ListView moving items

Question

Hi, I have another problem with ListView :( Now I need to move items in group (up, down, to the beginning, to the end), but ListView is displaying moved items always at the end.

Here is sample code for moving item to the beginning:

   if (1 == listView1.SelectedItems.Count)
    {

        ListViewItem item = listView1.SelectedItems[0];
        ListViewGroup gp = item.Group;

        int index;
        index = item.Index;

        if (index < listView1.Items.Count)
        {

            index = 0;

            listView1.Items.Remove(item);

            item.Group = gp;

            listView1.Items.Insert(index, item);
        }
    }

I tried google to find some solution, and I found someone else (http://social.msdn.microsoft.com/Forums/en-US/winforms/thread/838f90cd-33d8-4c81-9ed9-85220b511afe) who had same problem like me, but his solution is not working :(

I considered using ObjectListView but I have modified ListView witch now supports drag & drop with WinAmp effect, onScroll events, scrolling synchronization etc.. and I don't want to lose this stuff :(

Answer 1

My automatic response to this question would be to check and see if it works if you say

listView1.Items.Count - 1

because the list is zero-indexed so the count is 1 greater than the last index)

Answer 2

Looking at the code, it has a few problems which make me curious. It looks like what may be the problem is the intial if statement. If there is only 1 item in the itemlist, then removing it and re-adding it will not do anything regardless of where you stick it. I believe you want <=

Also, you're setting the index to 0 right after getting it from the item you're interested in. If the code is supposed to move it to the top, Index=0 should be moved inside the if statement.

Not sure if those will solve the problem though...

Answer 3

Try this:

/// <summary>
/// Move the given item to the given index in the given group
/// </summary>
/// <remarks>The item and group must belong to the same ListView</remarks>
public void MoveToGroup(ListViewItem lvi, ListViewGroup group, int indexInGroup) {
    group.ListView.BeginUpdate();
    ListViewItem[] items = new ListViewItem[group.Items.Count + 1];
    group.Items.CopyTo(items, 0);
    Array.Copy(items, indexInGroup, items, indexInGroup + 1, group.Items.Count - indexInGroup);
    items[indexInGroup] = lvi;
    for (int i = 0; i < items.Length; i++)
        items[i].Group = null;
    for (int i = 0; i < items.Length; i++) 
        group.Items.Add(items[i]);
    group.ListView.EndUpdate();
}