Мне нужно реализовать каскадирование ComboBoxes за несколько DataGridView. В качестве доказательства концепции я собрал код ниже. 3 столбца (Клиент, Страна, Город). При выборе Страна Город должен заполнить, но это не работает.
Есть ли лучший способ добиться этого и исправить то, что я делаю неправильно?
public partial class Form1 : Form
{
private List<Customer> customers;
private List<Country> countries;
private List<City> cities;
private ComboBox cboCountry;
private ComboBox cboCity;
public Form1()
{
InitializeComponent();
countries = GetCountries();
customers = GetCustomers();
SetupDataGridView();
}
private List<Customer> GetCustomers()
{
var customerList = new List<Customer>
{
new Customer {Id=1,Name = "Jo",Surname = "Smith"},
new Customer {Id=2,Name = "Mary",Surname = "Glog"},
new Customer {Id=3,Name = "Mark",Surname = "Bloggs"}
};
return customerList;
}
private List<Country> GetCountries()
{
var countryList = new List<Country>
{
new Country {Id=1,Name = "England"},
new Country {Id=2,Name = "Spain"},
new Country {Id=3,Name = "Germany"}
};
return countryList;
}
private List<City> GetCities(string countryName)
{
var cityList = new List<City>();
if (countryName == "England") cityList.Add(new City { Id = 1, Name = "London" });
if (countryName == "Spain") cityList.Add(new City { Id = 2, Name = "Madrid" });
if (countryName == "Germany") cityList.Add(new City { Id = 3, Name = "Berlin" });
return cityList;
}
private void SetupDataGridView()
{
dataGridView1.CellLeave += dataGridView1_CellLeave;
dataGridView1.EditingControlShowing += dataGridView1_EditingControlShowing;
DataGridViewTextBoxColumn colCustomer = new DataGridViewTextBoxColumn();
colCustomer.Name = "colCustomer";
colCustomer.HeaderText = "CustomerName";
DataGridViewComboBoxColumn colCountry = new DataGridViewComboBoxColumn();
colCountry.Name = "colCountry";
colCountry.HeaderText = "Country";
DataGridViewComboBoxColumn colCity = new DataGridViewComboBoxColumn();
colCity.Name = "colCity";
colCity.HeaderText = "City";
dataGridView1.Columns.Add(colCustomer);
dataGridView1.Columns.Add(colCountry);
dataGridView1.Columns.Add(colCity);
//Databind gridview columns
((DataGridViewComboBoxColumn)dataGridView1.Columns["colCountry"]).DisplayMember = "Name";
((DataGridViewComboBoxColumn)dataGridView1.Columns["colCountry"]).ValueMember = "Id";
((DataGridViewComboBoxColumn)dataGridView1.Columns["colCountry"]).DataSource = countries;
((DataGridViewComboBoxColumn)dataGridView1.Columns["colCity"]).DisplayMember = "Name";
((DataGridViewComboBoxColumn)dataGridView1.Columns["colCity"]).ValueMember = "Id";
((DataGridViewComboBoxColumn)dataGridView1.Columns["colCity"]).DataSource = cities;
foreach (Customer cust in customers)
{
dataGridView1.Rows.Add(cust.Name + " " + cust.Surname);
}
}
private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
//register a event to filter displaying value of items column.
if (dataGridView1.CurrentRow != null && dataGridView1.CurrentCell.ColumnIndex == 2)
{
cboCity = e.Control as ComboBox;
if (cboCity != null)
{
cboCity.DropDown += cboCity_DropDown;
}
}
//Register SelectedValueChanged event and reset item comboBox to default if category changes
if (dataGridView1.CurrentRow != null && dataGridView1.CurrentCell.ColumnIndex == 1)
{
cboCountry = e.Control as ComboBox;
if (cboCountry != null)
{
cboCountry.SelectedValueChanged += cboCountry_SelectedValueChanged;
}
}
}
void cboCountry_SelectedValueChanged(object sender, EventArgs e)
{
//If category value changed then reset item to default.
dataGridView1.CurrentRow.Cells[2].Value = 0;
}
void cboCity_DropDown(object sender, EventArgs e)
{
string countryName = dataGridView1.CurrentRow.Cells[1].Value.ToString();
List<City> cities = new List<City>();
cities = GetCities(countryName);
cboCity.DataSource = cities;
cboCity.DisplayMember = "Name";
cboCity.ValueMember = "Id";
}
private void dataGridView1_CellLeave(object sender, DataGridViewCellEventArgs e)
{
if (cboCity != null) cboCity.DropDown -= cboCity_DropDown;
if (cboCountry != null)
{
cboCountry.SelectedValueChanged -= cboCountry_SelectedValueChanged;
}
}
}
public class Country
{
public int Id { get; set; }
public string Name { get; set; }
}
public class City
{
public int Id { get; set; }
public string Name { get; set; }
}
public class Customer
{
public int Id { get; set; }
public string Name { get; set; }
public string Surname { get; set; }
}
}
