Insert items to database and display it within a dropdown list after adding

In this blog we will know how to insert items to database and display it within a dropdown list after adding those items simultaneously.


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

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:Label ID="Label1" runat="server" Text="Name" Width="100px"></asp:Label>
        <asp:TextBox ID="txt_name" runat="server"></asp:TextBox>
        <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server"
            ControlToValidate="txt_name" ErrorMessage="Please insert name"></asp:RequiredFieldValidator>
        <br />
        <asp:Button ID="btn_add" runat="server" Text="Add Name" onclick="btn_add_Click"
            Width="100px" /><br />
    <asp:DropDownList ID="DropDownList1" runat="server">
        </asp:DropDownList><br />
        
    </div>
    </form>
</body>
</html>

using System;
using System.Collections;
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;
namespace Dropdownlist_Insertshow
{
    public partial class _Default : System.Web.UI.Page
    {
        string strConnString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
        string str;
        SqlCommand com;

        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                dropbind();
            }
        }

        protected void btn_add_Click(object sender, EventArgs e)
        {
            DropDownList1.Items.Clear();
            SqlConnection con = new SqlConnection(strConnString);
            com = new SqlCommand();
            com.Connection = con;
            com.CommandType = CommandType.Text;
            com.CommandText = "insert into employee(name)values(@name)";
            com.Parameters.Clear();
            com.Parameters.AddWithValue("@name", txt_name.Text);
            if (con.State == ConnectionState.Closed)
                con.Open();
            com.ExecuteNonQuery();
            con.Close();
            Response.Write("Records successfully inserted");
            clear();
            dropbind();
        }
        private void clear()
        {
            txt_name.Text = "";
        }
        private void dropbind()
        {
            
            SqlConnection con = new SqlConnection(strConnString);
            DropDownList1.Items.Add("Choose Name");
            con.Open();
            str = "select * from  employee";
            com = new SqlCommand(str, con);
            SqlDataReader reader = com.ExecuteReader();
            while (reader.Read())
            {
            DropDownList1.Items.Add(reader["name"].ToString());
            }
            reader.Close();
            con.Close();
            }
        
    }
}