C# Drag&Drop Move of Items in Current ListView

Question

1) How do you move items in a ListView using Drag&Drop? I have implemented D&D copy for files dragged from a directory.

2) BTW, how do you get a directory link by D&D to ListView, I've seen applications that get the directory path by D&D from address bar of Windows Explorer.

private void lvwFiles_DragEnter(object sender, DragEventArgs e)
{
    if (e.Data.GetDataPresent(DataFormats.FileDrop))
        e.Effect = DragDropEffects.Copy;
    else
        e.Effect = DragDropEffects.None;
}

private void lvwFiles_DragDrop(object sender, DragEventArgs e)
{
    if (e.Data.GetDataPresent(DataFormats.FileDrop))
    {
        var paths = (string[])e.Data.GetData(DataFormats.FileDrop);
        var path = Path.GetDirectoryName(paths[0]);
        paths = Media.FilterPaths(paths);
        lvwFilesAdd(path, paths);
        lvwFilesWrite();
    }
}

---

Found this @ Microsoft (VS2005; http://support.microsoft.com/kb/822483), I'm trying to make sense of this code and make it work in my program. I'll see how to separate this from the code already in the DragEnter & DragDrop event handlers.

//lvwFiles_ItemDrag event handler
//
//Begins a drag-and-drop operation in the ListView control.
lvwFiles.DoDragDrop(lvwFiles.SelectedItems, DragDropEffects.Move);

//lvwFiles_DragEnter event handler
//
int len=e.Data.GetFormats().Length-1 ;
int i;
for (i = 0 ; i<=len ;i++)
{
    if (e.Data.GetFormats()[i].Equals("System.Windows.Forms.ListView+SelectedListViewItemCollection"))
    {
        //The data from the drag source is moved to the target. 
        e.Effect = DragDropEffects.Move;
    }
}

//lvwFiles_DragDrop event handler
//
//Return if the items are not selected in the ListView control.
if(lvwFiles.SelectedItems.Count==0)
{
   return;
}
//Returns the location of the mouse pointer in the ListView control.
Point cp = lvwFiles.PointToClient(new Point(e.X, e.Y));
//Obtain the item that is located at the specified location of the mouse pointer.
ListViewItem dragToItem = lvwFiles.GetItemAt(cp.X, cp.Y);
if(dragToItem==null)
{
    return;
} 
//Obtain the index of the item at the mouse pointer.
int dragIndex = dragToItem.Index;
ListViewItem[] sel=new ListViewItem [lvwFiles.SelectedItems.Count];
for(int i=0; i<=lvwFiles.SelectedItems.Count-1;i++)
{
    sel[i]=lvwFiles.SelectedItems[i];
}
for(int i=0; i<sel.GetLength(0);i++)
{ 
    //Obtain the ListViewItem to be dragged to the target location.
    ListViewItem dragItem = sel[i];
    int itemIndex = dragIndex;
    if(itemIndex==dragItem.Index)
    {
        return;
    }
    if(dragItem.Index<itemIndex)
        itemIndex++;
    else
        itemIndex=dragIndex+i;
   //Insert the item at the mouse pointer.
   ListViewItem insertItem = (ListViewItem)dragItem.Clone();
   lvwFiles.Items.Insert(itemIndex, insertItem);
   //Removes the item from the initial location while 
   //the item is moved to the new location.
   lvwFiles.Items.Remove(dragItem);
}

Answer 1

Have a look at ObjectListView -- an open source wrapper around a .NET WinForms ListView.

It supports rearranging list view items by dragging, plus a whole lot more. See Taking the drag out of Drag and Drop