如何在选定的主项目更改时刷新详细信息

我有一个主详细信息表单与2个网格:客户=主，订单=细节。当从主网格中选择新客户时，如何刷新详细信息?下面是我的代码:

public partial class Form1 : Form
    {
        AutoLotEntities context = new AutoLotEntities();
        BindingSource customerBindingSource;
        BindingSource orderBindingSource;
        public Form1()
        {
            InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            customerBindingSource = new BindingSource();
            orderBindingSource = new BindingSource();
            customerBindingSource.DataSource = context.Customers;
            orderBindingSource.DataMember = "Orders";
            orderBindingSource.DataSource = customerBindingSource.DataSource;
            grdCustomers.DataSource = customerBindingSource;
            grdOrders.DataSource = orderBindingSource;
        }
    }

我设法在IDE生成的form . designer .cs代码的帮助下做到这一点，但我想用非生成的代码手工完成，看看这个东西是如何工作的