From 050e4f5b6f07a026ea451ce0f38406430b3efad3 Mon Sep 17 00:00:00 2001
From: Lorenz Stechauner <lorenz.stechauner@necronda.net>
Date: Fri, 14 Jun 2024 13:24:00 +0200
Subject: [PATCH] ControlUtils: Allow RenewItemsSource for ListBox to reselect
 all items

---
 Elwig/Helpers/ControlUtils.cs | 34 +++++++++++++++++++++++-----------
 1 file changed, 23 insertions(+), 11 deletions(-)

diff --git a/Elwig/Helpers/ControlUtils.cs b/Elwig/Helpers/ControlUtils.cs
index 89f210a..45c2bdf 100644
--- a/Elwig/Helpers/ControlUtils.cs
+++ b/Elwig/Helpers/ControlUtils.cs
@@ -134,19 +134,31 @@ namespace Elwig.Helpers {
         public static void RenewItemsSource(ListBox listBox, IEnumerable? source, SelectionChangedEventHandler? handler = null, RenewSourceDefault def = RenewSourceDefault.None) {
             if (listBox.ItemsSource == source)
                 return;
-            var selectedId = Utils.GetEntityIdentifier(listBox.SelectedItem);
-            object? selItem = null;
-            if (selectedId != 0 && source != null)
-                selItem = source.Cast<object>().FirstOrDefault(i => selectedId.Equals(Utils.GetEntityIdentifier(i)));
-            if (source != null && selItem == null) {
-                if ((def == RenewSourceDefault.IfOnly && source.Cast<object>().Count() == 1) || def == RenewSourceDefault.First) {
-                    selItem = source.Cast<object>().FirstOrDefault();
+            if (listBox.SelectionMode == SelectionMode.Single) {
+                var selectedId = Utils.GetEntityIdentifier(listBox.SelectedItem);
+                object? selItem = null;
+                if (selectedId != 0 && source != null)
+                    selItem = source.Cast<object>().FirstOrDefault(i => selectedId.Equals(Utils.GetEntityIdentifier(i)));
+                if (source != null && selItem == null) {
+                    if ((def == RenewSourceDefault.IfOnly && source.Cast<object>().Count() == 1) || def == RenewSourceDefault.First) {
+                        selItem = source.Cast<object>().FirstOrDefault();
+                    }
                 }
+                if (handler != null && selItem != null) listBox.SelectionChanged -= handler;
+                listBox.ItemsSource = source;
+                if (handler != null && selItem != null) listBox.SelectionChanged += handler;
+                listBox.SelectedItem = selItem;
+            } else {
+                var selectedIds = listBox.SelectedItems.Cast<object>().Select(Utils.GetEntityIdentifier).ToList();
+                if (handler != null && selectedIds != null) listBox.SelectionChanged -= handler;
+                listBox.ItemsSource = source;
+                if (source != null && selectedIds != null) {
+                    listBox.SelectedItems.Clear();
+                    foreach (var i in source.Cast<object>().Where(i => selectedIds.Contains(Utils.GetEntityIdentifier(i))))
+                        listBox.SelectedItems.Add(i);
+                }
+                if (handler != null && selectedIds != null) listBox.SelectionChanged += handler;
             }
-            if (handler != null && selItem != null) listBox.SelectionChanged -= handler;
-            listBox.ItemsSource = source;
-            if (handler != null && selItem != null) listBox.SelectionChanged += handler;
-            listBox.SelectedItem = selItem;
         }
 
         public static object? GetItemFromSource(IEnumerable source, int? hash) {