private void Form1_Load(object sender,EventArgs e)
{
  listBox1.MouseDown += new MouseEventHandler(listBox1_MouseDown);
}

void listBox1_MouseDown(object sender,MouseEventArgs e)
{
  if (e.Button == MouseButtons.Right)
  {
    MessageBox.Show("Right Click");
  }
}

您还可以让设计人员通过选择ListBox并在“属性”窗口中双击MouseDown事件(单击闪电)为您连接事件.