inital

FasdDesktopUi/Basics/Models/IFocusInvoker.cs

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+using FasdDesktopUi.Basics.Helper;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows;
+using System.Windows.Controls;
+using static C4IT.Logging.cLogManager;
+
+namespace FasdDesktopUi.Basics.Models
+{
+    public interface IFocusInvoker
+    {
+        int? ParentIndex { get; }
+        UIElement ParentElement { get; }
+    }
+
+    public static class cFocusInvoker
+    {
+        public static EventHandler GotFocus = delegate { };
+        public static EventHandler LostFocus = delegate { };
+
+        private static void ReAllocate(this IFocusInvoker focusInvoker)
+        {
+            try
+            {
+                if (!(focusInvoker is FrameworkElement focusInvokerElement))
+                    return;
+
+                if (focusInvoker.ParentElement is null)
+                    return;
+
+                if (focusInvokerElement.Parent is Panel actualParentPanel)
+                    actualParentPanel.Children.Remove(focusInvokerElement);
+                else if (focusInvokerElement.Parent is Decorator actualParentDecorator)
+                    actualParentDecorator.Child = null;
+                else
+                    return;
+
+                if (focusInvoker.ParentElement is Panel parentPanel)
+                {
+                    if (focusInvoker.ParentIndex != null)
+                    {
+                        parentPanel.Children.RemoveAt(focusInvoker.ParentIndex.Value);
+                        parentPanel.Children.Insert(focusInvoker.ParentIndex.Value, focusInvokerElement);
+                    }
+                    else
+                    {
+                        parentPanel.Children.Add(focusInvokerElement);
+                    }
+                }
+                else if (focusInvoker.ParentElement is Decorator parentDecorator)
+                {
+                    parentDecorator.Child = focusInvokerElement;
+                }
+            }
+            catch (Exception E)
+            {
+                LogException(E);
+            }
+        }
+
+        private static void ReAllocate(this FrameworkElement focusInvokerElement)
+        {
+            try
+            {
+                var preFocusParent = GetPreFocusParent(focusInvokerElement);
+
+                if (preFocusParent is null)
+                    return;
+
+                if (focusInvokerElement.Parent is Panel actualParentPanel)
+                    actualParentPanel.Children.Remove(focusInvokerElement);
+                else if (focusInvokerElement.Parent is Decorator actualParentDecorator)
+                    actualParentDecorator.Child = null;
+                else
+                    return;
+
+                if (preFocusParent is Panel parentPanel)
+                {
+                    var preFocusChildIndex = GetPreFocusChildIndex(focusInvokerElement);
+
+                    if (preFocusChildIndex != null)
+                    {
+                        parentPanel.Children.RemoveAt(preFocusChildIndex.Value);
+                        parentPanel.Children.Insert(preFocusChildIndex.Value, focusInvokerElement);
+                    }
+                    else
+                    {
+                        parentPanel.Children.Add(focusInvokerElement);
+                    }
+                }
+                else if (preFocusParent is Decorator parentDecorator)
+                {
+                    parentDecorator.Child = focusInvokerElement;
+                }
+            }
+            catch (Exception E)
+            {
+                LogException(E);
+            }
+        }
+
+        public static void InvokeGotFocus(object sender, EventArgs e)
+        {
+            try
+            {
+                if (sender is FrameworkElement senderElement)
+                {
+                    SetPreFocusParent(senderElement, senderElement.Parent);
+
+                    if (senderElement.Parent is Panel actualParentPanel)
+                        SetPreFocusChildIndex(senderElement, actualParentPanel.Children.IndexOf(senderElement));
+                }
+
+                GotFocus?.Invoke(sender, e);
+            }
+            catch (Exception E)
+            {
+                LogException(E);
+            }
+        }
+
+        public static void InvokeLostFocus(object sender, EventArgs e)
+        {
+            LostFocus?.Invoke(sender, e);
+
+            if (sender is IFocusInvoker focusSender)
+                focusSender.ReAllocate();
+            else if (sender is FrameworkElement senderElement)
+                senderElement.ReAllocate();
+        }
+
+        #region Attached Properties
+
+        #region PreFocusChildIndex
+
+        private static int? GetPreFocusChildIndex(DependencyObject obj)
+        {
+            return (int?)obj.GetValue(PreFocusChildIndexProperty);
+        }
+
+        private static void SetPreFocusChildIndex(DependencyObject obj, int? value)
+        {
+            obj.SetValue(PreFocusChildIndexProperty, value);
+        }
+
+        public static readonly DependencyProperty PreFocusChildIndexProperty =
+            DependencyProperty.RegisterAttached("PreFocusChildIndex", typeof(int?), typeof(UIElement), new PropertyMetadata(null));
+
+        #endregion
+
+        #region PreFocusParent
+
+        private static DependencyObject GetPreFocusParent(DependencyObject obj)
+        {
+            return (DependencyObject)obj.GetValue(PreFocusParentProperty);
+        }
+
+        private static void SetPreFocusParent(DependencyObject obj, DependencyObject value)
+        {
+            obj.SetValue(PreFocusParentProperty, value);
+        }
+
+        public static readonly DependencyProperty PreFocusParentProperty =
+            DependencyProperty.RegisterAttached("PreFocusParent", typeof(DependencyObject), typeof(UIElement), new PropertyMetadata(null));
+
+        #endregion
+
+        #endregion
+    }
+}