CODEWITHSUNDEEP
c#.netwinformslistview
Pete Michaud
Pete Michaud

Reputation: 1833

C# Drag & Drop Between ListViews

I'm trying to create a self-contained Winforms control called DragDropListView. It derives from ListView.

I have code that allows the user to sort list items within the control by dragging and dropping the items in the new location. I achieved that by overriding OnDragDrop, OnDragOver, OnDragEnter, OnItemDrag.

The issue I have is with dragging from one listview to a completely different listview. The event fires on the other list view as expected, but the method doesn't take a "sender" argument, so there's no good way to tell where the items are being dragged from, and no way I can figure out to actually grab the items being dragged. The current code works with stuff like "this.SelectedItems," but I'd like it to be "sender.SelectedItems".

I guess the reason there is no sender argument is that the control isn't supposed to responsible for knowing that much about its environment, and the host Form should handle the interaction between two controls, but I'm trying to build self contained controls that have this functionality, so letting it bleed onto the form isn't going to work.

Ideas?

Upvotes: 1

Views: 3692

Answers (1)

Homam
Homam

Reputation: 23871

I think you can know the ListView from the Items by listViewItem.ListView property, Check it.

I didn't test the code:

private void listView1_DragEnter(object sender, DragEventArgs e)
{
    if (!e.Data.GetDataPresent(typeof(ListView.ListViewItemCollection)))
    {
        e.Effect = DragDropEffects.None;
        return;
    }

    var items = (ListView.ListViewItemCollection)e.Data.GetData(typeof(ListView.ListViewItemCollection));

    if (items.Count > 0 && items[0].ListView != listView1)
    {
        e.Effect = DragDropEffects.None;
        return;
    }
}

Check DragEventArgs , this sample in CodeProject [VB.Net] Good luck!

Upvotes: 1

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