How to Bind State Wise Citylist in DropDownList in ASP.NET

Here I am going to explain how to show state wise city list  in DropDownList in Asp.net like below Image.

 

I have two tables in database like :

Now write the below code On the Page_Load in Asp.net

protected void Page_Load(object sender, EventArgs e)

{
    SqlConnection cn = new SqlConnection("Data Source=BCILGGN13\\SQLEXPRESS;Initial   catalog=Test; Uid=sa; Pwd=bcil;");
    DataTable dt;
    DataTable dt1;
    SqlDataAdapter adap;
    if (!IsPostBack)
    {
        ddlCity.AppendDataBoundItems = true;
        ddlCity.Items.Insert(0, "-select-");
        adap = new SqlDataAdapter("select * from State_List", cn);
        dt = new DataTable();
        adap.Fill(dt);
        int j = 0;
        if (dt.Rows.Count > 0)
        {
            j = 1;
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                ddlCity.Items.Add(dt.Rows[i]["State"].ToString());
                ddlCity.Items[j].Attributes.Add("style", "color:red");
                adap = new SqlDataAdapter("select City from city_list where state= '" + dt.Rows[i]["State"] + "'", cn);
                dt1 = new DataTable();
                adap.Fill(dt1);
                for (int k = 0; k < dt1.Rows.Count; k++)
                {
                    ddlCity.Items.Add(dt1.Rows[k]["City"].ToString());
                }
              j = dt1.Rows.Count +j+1;
            }
        }
    }
}