public class GameGrid<T>
{
    protected class Coordinates
    {
        public int Row { get; set; }
        public int Col { get; set; }
        public int RightDiagRow { get; set; }
        public int RightDiagPos { get; set; }
        public int LeftDiagRow { get; set; }
        public int LeftDiagPos { get; set; }
        public Coordinates()
        {
            Row = -1;
            Col = -1;
            RightDiagRow = -1;
            RightDiagPos = -1;
            LeftDiagRow = -1;
            LeftDiagPos = -1;
        }
        public Coordinates(int row, int col, int rightDiagRow, int rightDiagPos, int leftDiagRow, int leftDiagPos)
        {
            Row = row;
            Col = col;
            RightDiagRow = rightDiagRow;
            RightDiagPos = rightDiagPos;
            LeftDiagRow = leftDiagRow;
            LeftDiagPos = leftDiagPos;
        }
    }
    protected class Cell
    {
        public T Value { get; set; }
        public Coordinates Location { get; set; }
        public Cell()
        {
            Value = default(T);
            Location = new Coordinates();
        }
        public Cell(int row, int col,int rightDiagRow,int rightDiagPos, int leftDiagRow,int leftDiagPos)
        {
            Value = default(T);
            Location = new Coordinates(row, col, rightDiagRow, rightDiagPos, leftDiagRow, leftDiagPos);
        }
        public override string ToString()
        {
            return Value.ToString();
        }
    }
    const int DEFAULT_GRID_SIZE = 3;
    protected int GridSize { get; set; }
    protected Cell[][] Rows { get; set; }
    protected Cell[][] Cols { get; set; }
    protected Cell[][] RightDiagRows { get; set; }
    protected Cell[][] LeftDiagRows { get; set; }

    /// <summary>
    /// New GameGrid set to a default size of 3
    /// </summary>
    protected GameGrid()
    {
        GridSize = DEFAULT_GRID_SIZE;
        InitGrid();
    }
    /// <summary>
    /// New GameGrid set to gridSize
    /// </summary>
    protected GameGrid(int gridSize)
    {
        GridSize = gridSize;
        InitGrid();
    }
    private void InitGrid()
    {
        Rows = new Cell[GridSize][];
        Cols = new Cell[GridSize][];
        int diagSize = (GridSize * 2) - 1;
        RightDiagRows = new Cell[diagSize][];
        LeftDiagRows = new Cell[diagSize][];
        for(int i = 0; i < GridSize;i++)
        {
            Rows[i] = new Cell[GridSize];
            Cols[i] = new Cell[GridSize];
            RightDiagRows[i] = new Cell[GridSize];
            LeftDiagRows[i] = new Cell[GridSize];
        }
        for(int i = GridSize; i < diagSize;i++)
        {
            RightDiagRows[i] = new Cell[GridSize];
            LeftDiagRows[i] = new Cell[GridSize];
        }
        for (int row = 0; row < GridSize; row++)
        {
            for (int col = 0; col < GridSize; col++)
            {
                int rightDiagRow = ((GridSize * 2) - 2) - (row + col);
                int rightDiagPos = rightDiagRow < GridSize ? (GridSize - 1) - col : row;
                int leftDiagRow = Math.Abs((row - col) - (GridSize - 1));
                int leftDiagPos = leftDiagRow < GridSize ? col : row;
                Cell newCell = new Cell(row, col, rightDiagRow, rightDiagPos, leftDiagRow, leftDiagPos);
                Rows[row][col] = newCell;
                Cols[col][row] = newCell;
                RightDiagRows[rightDiagRow][rightDiagPos] = newCell;
                LeftDiagRows[leftDiagRow][leftDiagPos] = newCell;
            }
        }
        for(int i = 0; i < RightDiagRows.Length;i++)
        {
            RightDiagRows[i] = RightDiagRows[i].Where(x => x != null).ToArray();
            LeftDiagRows[i] = LeftDiagRows[i].Where(x => x != null).ToArray();
        }
    }
}

public class TicTacToe : GameGrid<char>

public TicTacToe():base()