PowerShell/src/Microsoft.Management.UI.Internal/ManagementList/Common/DismissiblePopup.cs

// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.

using System;
using System.Diagnostics;
using System.Windows;
using System.Windows.Automation;
using System.Windows.Controls.Primitives;
using System.Windows.Data;
using System.Windows.Input;
using System.Windows.Media;

namespace Microsoft.Management.UI.Internal
{
    /// <content>
    /// Partial class implementation for DismissiblePopup control.
    /// </content>
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.MSInternal", "CA903:InternalNamespaceShouldNotContainPublicTypes")]
    public partial class DismissiblePopup : Popup
    {
        /// <summary>
        /// Constructs an instance of DismissablePopup.
        /// </summary>
        public DismissiblePopup() : base()
        {
            // nothing
        }

        private delegate void FocusChildDelegate();

        /// <summary>
        /// Responds to the condition in which the value of the IsOpen property changes from false to true.
        /// </summary>
        /// <param name="e">The event arguments.</param>
        protected override void OnOpened(EventArgs e)
        {
            base.OnOpened(e);

            if (this.FocusChildOnOpen)
            {
                this.Dispatcher.BeginInvoke(
                                            System.Windows.Threading.DispatcherPriority.Loaded,
                                            new FocusChildDelegate(this.FocusChild));
            }

            this.SetupAutomationIdBinding();
        }

        /// <summary>
        /// Responds when the value of the IsOpen property changes from to true to false.
        /// </summary>
        /// <param name="e">The event arguments.</param>
        protected override void OnClosed(EventArgs e)
        {
            base.OnClosed(e);

            if (this.SetFocusOnClose)
            {
                // Find a control to set focus on.
                if (this.SetFocusOnCloseElement != null)
                {
                    // The focus target is set explicitly.
                    this.SetFocus(this.SetFocusOnCloseElement);
                }
                else if (this.PlacementTarget != null)
                {
                    // Use PlacementTarget as a first chance option.
                    this.SetFocus(this.PlacementTarget);
                }
                else
                {
                    // Use parent UIObject when neither FocusOnCloseTarget nor PlacementTarget is set.
                    UIElement parent = this.Parent as UIElement;
                    if (parent != null)
                    {
                        this.SetFocus(parent);
                    }
                }
            }
        }

        private void SetFocus(UIElement element)
        {
            if (element.Focusable)
            {
                element.Focus();
            }
            else
            {
                element.MoveFocus(new TraversalRequest(FocusNavigationDirection.First));
            }
        }

        private void SetupAutomationIdBinding()
        {
            var popupRoot = this.FindPopupRoot();

            var binding = new Binding();
            binding.Source = this;
            binding.Path = new PropertyPath(AutomationProperties.AutomationIdProperty);
            popupRoot.SetBinding(AutomationProperties.AutomationIdProperty, binding);
        }

        private FrameworkElement FindPopupRoot()
        {
            DependencyObject element = this.Child;

            while (element.GetType().Name.Equals("PopupRoot", StringComparison.Ordinal) == false)
            {
                element = VisualTreeHelper.GetParent(element);
            }

            Debug.Assert(element != null, "element not null");

            return (FrameworkElement)element;
        }

        /// <summary>
        /// Provides class handling for the KeyDown routed event that occurs when the user presses a key while this control has focus.
        /// </summary>
        /// <param name="e">The event data.</param>
        protected override void OnKeyDown(System.Windows.Input.KeyEventArgs e)
        {
            ////
            // Close the popup if ESC is pressed
            ////
            if (e.Key == System.Windows.Input.Key.Escape && this.CloseOnEscape)
            {
                this.IsOpen = false;
            }
            else
            {
                base.OnKeyDown(e);
            }
        }

        partial void OnDismissPopupExecutedImplementation(ExecutedRoutedEventArgs e)
        {
            this.IsOpen = false;
        }

        private void FocusChild()
        {
            if (this.Child != null)
            {
                this.Child.MoveFocus(new TraversalRequest(FocusNavigationDirection.First));
            }
        }
    }
}