How do you refresh a combo box item in-place?

Question

The ComboBox Items collection is an ObjectCollection, so of course you can store anything you want in there, but that means you don't get a Text property like you would with, say, a ListViewItem. The ComboBox displays the items by calling ToString() on each item, or using reflection if the DisplayMember property is set.

My ComboBox is in DropDownList mode. I have a situation where I want to refresh the item text of a single item in the list when it gets selected by the user. The problem is that the ComboBox doesn't re-query for the text at any time besides when it loads up, and I can't figure out how else to do what I want besides removing and re-adding the selected item like so:

PlantComboBoxItem selectedItem = cboPlants.SelectedItem as PlantComboBoxItem;

// ...

cboPlants.BeginUpdate();

int selectedIndex = cboPlants.SelectedIndex;
cboPlants.Items.RemoveAt(selectedIndex);
cboPlants.Items.Insert(selectedIndex, selectedItem);
cboPlants.SelectedIndex = selectedIndex;

cboPlants.EndUpdate();

This code works fine, except for the fact that my SelectedIndex event ends up getting fired twice (once on the original user event, and then again when I re-set the property in this code). In this case, it's not a big deal that the event is fired twice, but it's inefficient, and I hate that. I could rig up a flag so it exits the event the second time, but that's hacking.

Is there a better way to get this to work?

Answer 1

A dirty hack:

typeof(ComboBox).InvokeMember("RefreshItems", BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.InvokeMethod, null, cboPlants, new object[] { });