CODEWITHSUNDEEP
c#wpfxamldrag-and-droplistbox
Dbloom
Dbloom

Reputation: 1402

WPF - DragOver event is not firing on my Listbox

I am trying to implement drag and drop functionality in my WPF application. I have a Listbox that I would like to be able to drop files on from Windows Explorer. These files would then be added to the listbox. I had this working at one time, following this tutorial: Drag and drop files to WPF application and asynchronously upload to ASP.NET Web API. Minus the upload to web api part. I just want to show the files in my listbox.

The problem is that the DragOver event never fires. What am I missing? I had this working earlier, but some small tweak messed it up.

Here is my XAML (simplified the parent elements):

<Window>
  <Grid>
    <TabControl>
      <TabItem>
        <Grid>
          <GroupBox>
            <ListBox Name="lstTarget" AllowDrop="True"
                     Drop="lstTarget_Drop"
                     DragOver="lstTarget_DragOver"
                     DragLeave="lstTarget_DragLeave"
                     BorderThickness="3"
                     BorderBrush="Red"
                     >
            </ListBox>

Here is my code behind

private void lstTarget_Drop(object sender, DragEventArgs e)
{
    if (e.Data.GetDataPresent(DataFormats.FileDrop))
    {
        string[] files = (string[])e.Data.GetData(DataFormats.FileDrop);
        foreach (string filePath in files)
        {
            lstTarget.Items.Add(filePath);
        }
    }

    var listbox = sender as ListBox;
    listbox.Background = new SolidColorBrush(Color.FromRgb(226, 226, 226));
}
private void lstTarget_DragOver(object sender, DragEventArgs e)
{
    lstTarget.BorderBrush = Brushes.Green;

    if (e.Data.GetDataPresent(DataFormats.FileDrop))
    {
        e.Effects = DragDropEffects.Copy;
        var listbox = sender as ListBox;
        listbox.Background = new SolidColorBrush(Color.FromRgb(155, 155, 155)           
    }
    else
    {
        e.Effects = DragDropEffects.None;
    }
}

private void lstTarget_DragLeave(object sender, DragEventArgs e)
{
    var listbox = sender as ListBox;
    listbox.Background = new SolidColorBrush(Color.FromRgb(226, 226, 226));
}

Upvotes: 2

Views: 2581

Answers (2)

rpaulin56
rpaulin56

Reputation: 476

I am not sure the problem is that, but I would rather use DragEnter instead of DragOver, as you need to check the dragged data content just once

Upvotes: 1

Dbloom
Dbloom

Reputation: 1402

Well I'm a dummy. If I run my app as Administrator, then I can't drag in items from Explorer. Most likely they are running in a different security context.

There was nothing wrong with my code.

Upvotes: 9

Related Questions