2組合框在datagridview的

Question

我與在windowsforms 在DataGridView的組合框delaeaing假設我有一個datagridview的2個combboxes所以我的問題是
如何根據本datagridview的從另一個comboboxcolum選擇的值填充在datagridview的comboboxcolumn

Answer 1

嗯，我想我遲到了，但你應該做的是將價值改變的事件處理程序附加到你的列。處理程序應該在您選擇新值時觸發，然後使用傳遞給該函數的參數來確定哪一行被更改，並更改該行中的第二個組合框。我會舉一個例子，但我幾乎肯定你不會回過頭來看看這個答案。

編輯： 沒想到你真的會爲此而復出，但這裏有一種方法來實現動態ComboBoxes。我不能說我完全爲這個答案感到自豪，因爲它不適用於數據綁定（你將不得不自己添加每一行並設置適當的初始值），但至少這個解決方案可以指導你朝着正確的方向或者一個新的。

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; } 
}