c# - 返回 Datacontract 中的结构数组

Question

我需要在 Datacontract 中返回一个结构数组。我做不到。设置数组的值时收到错误消息。

这是 Datacontract 声明：

    [DataContract] 
    public class invoice_data
    {
        [DataMember]
        public Invoice_Body_Item[] invoice_body;
    }


    [StructLayout(LayoutKind.Sequential)]
    public struct Invoice_Body_Item
    {
        public string Item_Description;
        public decimal Item_Value;
    }
}

这是方法代码：

invoice_data Invoice = new invoice_data();
object tr_bl = svr.GetInvoiceData(inputparams.ck, svr.Confirm(inputparams.ck));

for (int i = ((Array)(((object[])(tr_bl))[1])).GetLowerBound(0); i <= ((Array)(((object[])(tr_bl))[1])).GetUpperBound(0); i++)
{
    Invoice.invoice_body[i].Item_Description = (string)((object[])(((object[])(((object[])(tr_bl))[1]))[i]))[0];
    Invoice.invoice_body[i].Item_Value = (decimal)((object[])(((object[])(((object[])(tr_bl))[1]))[i]))[1]; 
}
                        }

在这一行中，我收到错误“对象引用未设置为对象的实例”。

Invoice.invoice_body[i].Item_Description = (string)((object[])(((object[])(((object[])(tr_bl))[1]))[i]))[0];

Answer 1

您的结构也应该用[DataContract]+ 装饰它的成员[DataMember]：

[StructLayout(LayoutKind.Sequential)]
[DataContract]
public struct Invoice_Body_Item
{
    [DataMember]
    public string Item_Description;
    [DataMember]
    public decimal Item_Value;
}

或者，您可以使用[KnownTypeAttribute(typeof(Invoice_Body_Item))]