如何使用Newtonsoft序列化生成指定结构的嵌套JSON

1 修正实体类 #

你现有的实体类仅需调整Line类，补充目标JSON中小计行独有的Amountlin字段即可：

public class Line
{
    public string Id { get; set; }
    public int LineNum { get; set; }
    public string Description { get; set; }
    public int Amount { get; set; }
    // 新增可空的Amountlin字段，仅小计行赋值
    public int? Amountlin { get; set; }
    public string DetailType { get; set; }
    public SalesItemLineDetail SalesItemLineDetail { get; set; }
    public SubTotalLineDetail SubTotalLineDetail { get; set; }
}

2 组装嵌套对象 #

按照从内层到外层的顺序构建对象即可，示例代码完全匹配你给出的目标JSON结构：

// 1. 构建销售行的内层对象
var salesItemLineDetail = new SalesItemLineDetail
{
    ItemRef = new ItemRef { value = "3", name = "Test:Test Item" },
    UnitPrice = 100,
    Qty = 1,
    ItemAccountRef = new ItemAccountRef { value = "6", name = "Sales" },
    TaxCodeRef = new TaxCodeRef { value = "6" }
};
// 2. 构建第一行（销售行）
var salesLine = new Line
{
    Id = "1",
    LineNum = 1,
    Description = "Test Sales Description",
    Amount = 100,
    DetailType = "SalesItemLineDetail",
    SalesItemLineDetail = salesItemLineDetail
};
// 3. 构建第二行（小计行）
var subTotalLine = new Line
{
    Amountlin = 0,
    DetailType = "SubTotalLineDetail",
    SubTotalLineDetail = new SubTotalLineDetail()
};
// 4. 构建TxnTaxDetail相关对象
var taxLineDetail = new TaxLineDetail
{
    TaxRateRef = new TaxRateRef { value = "7" },
    PercentBased = true,
    TaxPercent = 20,
    NetAmountTaxable = 0
};
var taxLine = new TaxLine
{
    Amount = 0,
    DetailType = "TaxLineDetail",
    TaxLineDetail = taxLineDetail
};
var txnTaxDetail = new TxnTaxDetail
{
    TotalTax = 0,
    TaxLine = new List<TaxLine> { taxLine }
};
// 5. 构建地址、客户相关对象
var customerRef = new CustomerRef { value = "2", name = "Test Company" };
var billAddr = new BillAddr
{
    Id = "3",
    Line1 = "21 TEST TEST",
    Line2 = "TEST",
    City = "TEST",
    Country = "United Kingdom",
    PostalCode = "POSTCODE"
};
var shipAddr = new ShipAddr
{
    Id = "3",
    Line1 = "21 TEST TEST",
    Line2 = "TEST",
    City = "TEST",
    Country = "United Kingdom",
    PostalCode = "POSTCODE"
};
// 6. 组装根对象
var root = new Root
{
    Line = new List<Line> { salesLine, subTotalLine },
    TxnTaxDetail = txnTaxDetail,
    CustomerRef = customerRef,
    BillAddr = billAddr,
    ShipAddr = shipAddr
};

3 序列化配置 #

序列化时需添加忽略null值的配置，避免未赋值的属性（比如销售行的Amountlin、小计行的Id等）输出为null，匹配目标JSON格式：

using Newtonsoft.Json;

var serializeSettings = new JsonSerializerSettings
{
    // 忽略值为null的属性
    NullValueHandling = NullValueHandling.Ignore,
    // 可选：格式化输出JSON，方便调试
    Formatting = Formatting.Indented
};
string jsonResult = JsonConvert.SerializeObject(root, serializeSettings);

输出的jsonResult就完全符合你给出的目标JSON格式。

内容的提问来源于stack exchange，提问作者Chris Waine