3rdpartylibs/fastreports.wpf/FastReport.Forms.WPF/Controls/ToolStripDropDown.PopupWrapper.cs

using System.Windows.Controls.Primitives;
using System.Windows.Media.Effects;

namespace System.Windows.Forms
{

    public partial class ToolStripDropDown
    {
        private class PopupWrapper : IPopupWrapper
        {
            private System.Windows.Controls.StackPanel panel;
            private System.Windows.Controls.Primitives.Popup popup;
            private System.Windows.Controls.Border border;

            public bool IsOpen
            {
                get => popup.IsOpen;
                set => popup.IsOpen = value;
            }
            public PlacementMode Placement { get => popup.Placement; set => popup.Placement = value; }
            public UIElement PlacementTarget { get => popup.PlacementTarget; set => popup.PlacementTarget = value; }
            public double HorizontalOffset { get => popup.HorizontalOffset; set => popup.HorizontalOffset = value; }
            public double VerticalOffset { get => popup.VerticalOffset; set => popup.VerticalOffset = value; }

            public event EventHandler Opened;
            public event EventHandler Closed;

            public void AddChild(Control child) => panel.Children.Add(child.control);
            public void RemoveChild(Control child) => panel.Children.Remove(child.control);
            public void SetChildIndex(Control child, int index) => panel.Children.Insert(index, child.control);
            public void ApplyStyle(ToolStripProfessionalRenderer r) { }

            public void FixupDpi()
            {
                if (popup.PlacementTarget != null)
                {
                    double sc1 = Helper.GetDpiScale(panel);
                    double sc2 = Helper.GetDpiScale(popup.PlacementTarget);
                    if (Math.Abs(sc1 - sc2) > 0.01)
                    {
                        // dpi is different, refresh the control
                        popup.IsOpen = true;
                        popup.IsOpen = false;
                    }
                }
            }

            public PopupWrapper(Control owner)
            {
                // it will contain children
                panel = new();

                popup = new();
                popup.UseLayoutRounding = true;
                popup.StaysOpen = false;
                popup.AllowsTransparency = true;
                popup.PopupAnimation = PopupAnimation.Slide;
                popup.Tag = owner;

                border = new()
                {
                    Margin = new Thickness(0, 0, 3, 3),
                    BorderBrush = System.Windows.SystemColors.ActiveBorderBrush,
                    BorderThickness = new Thickness(1),
                    Background = System.Windows.SystemColors.WindowBrush
                };
                border.Effect = new DropShadowEffect()
                {
                    Color = System.Windows.Media.Colors.Gray,
                    Opacity = 0.5,
                    ShadowDepth = 3,
                    Direction = 315
                };
                popup.Child = border;
                border.Child = panel;

                popup.Opened += (s, e) => Opened?.Invoke(this, e);
                popup.Closed += (s, e) => Closed?.Invoke(this, e);
            }
        }
    }
}