gridvew not display in duplicate values

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm2.aspx.cs" Inherits="Gridview.WebForm2" %>





   


   

   

   
   
   

   

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 Gridview
{
    public partial class WebForm2 : System.Web.UI.Page
    {
        string connStr = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
        SqlCommand com;
        SqlDataAdapter sqlda;
        DataSet ds;
        string str;

        protected void Page_Load(object sender, EventArgs e)
        {
            bindgrid();
        }
        private void bindgrid()
        {
            SqlConnection con = new SqlConnection(connStr);
            con.Open();
            str = "SELECT DISTINCT * FROM emp";
            com = new SqlCommand(str, con);
            sqlda = new SqlDataAdapter(com);
            ds = new DataSet();
            sqlda.Fill(ds, "emp");
            GridView1.DataMember = "emp";
            GridView1.DataSource = ds;
            GridView1.DataBind();
            con.Close();
        }
    }
}