private void InnerChatContainer_DragEnter(object sender, DragEventArgs e) { if (e.Data.GetDataPresent(DataFormats.FileDrop)) { string[] files = e.Data.GetData(DataFormats.FileDrop) as string[]; bool supported = true; foreach (string file in files) { if (!SupportedExtensions.Contains(Path.GetExtension(file))) { supported = false; break; } } if (supported) { e.Effect = DragDropEffects.Copy; UploadDropHere.BackColor = Color.FromArgb(200, 0, 100, 0); UploadDropHere.Text = "DROP FILES HERE"; } else { UploadDropHere.BackColor = Color.FromArgb(200, 100, 0, 0); UploadDropHere.Text = "UNSUPPORTED FILE TYPE"; } } else { e.Effect = DragDropEffects.None; UploadDropHere.BackColor = Color.FromArgb(200, 100, 0, 0); UploadDropHere.Text = "UNSUPPORTED FILE TYPE"; } UploadDropHere.Show(); UploadDropHere.BringToFront(); }