how to solved Could not load type 'csvfileupload2.Autocomple

how to solved bellow maintain error

Errror: Could not load type 'csvfileupload2.Autocomplete_demo.

my code Autocomplete_demo.aspx.cs is bellow

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Data;

using System.Data.SqlClient;

using System.Configuration;

using System.Web.Services;

namespace csvfileupload2

{

public partial class Autocomplete_demo : System.Web.UI.Page

{

public object prefixText { get; set; }

protected void Page_Load(object sender, EventArgs e)

{

}

public static List getdata(string prefixText)

{

string str = "Data Source=ANIRUDDHA-PC;Initial Catalog=sark;Integrated Security=True";

SqlConnection con = new SqlConnection(str);

con.Open();

SqlCommand cmd = new SqlCommand("select * from frofilerr where name like @name+'%'", con);

cmd.Parameters.AddWithValue("@name", prefixText);

//cmd.Parameters.AddWithValue("@city",);

SqlDataAdapter sda = new SqlDataAdapter(cmd);

DataTable dt = new DataTable();

sda.Fill(dt);

List name = new List();

for (int i = 0; i < dt.Rows.Count; i++)

{

name.Add(dt.Rows[i][1].ToString());

}

return name;

}

protected void TextBox1_TextChanged(object sender, EventArgs e)

{

}

and my Autocomplete_demo.aspx code is bellow:

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Autocomplete_demo.aspx.cs" Inherits="csvfileupload2.Autocomplete_demo" %>

	AutoComplete TextBox using Ajax AutoCompleteExtender

	style="font-weight: 700" Text="Search Your Name here">

please help me