBoxLYTL.Text = dt.Rows[0]["TOTLIABILITY"].ToString();
           TextBoxLYNPRNA.Text = dt.Rows[0]["NONEXPPERMRESASSETS"].ToString();

       }
       connection.Close();
   }
   protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
   {

   }
}