private static void Popup_Opened(object sender, EventArgs e)
{
var popup = (Popup)sender;
if (popup.TemplatedParent is MenuItem menuItem)
{
var topLine = GetTopLine(menuItem);
if (topLine == null)
{
return;
}
topLine.HorizontalAlignment = HorizontalAlignment.Left;
topLine.Width = menuItem.ActualWidth;
topLine.Margin = new Thickness();
var positionLeftTop = menuItem.PointToScreen(new Point());
var positionRightBottom = menuItem.PointToScreen(new Point(menuItem.ActualWidth, menuItem.ActualHeight));
ScreenHelper.FindMonitorRectsFromPoint(InteropMethods.GetCursorPos(), out _, out var workAreaRect);
var panel = VisualHelper.GetParent <Panel>(topLine);
if (positionLeftTop.X < 0)
{
topLine.Margin = new Thickness(positionLeftTop.X - panel.Margin.Left, 0, 0, 0);
}
else if (positionLeftTop.X + panel.ActualWidth > workAreaRect.Right)
{
var overflowWidth = positionRightBottom.X - workAreaRect.Right;
if (overflowWidth > 0)
{
topLine.Width -= overflowWidth + panel.Margin.Right;
}
topLine.HorizontalAlignment = HorizontalAlignment.Left;
topLine.Margin = new Thickness(positionLeftTop.X + panel.ActualWidth - workAreaRect.Right + panel.Margin.Right, 0, 0, 0);
}
if (positionRightBottom.Y > workAreaRect.Bottom)
{
topLine.Width = 0;
topLine.HorizontalAlignment = HorizontalAlignment.Stretch;
topLine.Margin = new Thickness();
}
}
}