Associating a ListView with a collection of objects

Question

How can you use a ListView to show the user a collection of objects, and to manage those objects?

Answer 1

For the purpose of argument, here's our design goal: We've got a "monster" object, and that "monster" will have several "powers." The user interacts with the powers via a ListView item.

First, we create a Power object. Give the object the following method:

public ListViewItem makeKey()
{
    return new ListViewItem(name);
}

where name is the name of the power, and a string. This ListViewItem will serve as a key, allowing us to identify and retrieve this power later.

Next, we need to add somewhere in the Monster object to keep track of all these powers.

public Dictionary<ListViewItem,Power> powers;

So now we need a way to add powers to the monster.

public void addPower(Power newPower) {
    ListViewItem key = newPower.makeKey();
    monster.powers.add(key, newPower);
}

Ok, almost done! Now we've got a dictionary of ListViewItems which are tied to the monster's powers. Just grab the keys from that dictionary and stick them in a ListView:

foreach (ListViewItem key in powers.Keys)
    powerList.Items.Add(key);

Where powerList is the ListView we're adding the ListViewItems to.

Alright, so we've got the ListViewItems in the ListView! Now, how do we interact with those? Make a button and then a function something like this:

private void powerRemoveButton_Click(object sender, EventArgs e)
{
    if (powerList.SelectedIndices.Count > 0)
    {
        int n = powerList.SelectedIndices[0];
        ListViewItem key = powerList.Items[n];
        monster.powers.Remove(key);
        powerList.Items.Remove(key);
    }
    else
    {
        MessageBox.Show("No power selected.");
    }
}

And that's that. I hope you've found this helpful. I'm not sure if this was an intentional aspect of their design, but ListViews and Dictionaries blend together so amazingly well when you use a ListViewItem as a key that it's a joy!