DateTimePicker ile Veri Getirme

//Göster Butonu.
private void button4_Click(object sender, EventArgs e)
        {
            string donustur = dateTimePicker2.Value.ToString("dd - MM - yyyy");
            baglan.Open();
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = baglan;
            cmd.CommandText = "select * from tablo1 where dogumtarihi between dogumtarihi = @dt";
            cmd.CommandType = CommandType.Text;
            cmd.Parameters.AddWithValue("@dt", donustur);
            bilgi.SelectCommand = cmd;
            DataSet ds = new DataSet();
            bilgi.Fill(ds);
            dataGridView1.DataSource = ds.Tables[0];
            baglan.Close();
            kisileriListele();
        }

namespace ProjeDeneme_1
{
    public partial class Form1 : Form
    {
        SqlConnection baglan = new SqlConnection("Data Source=DESKTOP-7VA9GU2;Initial Catalog=deneme1; Integrated Security=True");
        SqlCommand komut;
        SqlDataAdapter bilgi;
        DataTable tablo = new DataTable();
        string sorgu;
        string secilen_id = "-1";
        public Form1()