Reason why IDataObject.GetData from System.Windows.Forms returning empty string[] on a drag and drop event

I'm trying to make it so users can add their own textures to a program I'm making and I'm doing it but creating a Windows Form that'll receive a drag and drop event and send that data back in. Here's a stripped down version of the code.

using System.Windows.Forms; public class DragAndDrop : MonoBehaviour { Form DropForm; void Start() { }

 public void ShowDropDialog()
 {
     print("starting window");
     DropForm = new DragDropForm();
     DropForm.ShowDialog();
 }

 class DragDropForm : Form
 {
     public DragDropForm()
     {
         this.AllowDrop = true;
         this.Width = 300;
         this.Height = 300;
         this.Text = "Drag Images here";
         this.DragDrop += new DragEventHandler(this.DragDropForm_DragDrop);
         this.DragEnter += new DragEventHandler(this.DragDropForm_DragEnter);
     }

     void DragDropForm_DragEnter(object sender, DragEventArgs e)
     {
         if (e.Data.GetDataPresent(DataFormats.FileDrop))
         {
             e.Effect = DragDropEffects.Link;
             this.BackColor = System.Drawing.Color.Blue;
         }
         string[] files = (string[])e.Data.GetData(DataFormats.FileDrop);
         foreach (string file in files)
         {
         }
     }
     void DragDropForm_DragDrop(object sender, DragEventArgs e)
     {
         print("dropped");
         object data = e.Data.GetData(DataFormats.FileDrop);
         this.BackColor = System.Drawing.Color.Green;
         string[] files = (string[])e.Data.GetData(DataFormats.FileDrop);
         foreach (string file in files)
         {
         }
         print("closing");
         this.Close();
     }
 }

}

The problems are the Drop event doesn't fire at all, hovering with a dragged file gives the crossed out circle like it doesn't let me drop it, and the e.Data.GetData only returns an empty string instead of a filepath. It really frustrating as I have no idea if I'm doing something wrong.