问datagridview报错，隐藏至空时程序终止，大佬求教？

namespace 读写
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        string path = @"D:\log\log.xlsx";

        private void button1_Click(object sender, EventArgs e)
        {
            var rows = MiniExcel.Query<Test>(path).ToList();
            dataGridView1.DataSource = rows;

        }





        internal class Test
        {
            public int Year { get; set; }
            public int moon { get; set; }
            public int time { get; set; }
            public string cellid { get; set; }

        }
        int count = 0;


        private void textBox1_TextChanged(object sender, EventArgs e)
        {
            var rows = MiniExcel.Query<Test>(path).ToList();
            dataGridView1.DataSource = rows;
            if (textBox1.Text != "")
            {
                foreach (DataGridViewRow row in dataGridView1.Rows)
                {
                    for (int i = 0; i < row.Cells.Count; i++)
                    {
                        if (row.Cells[i].Value.ToString().Contains(textBox1.Text))
                        {
                            count = count + 1;
                        }
                    }
                    if (count == 0)
                    {
                        row.Visible = false;
                    }
                    count = 0;
                }
            }
            else
            {
                for (int i = 0; i < dataGridView1.Rows.Count; i++)
                {
                    dataGridView1.Rows[i].Visible = true;
                }
            }


        }

        private void dataGridView1_CellContentClick(object sender, DataGridViewCellEventArgs e)
        {
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }
    }
}