Question

我正在使用windowsforms中的datagridview中的组合框进行处理假设我在一个datagridview中有两个combbox，所以我的问题是
如何根据此数据网格视图中另一个组合框的选定值在数据网格视图中填充组合框

Answer 1

嗯，我想我有点迟到，但你应该做的是将值更改事件处理程序附加到列。处理程序应在选择新值时触发，然后使用传递给函数的参数来确定更改了哪一行并更改了行中的第二个组合框。我举了一个例子，但我几乎肯定你不会回来看看这个答案。

编辑：不认为你真的会为此回归，但这是实现动态ComboBoxes的一种方法。我不能说我对这个答案感到非常自豪，因为它不能用于数据绑定（你必须自己添加每一行并设置正确的初始值。）但至少这个解决方案可以指向正确的方向或者新的。

public partial class DualComboBoxGridViewForm : Form
{
    private Dictionary<Country, List<City>> locations;

    public DualComboBoxGridViewForm()
    {
        InitializeComponent();
        InitializeLocations();

        dataGridView1.Rows.Add(new DataGridViewRow());
    }

    private void InitializeLocations()
    {
        // Loading these from a database would be highly recommended, I 
        // just did it like this with a dictionary to it would be easier 
        // to show.
        locations = new Dictionary<Country, List<City>>();

        List<City> americanCities = new List<City>();
        americanCities.Add(new City { ID = 0, Name = "Please Select A City" });
        americanCities.Add(new City { ID = 1, Name = "Boston" });
        americanCities.Add(new City { ID = 2, Name = "New York" });

        List<City> japaneseCities = new List<City>();
        japaneseCities.Add(new City { ID = 0, Name = "Please Select A City" });
        japaneseCities.Add(new City { ID = 1, Name = "Tokyo" });
        japaneseCities.Add(new City { ID = 2, Name = "Kyoto" });

        locations.Add(new Country { ID = 0, Name = "Please Select A Country" }, new List<City>());
        locations.Add(new Country { ID = 1, Name = "USA" }, americanCities);
        locations.Add(new Country { ID = 2, Name = "Japan" }, japaneseCities);
    }

    private void InitializeDataGridView()
    {
        dataGridView1.AutoGenerateColumns = false;
        dataGridView1.EditingControlShowing += dataGridView1_EditingControlShowing;

        // Create columns
        DataGridViewTextBoxColumn eventNameColumn = new DataGridViewTextBoxColumn();
        eventNameColumn.HeaderText = "Event";

        DataGridViewComboBoxColumn countryComboBox = new DataGridViewComboBoxColumn();
        countryComboBox.Name = "Country";
        countryComboBox.HeaderText = "Country";
        countryComboBox.ValueMember = "ID";
        countryComboBox.DisplayMember = "Name";
        foreach (Country country in locations.Keys)
        {
            countryComboBox.Items.Add(country);
        }

        DataGridViewComboBoxColumn cityComboBox = new DataGridViewComboBoxColumn();
        cityComboBox.Name = "City";
        cityComboBox.HeaderText = "City";
        cityComboBox.ValueMember = "ID";
        cityComboBox.DisplayMember = "Name";

        dataGridView1.Columns.Add(eventNameColumn);
        dataGridView1.Columns.Add(countryComboBox);
        dataGridView1.Columns.Add(cityComboBox);
    }

    // Triggers when a column enters edit mode (new value not yet assigned).
    private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs args)
    {
        // we only want to change the city box if a country value is changed
        if (dataGridView1.CurrentCell.ColumnIndex == dataGridView1.Columns["Country"].Index)
        {
            ComboBox countryBox = args.Control as ComboBox;
            countryBox.SelectedIndexChanged += countryComboBox_SelectedIndexChanged;
        }
    }

    private void countryComboBox_SelectedIndexChanged(object sender, EventArgs args)
    {
        ComboBox box = sender as ComboBox;

        DataGridViewComboBoxCell cityCell = dataGridView1.Rows[dataGridView1.CurrentCell.RowIndex].Cells[dataGridView1.Columns["City"].Index] as
            DataGridViewComboBoxCell;
        cityCell.Items.Clear();
        foreach (City city in locations[box.SelectedItem as Country])
        {
            cityCell.Items.Add(city);
        }

        if (cityCell.Items.Count > 0)
        {
            cityCell.Value = cityCell.Items[0];
        }

        // Remove event handler to prevent memory leak
        box.SelectedIndexChanged -= countryComboBox_SelectedIndexChanged;
    }
}

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; }
}

datagridview中的两个组合框

1 个答案: