Casting an Item Collection from a listbox to a generic list

Question

I want to find a better way of populating a generic list from a checkedlistbox in c#.

I can do the following easily enough:

List selec         


        

Answer 1

This is not exactly the answer to your requirement, but posting a more general answer. You could do it in a variety of ways:

1)

T[] items = new T[lb.Items.Count];
lb.Items.CopyTo(items, 0);
var lst = new List(items);

2) looping and adding using foreach as you mentioned.

3) using Linq

var lst = lb.Items.Cast().ToList();

4) or

var lst = lb.Items.OfType().ToList();

When I did some performance testing like below, I found copying to array method the fastest while the Linq methods slower. Of course in real world scenarios these wouldnt matter. I prefer the 3rd method (Linq) for readability.

DateTime d = DateTime.Now;
for (int i = 0; i < 10000; i++)
{
    Action();
}
MessageBox.Show((DateTime.Now - d).TotalMilliseconds.ToString());

For an iteration of 10000 times run multiple times with about 300 items in list box,

1) ~100ms

2) ~150ms

3) ~250ms

4) ~260ms