【解決方法】VB.NET を C# に変換する – 助けてください!

カードゲームを C# に変換しています

非常に頻繁に表示される1つのケースでは、エラーが発生します

エラー CS1061 ‘ItemCollection’ には ‘Item’ の定義が含まれておらず、タイプ ‘ItemCollection’ の最初の引数を取るアクセス可能なアイテム拡張メソッドが見つかりませんでした (使用ディレクティブまたはアセンブリ参照が欠落している可能性があります)。

エラー CS1061 “ItemCollection” には “Item” の定義が含まれておらず、”ItemCollection” 型の初期引数を受け入れるアクセス可能な項目拡張メソッドが見つかりませんでした (using ディレクティブまたはアセンブリ参照が欠落している可能性があります)。

「withBlock.Item(n)」で問題が発生

VB:

<Extension()>
      Public Function SelectFirstCardCommonCheck_ALL(hc As HandCards,
                                               Wnd As MainWindow, ByVal CardsPanel As Object,
                                               TrumpID As Integer, LeadSuitID As Integer) As PlayingCard

          Dim sHand As String
          Dim FindCard As PlayingCard
          Dim ACP As New AutoCardPlay(Wnd.sk.trumpCard, Wnd)

          sHand = hc.GetHandString

          With CardsPanel.Items
              sHand = String.Empty
              If .Count > 0 Then
                  For n = 0 To .Count - 1
                      If Wnd.iTricks > 5 Then
                          If NonTrumpCards(hc, TrumpID) IsNot Nothing Then
                              If NonTrumpCards(hc, TrumpID).Contains(GetEichelHighestPlayableCard(Wnd.TrickHistory)) Then
                                  If .Item(n).ToString = GetEichelHighestPlayableCard(Wnd.TrickHistory) Then FindCard = .Item(n)
                              End If
                              If NonTrumpCards(hc, TrumpID).Contains(GetLaubHighestPlayableCard(Wnd.TrickHistory)) Then
                                  If .Item(n).ToString = GetLaubHighestPlayableCard(Wnd.TrickHistory) Then FindCard = .Item(n)
                              End If
                              If NonTrumpCards(hc, TrumpID).Contains(GetSchellHighestPlayableCard(Wnd.TrickHistory)) Then
                                  If .Item(n).ToString = GetSchellHighestPlayableCard(Wnd.TrickHistory) Then FindCard = .Item(n)
                              End If
                          Else
                              If hc.GetHighestCard(LeadSuitID, TrumpID) IsNot Nothing Then
                                  If .Item(n).ToString = hc.GetHighestCard(LeadSuitID, TrumpID).ToString Then
                                      FindCard = CardsPanel.Items.Item(n)
                                  End If
                              End If
                          End If
                          If FindCard Is Nothing Then
                              Dim curCard As PlayingCard =
                                  ACP.SelectBestFirstCard(CardsPanel, hc.PlayerID, Wnd.sk.declarer, Wnd.GameStatus,
                                                      sHand, TrumpID, hc, Wnd, LeadSuitID)
                              If curCard IsNot Nothing AndAlso curCard.CardType <> TrumpID Then
                                  FindCard = curCard
                                  If FindCard.CardValue = 2 Or FindCard.CardValue = 3 Then Wnd.sk.leadSuit = TrumpID
                                  If FindCard.CardValue = 2 Or FindCard.CardValue = 3 Then LeadSuitID = TrumpID
                              End If
                          End If

                      Else

                          If FindCard Is Nothing Then
                              Dim curCard As PlayingCard =
                                  ACP.SelectBestFirstCard(CardsPanel, hc.PlayerID, Wnd.sk.declarer, Wnd.GameStatus,
                                                      sHand, TrumpID, hc, Wnd, LeadSuitID)
                              If curCard IsNot Nothing AndAlso curCard.CardType <> TrumpID Then
                                  FindCard = curCard
                                  'If FindCard IsNot Nothing Then Debug.Print("ALL 77 FindCard: " & FindCard.ToString)
                                  If FindCard.CardValue = 2 Or FindCard.CardValue = 3 Then Wnd.sk.leadSuit = TrumpID
                                  If FindCard.CardValue = 2 Or FindCard.CardValue = 3 Then LeadSuitID = TrumpID
                              End If
                          End If

                      End If
                  Next
              End If
          End With

          If FindCard IsNot Nothing Then Return FindCard

      End Function

私が試したこと：

public static PlayingCard SelectFirstCardCommonCheck_ALL(this HandCards hc, MainWindow Wnd, ListBox CardsPanel, int TrumpID, int LeadSuitID)
 {

     string sHand;
     var FindCard = default(PlayingCard);
     var ACP = new AutoCardPlay(Wnd.sk.trumpCard, Wnd);

     sHand = hc.GetHandString();

     {
         var withBlock =  CardsPanel.Items;
         sHand = string.Empty;
         if (Conversions.ToBoolean(Operators.ConditionalCompareObjectGreater(withBlock.Count, 0, false)))
         {
             for (int n = 0, loopTo = Conversions.ToInteger(Operators.SubtractObject(withBlock.Count, 1)); n <= loopTo; n++)
             {
                 if (Wnd.iTricks > 5)
                 {
                     if (NonTrumpCards(hc, TrumpID) is not null)
                     {
                         if (NonTrumpCards(hc, TrumpID).Contains(Extensions_TrickMonitoring.GetEichelHighestPlayableCard(Wnd.TrickHistory)))
                         {
                             if ((withBlock.Item(n).ToString() ?? "") == (Extensions_TrickMonitoring.GetEichelHighestPlayableCard(Wnd.TrickHistory) ?? ""))
                                 FindCard = (PlayingCard)withBlock.Item(n);
                         }
                         if (NonTrumpCards(hc, TrumpID).Contains(Extensions_TrickMonitoring.GetLaubHighestPlayableCard(Wnd.TrickHistory)))
                         {
                             if ((withBlock.Item(n).ToString() ?? "") == (Extensions_TrickMonitoring.GetLaubHighestPlayableCard(Wnd.TrickHistory) ?? ""))
                                 FindCard = (PlayingCard)withBlock.Item(n);
                         }
                         if (NonTrumpCards(hc, TrumpID).Contains(Extensions_TrickMonitoring.GetSchellHighestPlayableCard(Wnd.TrickHistory)))
                         {
                             if ((withBlock.Item(n).ToString() ?? "") == (Extensions_TrickMonitoring.GetSchellHighestPlayableCard(Wnd.TrickHistory) ?? ""))
                                 FindCard = (PlayingCard)withBlock.Item(n);
                         }
                     }
                     else if (hc.GetHighestCard(LeadSuitID, TrumpID) is not null)
                     {
                         if ((withBlock.Item(n).ToString() ?? "") == (hc.GetHighestCard(LeadSuitID, TrumpID).ToString() ?? ""))
                         {
                             FindCard = (PlayingCard)CardsPanel.Items.Item(n);
                         }
                     }
                     if (FindCard is null)
                     {
                         var curCard = ACP.SelectBestFirstCard(CardsPanel, hc.PlayerID, Wnd.sk.declarer, Wnd.GameStatus, sHand, TrumpID, hc, Wnd, LeadSuitID);
                         if (curCard is not null && (int)curCard.CardType != TrumpID)
                         {
                             FindCard = curCard;
                             if ((int)FindCard.CardValue == 2 | (int)FindCard.CardValue == 3)
                                 Wnd.sk.leadSuit = TrumpID;
                             if ((int)FindCard.CardValue == 2 | (int)FindCard.CardValue == 3)
                                 LeadSuitID = TrumpID;
                         }
                     }
                 }


                 else if (FindCard is null)
                 {
                     var curCard = ACP.SelectBestFirstCard(CardsPanel, hc.PlayerID, Wnd.sk.declarer, Wnd.GameStatus, sHand, TrumpID, hc, Wnd, LeadSuitID);
                     if (curCard is not null && (int)curCard.CardType != TrumpID)
                     {
                         FindCard = curCard;
                         // If FindCard IsNot Nothing Then Debug.Print("ALL 77 FindCard: " & FindCard.ToString)
                         if ((int)FindCard.CardValue == 2 | (int)FindCard.CardValue == 3)
                             Wnd.sk.leadSuit = TrumpID;
                         if ((int)FindCard.CardValue == 2 | (int)FindCard.CardValue == 3)
                             LeadSuitID = TrumpID;
                     }

                 }
             }
         }
     }

     if (FindCard is not null)
         return FindCard;
     return default;

 }