...

Chrono/Server/Components/Pages/DeckBuilder.razor

@@ -83,7 +83,7 @@
             {
                 var count = CountInDeck(card.Name);
                 var maxed = count >= 3;
-                <div class="browser-card @(count > 0 ? "in-deck" : "") @(maxed ? "maxed" : "")"
+                <div @key="card.Name" class="browser-card @(count > 0 ? "in-deck" : "") @(maxed ? "maxed" : "")"
                      @onclick="() => AddCard(card)"
                      title="@(count > 0 ? $"{card.Name} ({count}/3)" : card.Name)">
                     <div class="browser-card-img">
@@ -314,7 +314,13 @@
         }
     }
 
-    private int CountInDeck(string name) => deckCards.Count(c => c == name);
+    private Dictionary<string, int> _deckCounts = new();
+
+    private void RebuildDeckCounts() =>
+        _deckCounts = deckCards.GroupBy(n => n).ToDictionary(g => g.Key, g => g.Count());
+
+    private int CountInDeck(string name) =>
+        _deckCounts.TryGetValue(name, out var c) ? c : 0;
 
     protected override async Task OnParametersSetAsync()
     {
@@ -339,23 +345,27 @@
         deckNotes = deck.Notes ?? "";
         deckCards = new List<string>(deck.Cards);
         divers = new List<string>(deck.Divers);
+        RebuildDeckCounts();
     }
 
     private void AddCard(CardData card)
     {
         if (CountInDeck(card.Name) >= 3) return;
         deckCards.Add(card.Name);
+        RebuildDeckCounts();
     }
 
     private void RemoveCard(string name)
     {
         var idx = deckCards.LastIndexOf(name);
         if (idx >= 0) deckCards.RemoveAt(idx);
+        RebuildDeckCounts();
     }
 
     private void ClearDeck()
     {
         deckCards.Clear();
+        RebuildDeckCounts();
     }
 
     private void OpenDiverPicker(int slot)