winform程序關閉界面時彈出提示框

void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
    if (MessageBox.Show(
            "窗口關閉后，數據即將丟失！是否現在關閉窗口",
            "提示", 
            MessageBoxButtons.OKCancel, 
            MessageBoxIcon.Question) != DialogResult.OK)
            {
                e.Cancel = true;
                return;
            }
}