How to store the content of an InkCanvas in a List

Question

I'm implementing an undo/redo feature to an InkCanvas , so I need to save the content of the InkCanvas in a list (not a file) every time it gets modified. I'm currently saving it in an InMemoryRandomAccessStream but since it needs to be an instance I can't use it in a list. Is there a way I could store more than one content and retrieve when necessary?

Answer 1

According to your requirement of undo/redo feature, you can use AddStroke and DeleteSelected method to add or delete the stroke that you want to undo or redo. Here is my code, you can have a reference.

private List<InkStroke> undoList = new List<InkStroke>();
private void Undo(object sender, RoutedEventArgs e)
{
    IReadOnlyList<InkStroke> inkList = inkCanvas.InkPresenter.StrokeContainer.GetStrokes();
    if (inkList.Count > 0)
    {
        InkStroke undoStroke = inkList[inkList.Count - 1];
        undoStroke.Selected = true;
        undoList.Add(undoStroke.Clone());
        inkCanvas.InkPresenter.StrokeContainer.DeleteSelected();
    }
}

private void Redo(object sender, RoutedEventArgs e)
{
    if (undoList.Count > 0)
    {
        InkStroke redoStroke = undoList[undoList.Count - 1];
        inkCanvas.InkPresenter.StrokeContainer.AddStroke(redoStroke);
        undoList.Remove(redoStroke);
    }
}