Datagridview

 SqlConnection sqlcon = new SqlConnection("");
        SqlCommand sqlcmd = new SqlCommand();
        DataTable dt = new DataTable();
        SqlDataAdapter da = new SqlDataAdapter();
        public Form1()
        {
            InitializeComponent();
        }      
        private void button1_Click(object sender, EventArgs e)
        {
            sqlcon.Open();
            sqlcmd = new SqlCommand("select * from emp", sqlcon);
            da = new SqlDataAdapter(sqlcmd);
            dt.Clear();
            da.Fill(dt);
            if (dt.Rows.Count > 0)
            {
                string s;
                s=comboBox1.Text;
                dt.Columns.Add(comboBox1.Text);
                DataRow dr;
                dr = dt.NewRow();
                dr[s] = textBox1.Text;
                dt.Rows.Add(dr);
                dataGridView1.DataSource = dt;
            }
            sqlcon.Close();
}