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();
}
}