Binding (and refreshing) a List to a ListBox

Question

I have two ListBoxes and I want to move items between them. The code looks like this:

    private void FillItems()
    {
        allItems = GetAllItems();
        availableItems = new List<string>(allItems);
        selectedItems = new List<string>();

        itemsListBox.DataSource = availableItems;
        selectedItemsListBox.DataSource = selectedItems;
    }

    private void addItemButton_Click(object sender, EventArgs e)
    {
        var itemsToAdd = itemsListBox.SelectedItems;
        foreach (string item in itemsToAdd)
        {
            availableItems.Remove(item);
            selectedItems.Add(item);
        }
    }

Simple enough. I move strings from one list into another.

Now this doesn't work, just as it shouldn't. I realise that it's missing some way of notifying about collection change. So I tried these options:

Calling Refresh() on the list boxes. No avail.
Using an extra layer of data binding (BindingSource). Also no avail.
Calling ResetBindings() on the control. Still nothing.

What am I doing wrong here? Should I use some kind of an observable collection?

score 2 · Accepted Answer · edited May 23 '17 at 10:32

If you import the System.ComponentModel namespace, then you can use a binding list of string, which will automatically raise events on changes:

private void FillItems()
{
    allItems = GetAllItems();
    availableItems = new BindingList<string>(allItems);
    selectedItems = new BindingList<string>();

    itemsListBox.DataSource = availableItems;
    selectedItemsListBox.DataSource = selectedItems;
}

private void addItemButton_Click(object sender, EventArgs e)
{
    object itemsToAdd = itemsListBox.SelectedItems;
    foreach (string item in itemsToAdd) {
        availableItems.Remove(item);
        selectedItems.Add(item);
    }
}

This link has further information on the difference between observable collections and binding lists. difference between ObservableCollection and BindingList

Worked. For posterity: I had to rewrite `SelectedItems` to a separate list because the collection changes, causing the `foreach` to crash. — John NoCookies, Jul 05 '13 at 11:01

score 0 · Answer 2 · answered Jul 05 '13 at 10:35

0

I prefer using ObservableCollections because you do not need to refresh binding yoursef, take a look

http://msdn.microsoft.com/en-us/library/ms668604.aspx

answered Jul 05 '13 at 10:35

Kamil Budziewski

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score 0 · Answer 3 · edited May 23 '17 at 12:05

0

You can also use BindingList

DIfference between BindingList and ObservableCollection explained here)

edited May 23 '17 at 12:05

Community

1
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answered Jul 05 '13 at 10:48

Arie

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Binding (and refreshing) a List to a ListBox

3 Answers3