Window Form C#

Table Creation

Create table employee(empid varchar(50) primary key,empname varchar(50),sal int)

Default.aspx code

<%@ Page Language="C#" AutoEventWireup="true"  CodeFile="Default.aspx.cs" Inherits="_Default" %>





   


   

   

   
                    Width="100px">
   

   
   

   
   

   

   
            Text="Insert Data" />

   
   
   



Default.aspx.cs code

using System;
using System.Configuration;
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;
public partial class _Default : System.Web.UI.Page
{
    string strConnString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
    string str;
    SqlCommand com;
    int count;
    protected void Page_Load(object sender, EventArgs e)
    {
        SqlConnection con = new SqlConnection(strConnString);
        str = "select count(*) from employee";
        com = new SqlCommand(str, con);
        con.Open();
        count = Convert.ToInt16(com.ExecuteScalar()) + 1;
        txt_empid.Text = "E00" + count;
        con.Close();
    }
    protected void btn_insert_Click(object sender, EventArgs e)
    {
        SqlConnection con = new SqlConnection(strConnString);
        con.Open();
        str = "insert into employee values('" + txt_empid.Text.Trim() + "','" + txt_empname.Text.Trim() + "'," + txt_sal.Text.Trim() + ")";
        com = new SqlCommand(str, con);
        com.ExecuteNonQuery();
        con.Close();
        Label4.Text = "Records successfully Inserted";
    }
}

make first connection to database 
oledbconnection con=new oledbconnection(string connection);
con.open();
oledbcommand cmd=new oledbcommand("select max(regno) from table",con)
oledbdatareader dr=cmd.executereader();
while(dr.read()==true)
{
text1.text=dr["regno"].tostring();
}
read it in form load gives u autoincremented result