VB.NET中WSDL复杂类型重复属性赋值问题求助

你的思路完全正确，问题出在addressline属性——它是数组类型，但默认状态下是空引用（Nothing），直接通过索引赋值必然会抛出"object reference not set to instance of an object"错误，必须先实例化指定长度的数组才能使用。

修正后的代码示例 #

Dim DeliveryAddress As New deliveryaddressType

' 先实例化长度为2的字符串数组（对应最多2条地址线的要求）
DeliveryAddress.addressline = New String(1) {}
' 给数组元素赋值
DeliveryAddress.addressline(0) = "address line 1"
DeliveryAddress.addressline(1) = "address line 2" ' 可选，不需要的话可以留空

' 其他单一属性正常赋值
DeliveryAddress.city = "city"
DeliveryAddress.zip = "zip"
DeliveryAddress.state = "state"
DeliveryAddress.country = "USA"

补充说明 #

如果WSDL生成的addressline是List(Of String)而非数组（部分WSDL工具会自动将可重复元素转为泛型集合），处理方式略有不同：

Dim DeliveryAddress As New deliveryaddressType
DeliveryAddress.addressline = New List(Of String)()
DeliveryAddress.addressline.Add("address line 1")
DeliveryAddress.addressline.Add("address line 2") ' 可选

内容的提问来源于stack exchange，提问作者bjg1993