private void OnComboBoxInput_TextChanged(object sender, EventArgs e) { var input = _comboBoxInput.Text.Trim(); var cities = _citiesService.GetCitiesStartsWith(input); if (cities.Count > 0) { _comboBoxInput.DataSource = cities; _comboBoxInput.DisplayMember = nameof(City.Name); var sText = _comboBoxInput.Items[0].ToString(); _comboBoxInput.SelectionStart = input.Length; _comboBoxInput.SelectionLength = sText.Length - input.Length; _comboBoxInput.DroppedDown = true; } else { _comboBoxInput.DroppedDown = false; _comboBoxInput.SelectionStart = input.Length; } }