private async void Grid_Drop(object sender, DragEventArgs e)
{
DragLeave.Begin();
if (e.DataView.Contains(StandardDataFormats.StorageItems))
{
AddAttachement((await e.DataView.GetStorageItemsAsync()).First() as StorageFile);
}
}
private void rectangle_DragLeave(object sender, DragEventArgs e)
{
DragLeave.Begin();
}