datarow()数据处理问题!在线等!

[独行侠周游世界]

我的控件combox,中cbCustomers_SelectedIndexChanged
代码如下
'声明存储客户号的字符变量
Dim SelectedCustomerID As String
'变量赋值取得cbx控件的选取值
SelectedCustomerID = cbCustomers.SelectedValue.ToString()

'声明一个用来保存客户记录的数据行变量
Dim drSelectedCustomer As DataRow
drSelectedCustomer = DsNorthwind1.Customers.FindByCustomerID(SelectedCustomerID)

'声明一个用来保存相关记录的数据行数组
Dim draOrders As DataRow()
draOrders = drSelectedCustomer.GetChildRows("CustomersOrders")

'在窗体标题中显示数组的长度(订单数)和客户的id号 & _ 续行符号
Me.Text = draOrders.Length.ToString() & " order for " & _
SelectedCustomerID

'清空lb控件
lbOrders.Items.Clear()
rtbDetails.Text = ""

'将所有相关的订单orderID添加到列表框
Dim drOrder As DataRow
For Each drOrder In draOrders
lbOrders.Items.Add(draOrders("OrderID"))
这地方报错说string转换integer错误,不知道如何处理,就是要将orderid的值加载到lborders控件中