C# removing items from listbox

Question

I have a listbox being populated from a SQLDATA pull, and it pulls down some columns that i dont want like OBJECT_dfj, OBJECT_daskd. The key is all of these being with OBJE

Answer 1

You want to iterate backwards through using a counter instead of foreach. If you iterate forwards you have to adjust the counter as you delete items.

for(int i=listBox1.Items.Count - 1; i > -1; i--) {
{
    if(listBox1.Items[i].Contains("OBJECT"))
    {
        listBox1.Items.RemoveAt(i);
    }
}

Answer 2

You can try this also, if you don't want to deal with the enumerator:

object ItemToDelete = null;
foreach (object lsbItem in listbox1.Items)
{
   if (lsbItem.ToString() == "-ITEM-")
   {
      ItemToDelete = lsbItem;                                  
   }
}

if (ItemToDelete != null)
    listbox1.Items.Remove(ItemToDelete);

Answer 3

I found out the hard way that if your listbox items are assigned via a data source

List<String> workTables = hhsdbutils.GetWorkTableNames();
listBoxWork.DataSource = workTables;

...you have to unbind that before doing the removal:

listBoxWork.DataSource = null;
for (int i = listBoxWork.Items.Count - 1; i >= 0; --i)
{
    if (listBoxWork.Items[i].ToString().Contains(listboxVal))
    {
        listBoxWork.Items.RemoveAt(i);
    }
}

Without the "listBoxWork.DataSource = null;" line, I was getting, "Value does not fall within the expected range"

Answer 4

The problem here is that you're changing your enumerator as you remove items from the list. This isn't valid with a 'foreach' loop. But just about any other type of loop will be OK.

So you could try something like this:

for(int i=0; i < listBox1.Items.Count; )
{
    string removelistitem = "OBJECT";
    if(listBox1.Items[i].Contains(removelistitem))
         listBox1.Items.Remove(item);
    else
        ++i;
}