---

//初始化退出标识
private DialogResult result = DialogResult.No;
//Yes关闭窗口，No最小化窗口
private void Form1_FormClosing(object sender, FormClosingEventArgs e) {
        if (result == DialogResult.Yes) {
            e.Cancel = false;
            Application.Exit();
        } else {
            e.Cancel = true;
            this.Hide();
            this.Visible = false;
        }
    }
    //关闭按钮，给result赋值
private void btnExit_Click(object sender, EventArgs e) {
    result = MessageBox.Show("确认退出窗口吗？", "提示", MessageBoxButtons.YesNo, MessageBoxIcon.Information);
    Application.Exit();
}