Automatically Generate the number and incremented in TextBox Field in C# and ASP.NET

// automatically generate the number and incremented in TextBox Field (C# and ASP.NET)

From Above Form,   " Praposal Number " TextBox field is automatically generate number incrementally in everytime process like 001,002.....so on.

                         

The Code is Shown Below...

using System.Data;

using System.Linq;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.HtmlControls;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Xml.Linq;

using System.Data.SqlClient;

protected void Page_Load(object sender, EventArgs e)
{
con.Open();
        SqlCommand cmd = new SqlCommand("SELECT COUNT(ProposalNumber) as Tot FROM Proposals", con);

        SqlDataReader dr;

        dr = cmd.ExecuteReader();
        while (dr.Read())
        {
            int i = Convert.ToInt32(dr["tot"]);

            if (i > 0)
            {
                int j = i + 1;
                TextBox1.Text = "00" + j.ToString();

            }
            else
            {
                TextBox1.Text = "00";
            }

        }
        con.Close();

}