A*在向成本排序字典中添加节点时，Pathfinding AI处于冻结状态

我正试图在一个简单的四向移动网格上构建一个基于A Star Pathfinding的AI，然而每当我试图将节点添加到比较字典中并对其进行排序时，它都会在dictionary.add上崩溃。我不完全确定为什么，有人能发现这个缺陷吗？

    void DirectionFinder()
{
    // Find Target Point //
    GetBoardPosition();
    BuildOrReBuildPawnRefBoard();
    bool IsTrue = false;
    int Serial = lastSquare.Location.Serial;
    // Get the Serial Keys of the nodes that are neighboring this node //
    bool TestNode = NodesClosed.ContainsKey(Serial);
    Dictionary<int, Node> SortArray = new Dictionary<int, Node>();
    SortArray.Clear();
    if (TestNode) 
    {
        Node ScanNode = NodesClosed[Serial];
        // Get the Number of Neighbors I have //
        int TestNumNeighbors = ScanNode.NeighborNodes.Count;
        // Set up a Loop that will go through these nodes and get the lowest-scored movement node //
        for (int loop = 0; loop < TestNumNeighbors; loop++)
        {
            int ScanNodePointX = ScanNode.NeighborNodes[loop].X;
            int ScanNodePointY = ScanNode.NeighborNodes[loop].Y;
            int ScanTestSerial = System_GameController.Instance.NodeArray[ScanNodePointX, ScanNodePointY].Location.Serial;
            bool IsNodeOpen = NodesOpen.ContainsKey(ScanTestSerial);
            if (IsNodeOpen)
            {
                Debug.Log("This Node is Open:" + ScanTestSerial);
                Node CompareNode = NodesOpen[ScanTestSerial];
                int CostOfNode = CompareNode.TotalCost;
                SortArray.Add(CostOfNode, CompareNode);
            }
        }
    }
}

它一直到"CostOfNode"。这很管用。。。。然后在尝试添加到SortArray时中断。

int CostOfNode = CompareNode.TotalCost;
SortArray.Add(CostOfNode, CompareNode);