Detect Drag'n'Drop file in WPF?

Question

Is it possible to have a WPF window/element detect the drag'n'dropping of a file from windows explorer in C# .Net 3.5? I've found solutions for WinForms, but none for WPF.

Heterologous

Answer 1

Unfortunately, TextBox, RichTextBox, and FlowDocument viewers always mark drag-and-drop events as handled, which prevents them from bubbling up to your handlers. You can restore drag-and-drop events being intercepted by these controls by force-handling the drag-and-drop events (use UIElement.AddHandler and set handledEventsToo to true) and setting e.Handled to false in your handler.

Tavel

Cheers! Your idea is also discussed here: social.msdn.microsoft.com/forums/en-US/wpf/thread/… – Heterologous

Answer 2

Try the following :

    private void MessageTextBox_Drop(object sender, DragEventArgs e)
    {
        if (e.Data is DataObject && ((DataObject)e.Data).ContainsFileDropList())
        {
            foreach (string filePath in ((DataObject)e.Data).GetFileDropList())
            {
                // Processing here     
            }
        }
    }


    private void MessageTextBox_PreviewDragEnter(object sender, DragEventArgs e)
    {
        var dropPossible = e.Data != null && ((DataObject)e.Data).ContainsFileDropList();
        if (dropPossible)
        {
            e.Effects = DragDropEffects.Copy;
        }
    }

    private void MessageTextBox_PreviewDragOver(object sender, DragEventArgs e)
    {
        e.Handled = true;
    }

Rollo

Answer 3

Turns out I couldn't drop onto my TextBox for some reason, but dropping onto buttons works fine. Got it working by adding 'AllowDrop="True"' to my window and adding drop event handler to button consisting of:

private void btnFindType_Drop(object sender, DragEventArgs e)
{
  if (e.Data is System.Windows.DataObject &&
    ((System.Windows.DataObject)e.Data).ContainsFileDropList())
  {
    foreach (string filePath in ((System.Windows.DataObject)e.Data).GetFileDropList())
    {
      // Processing here
    }
  }            
}

Heterologous

Answer 4

I had similar Issue, The drop events and drag enter events were not fired. The issue was with the windows User Account Settings. Set it to least secure setting and try the same code it works.

Grassland