private void DocumentView_OnMouseDown(object sender, MouseButtonEventArgs e)
{
if (Keyboard.IsKeyDown(Key.LeftAlt))
{
return;
}
DocumentViewModel viewModel = DataContext as DocumentViewModel;
FrameworkElement sourceControl = e.OriginalSource as FrameworkElement;
if (sourceControl != null)
{
viewModel?.DeselectAll();
SelectNearLine(e);
if (e.ChangedButton == MouseButton.Left)
{
IContentSelectable selectableContent = sourceControl.DataContext as IContentSelectable;
if (selectableContent?.CanSelect == true)
{
_isDragging = true;
viewModel?.StartSelection(e.GetPosition(CanvasItemContainer));
}
}
}
}