"No value given for one or more required parameters" error when working with tabcontrol

Hello,

I have a form with tabcontrol. I want depending on the value in the textBox in the form, to fill the datagridview in the tabcontrol. I wrote this code and got the error:"No value given for one or more required parameters"

 private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
  {
 
  if (e.KeyChar == (char)13)
  {
  dateTimePicker2.Focus(); 
  OleDbCommand command3 = new OleDbCommand();
  command3.Connection = conn;
 
  command3.CommandText = "SELECT * from Avt where Brdog=?";
  command3.Parameters.AddWithValue("@Brgod", textBox1.Text);
  
  
  conn.Open();
  DataSet1 _dataset = new DataSet1();
  OleDbDataAdapter oleDbAdapter1 = new OleDbDataAdapter(new OleDbCommand(command3.CommandText, conn));
 
  command3.ExecuteNonQuery();
  _dataset.Clear();
  oleDbAdapter1.Fill(_dataset, "Avt");
  dataGridView1.DataSource = _dataset.Tables["Avt"].DefaultView;
 
  conn.Close();
 
  }
  }
But I don't have an idea why I get this error when I give the parameter value in the bold sentence.
Can anybody help me please what could be the problem? Thanks