我想在combobox中显示数据库中一列的值，不要重复的。可是我的以下代码做出来是全部的值
，该怎么改啊！谢谢大家了
using System;
using System.Collections.Generic;
using
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace text5
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
           
            SqlConnection con = new SqlConnection("server=127.0.0.1;uid=sa;pwd=;database=master");
            con.Open();
            SqlCommand sqlcmd = new SqlCommand("select * from spt_datatype_info_ext", con);
            SqlDataReader reader = sqlcmd.ExecuteReader();
            while (reader.Read())
            {
                cb.Items.Add(reader[1].ToString());
            }
            reader.Close();
            con.Close();
           
        }
    }
}

OK谢谢拉

OK谢谢拉

OK谢谢拉