During my most recent encounter with this control of the third kind, I needed to use a ComboBox column, and that column needed to have an effect on the contents of the other controls. Normally, you could just hook up a cellvaluechanged event or something of that nature, but that doesn't work out on a ComboBox control in a DataGridView column... There's no event that would fire when a user selected an item in the dropdown. Only after the user selected the item, then refocused on some other control.
That was annoying. Too many clicks for the user! When I select the item in the dropdown, the row should react, I shouldn't have to click elsewhere.
So here's a quick example of what I did to get that working. In the example, we handle the datagridview's EditControlShowing event, then grab a reference to the combobox, then unwire any previous events we may have hooked up to SelectionChangeCommitted, then wire the event. In the SelectionChangeCommitted event we call _dataGridView.EndEdit() to effect the other rows.
Enjoy!
public class Example
{
///
/// Constructor
///
public Example()
{
_dataGridView = new DataGridView();
// setup the datagridview here.
DataGridViewComboBoxColumn fooColumn = new DataGridViewComboBoxColumn();
fooColumn.Name = "Foo";
fooColumn.ValueType = typeof(String);
fooColumn.HeaderText = "Foo";
fooColumn.Items.Add("Bar");
fooColumn.Items.Add("Baz");
fooColumn.Items.Add("Fizz");
fooColumn.Items.Add("Buzz");
fooColumn.Items.Add("FizzBuzz");
fooColumn.DefaultCellStyle.NullValue = "Bar";
_dataGridView.Columns.Add(fooColumn);
// hook up editing control showing event
_dataGridView.EditingControlShowing += new DataGridViewEditingControlShowingEventHandler(_dataGridView_EditingControlShowing);
// create a delegate for the method that will handle the event
_comboBoxSelectDelegate = new EventHandler(combo_SelectionChangeCommitted);
}
private DataGridView _dataGridView;
private EventHandler _comboBoxSelectDelegate;
void _dataGridView_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
// get the control from the event args.
ComboBox combo = e.Control as ComboBox;
if (combo != null)
{
// remove the event subscription if it exists.
combo.SelectionChangeCommitted -= comboSelectDelegate;
// add a subscription to the event
combo.SelectionChangeCommitted += comboSelectDelegate;
}
}
void combo_SelectionChangeCommitted(object sender, EventArgs e)
{
// handle the event, and end edit mode
_dataGridView.EndEdit();
}
}
