C#删除datagridview中选中的多行

private void button3_Click(object sender, EventArgs e)
        {
            int k = dataGridView1.SelectedRows.Count;
            if (MessageBox.Show("您确认要删除这" + Convert.ToString(k) + "项吗？", "系统提示", MessageBoxButtons.YesNo, MessageBoxIcon.Question) == DialogResult.No)//给出提示
            {

            }
            else
            {
                 if (k != dataGridView1.Rows.Count - 2)//因为还有一行为统计行所以减2
                {

                    for (int i = k; i >= 1; i--)//从下往上删，避免沙漏效应
                    {

                        dataGridView1.Rows.RemoveAt(dataGridView1.SelectedRows[i - 1].Index);
                    }
                }
                else
                {
                    dataGridView1.Rows.Clear();
                }          
            }