在UWP中单击并拖动选择框

private bool isSelecting = false;
private Point startPoint;

private void OnMouseDown(object sender, MouseButtonEventArgs e)
{
    if (e.LeftButton == MouseButtonState.Pressed)
    {
        startPoint = e.GetPosition(this);
        isSelecting = true;
    }
}

private void OnMouseMove(object sender, MouseEventArgs e)
{
    if (isSelecting && e.LeftButton == MouseButtonState.Pressed)
    {
        Point currentPoint = e.GetPosition(this);
        double left = Math.Min(startPoint.X, currentPoint.X);
        double top = Math.Min(startPoint.Y, currentPoint.Y);
        double width = Math.Abs(currentPoint.X - startPoint.X);
        double height = Math.Abs(currentPoint.Y - startPoint.Y);

        // 更新选择框的位置和大小
        Canvas.SetLeft(selectionBox, left);
        Canvas.SetTop(selectionBox, top);
        selectionBox.Width = width;
        selectionBox.Height = height;
    }
}

private void OnMouseUp(object sender, MouseButtonEventArgs e)
{
    if (isSelecting)
    {
        isSelecting = false;

        // 根据选择框的位置和大小，确定选中的项目或元素
        Rect selectionRect = new Rect(Canvas.GetLeft(selectionBox), Canvas.GetTop(selectionBox), selectionBox.Width, selectionBox.Height);
        List<UIElement> selectedItems = new List<UIElement>();

        foreach (UIElement item in itemsContainer.Children)
        {
            Rect itemRect = new Rect(Canvas.GetLeft(item), Canvas.GetTop(item), item.ActualWidth, item.ActualHeight);

            if (selectionRect.IntersectsWith(itemRect))
            {
                selectedItems.Add(item);
            }
        }

        // 对选中的项目或元素进行处理
        // ...

        // 清除选择框
        Canvas.SetLeft(selectionBox, 0);
        Canvas.SetTop(selectionBox, 0);
        selectionBox.Width = 0;
        selectionBox.Height = 0;
    }
}