CODEWITHSUNDEEP
c#.netwinformslistview
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Reputation: 513

Removing items in ListView

I've got a loop in a button action for removing empty items in my ListView, but the problem is, when I press the button it deletes successfully only the items that were single. I mean: it does not remove items, when there are few one after another:

example:

a1 = ""
a2 = "qwe"
a3 = ""
a4 = ""
a5 = "qwe"

so, after button click, the result will be:

a2 = "qwe"
a3(or a4 idk) = ""
a5 = "qwe"

I think it's easy logic problem, but I can't figure it out.

for (int i = 0; i < listView1.Items.Count; i++) 
            {
                if (listView1.Items[i].SubItems[2].Text == "")
                {
                    listView1.Items[i].Remove();
                }
            }

So the problem is that the loop skips one check after it finds the empty value. How do I fix it?

Upvotes: 6

Views: 3348

Answers (1)

Dmitrii Bychenko
Dmitrii Bychenko

Reputation: 186668

When removing items in a for loop, loop backward:

for (int i = listView1.Items.Count - 1; i >= 0; --i) 
  if (listView1.Items[i].SubItems[2].Text == "")
    listView1.Items[i].Remove();

or modify the for loop into

for (int i = 0; i < listView1.Items.Count; ) // no ++i here
  if (listView1.Items[i].SubItems[2].Text == "")
    listView1.Items[i].Remove();
  else  
    i += 1; // ...but it's here

This is a common principle beyond ListView items. See what's getting on: imagine that you want remove A from the collection

  [A, A, B, A]

when you've found that's 0th item must be deleted, you should not increment counter after deletion, but test new 0th item again.

Upvotes: 5

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