C#窗体中为什么打不开已经保存了的棋局啊？有谁可以看下吗

openchess_Click() 打不开 savechess_Click()中保存的棋局，大概结构是这样的

namespace 练习1
{
class public partial class Form1 : Form

{
    private void savechess_Click(object sender, EventArgs e)
    {
        SaveFileDialog s = new SaveFileDialog();
        s.Filter = "五子棋|*.wzq";
        s.ShowDialog();
        FileStream fs = new FileStream(s.FileName, FileMode.Create, FileAccess.Write);
        Chess c = new Chess(chesslist, formqipan);
        BinaryFormatter bf = new BinaryFormatter();
        bf.Serialize(fs, c);
        fs.Close();
    }

    private void openchess_Click(object sender, EventArgs e)
    {
        OpenFileDialog o = new OpenFileDialog();
        o.Filter = "五子棋|*.wzq";
        if (o.ShowDialog() == DialogResult.OK)
        {
            FileStream fs = new FileStream(o.FileName, FileMode.Open, FileAccess.Read);
            //Chess c = new Chess(chesslist, formqipan);
            BinaryFormatter bf = new BinaryFormatter();
            Chess c = (Chess)bf.Deserialize(fs);
            fs.Close();
        }
        Invalidate();
    }
}

[Serializable]
public struct Point
{
    public int X;
    public int Y;
}

[Serializable]
class Chess
{
    public int width = 640;
    public int height = 600;

    public ChessState[,] qipan = new ChessState[15, 15];
    public List<Point> pointlist = new List<Point>(500);

    public Chess(List<Point> l, ChessState[,] fq)
    {
        pointlist = l;
        qipan = fq;
    }

}

}

Chess c = (Chess)bf.Deserialize(fs); 之后没有对c进行任何操作。