Display conditional JavaScript Alert Message Box based on value from Database in ASP.Net

on this page i am checking whether the username,password,wardno,electionid are matching with the one in DB.

if they are matching then i am checking whether the stat is voted.

if it is voted then i am giving a alert message that you have already voted.

if they(username,password,wardno,electionid) are not matching then i am giving a alert message "invalid entry".

i am having a user named krishna

he has already voted

so instead of showing you have already voted it is showing invalid entry.

please tel the necessary changes to be done

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

public partial class signin : System.Web.UI.Page
{
    SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString);
    protected void Page_Load(object sender, EventArgs e)
    {
        con.Open();
    }
    protected void ImageButton1_Click(object sender, ImageClickEventArgs e)
    {
        
        SqlCommand cmd = new SqlCommand("select * from users", con);
        cmd.ExecuteNonQuery();

        SqlDataReader reader = cmd.ExecuteReader();
        while (reader.Read())
        {
            string uname = reader["UserName"].ToString();
            string pwd = reader["Password"].ToString();
            string wno = reader["WardNo"].ToString();
            string eid = reader["ElectionId"].ToString();
            string stat = reader["Status"].ToString();
            if (uname == TextBox1.Text && pwd == TextBox2.Text && eid == TextBox3.Text && wno == DropDownList1.Text)
            {
                Session["name"] = TextBox1.Text;
                Session["pass"] = TextBox2.Text;
              
                if (stat == "Voted")
                {
                    string script = "window.onload = function() { alert('You Have Already Voted!'); }";
                    ClientScript.RegisterStartupScript(this.GetType(), "alert", script, true);
                    
                }
                else if (DropDownList1.Text == "171")
                {
                    Response.Redirect("wardno171.aspx?ab=" + TextBox3.Text);
                }
                else
                {
                    Response.Redirect("wardno180.aspx?ab=" + TextBox3.Text);
                }
            }
               else 
             
             {
                 string script = "window.onload = function() { alert('Invalid Entry!'); }";
                 ClientScript.RegisterStartupScript(this.GetType(), "alert", script, true);
             }
        }
    }
}