private void Form1_Closing(object sender, System.ComponentModel.CancelEventArgs e)
{
if(MessageBox.Show("确定关闭?","Form",MessageBoxButtons.OKCancel) == DialogResult.Cancel)
e.Cancel = true;
}
{
if(MessageBox.Show("确定关闭?","Form",MessageBoxButtons.OKCancel) == DialogResult.Cancel)
e.Cancel = true;
}