im trying to genrate id asp.net using c# in access databse

Question

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Data.OleDb;

using System.IO;

using System.Data;

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

{

OleDbConnection con;

OleDbCommand com;

string str;

public admin_AddminItem()

{

new_id();

}

protected void Page_Load(object sender, EventArgs e)

{

}

private void new_id()

{

if (con.State != ConnectionState.close)

{

con.Open();

}

str = "select max(admin_create_id) from Itm_tbl";

com = new OleDbCommand(str, con);

com.CommandType = CommandType.Text;

Int32 max = (Int32)com.ExecuteScalar();

Label3.Text = (max + 1).ToString();

con.Close();

}

protected void Button9_Click(object sender, EventArgs e)

{

if (con.State == ConnectionState.Closed)

{

{

con.Open();

}

con = new OleDbConnection(@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=F:\ahb\Desktop1\App_Data\amit_db.mdb");

string str = FileUpload1.FileName;

FileUpload1.PostedFile.SaveAs(Server.MapPath("~/Upload/" + str));

string Image = "~/Upload/" + str.ToString();

string cat_name = DropDownList1.SelectedValue.ToString();

OleDbCommand cmd = new OleDbCommand("insert into Itm_tbl values(@admin_create_id, @name , @desc , @price , @qty , @img , @cat )", con);

com.Parameters.AddWithValue("@admin_create_id", Label3.Text);

cmd.Parameters.AddWithValue("@name",txtiname.Text );

cmd.Parameters.AddWithValue("@desc",txtdescrip.Text );

cmd.Parameters.AddWithValue("@price",int.Parse(txtprice.Text) );

cmd.Parameters.AddWithValue("@qty", int.Parse(txtquan.Text));

cmd.Parameters.AddWithValue("@img",Image );

cmd.Parameters.AddWithValue("@cat",cat_name );

con.Open();

cmd.ExecuteNonQuery();

con.Close();

Label1.Text = "Item added";

Label1.ForeColor = System.Drawing.Color.ForestGreen;

new_id();

}

else

{

Label1.Text = "Please Upload your Image";

Label1.ForeColor = System.Drawing.Color.Red;

}

}

protected void txtdescrip_TextChanged(object sender, EventArgs e)

{

}

}