鉴于此类:
public class Thing
{
public string Alpha { get; set; }
public string Beta { get; set; }
}
我需要序列化 Thing 的任意子类,这些子类本身可以添加 Thing 属性。例如...
public class SomeThing : Thing
{
public string Delta {get; set; }
public Thing ThisThing { get; set; }
public Thing ThatThing { get; set; }
}
这很简单,使用 Newtonsoft Json.NET 将 SomeThing 类序列化为:
{
alpha: "x",
beta: "x",
delta: "x",
thisThing: {
alpha: "y",
beta: "y"
},
thatThing: {
alpha: "z",
beta: "z"
}
}
不过,我想要做的是这样的(不更改 Thing 或 SomeThing 类):
{
alpha: "x",
beta: "x",
delta: "x",
things: {
thisThing: {
alpha: "y",
beta: "y"
},
thatThing: {
alpha: "z",
beta: "z"
}
}
也就是说,我想将所有 Thing 属性收集到名为 things 的子对象中。
另一个例子:
public class SomeThingElse : Thing
{
public int Gamma {get; set; }
public Thing Epsilon { get; set; }
}
...将序列化为
{
alpha: "x",
beta: "x",
gamma: 42,
things: {
epsilon: {
alpha: "y",
beta: "y"
}
}
}
通过创建契约(Contract)解析器,我可以轻松地剥离单个事物属性,并让非事物自行序列化。但我不知道如何创建 things 属性并将其放回我剥离的属性中:
public class MyContractResolver : CamelCasePropertyNamesContractResolver
{
protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
{
var properties = base.CreateProperties(type, memberSerialization);
// grab the properties that are NOT a Thing
var toCreate = properties.Where(p => !typeof(Thing).IsAssignableFrom(p.PropertyType)).ToList();
// grab the properties that ARE a Thing
var toGroup = properties.Where(p => typeof(Thing).IsAssignableFrom(p.PropertyType)).ToList();
// create the new things property to stuff toGroup into
var things = new JsonProperty
{
PropertyName = "things"
};
// THIS IS WHERE I'M STUCK...
// TODO: somehow stuff toGroup into "things"
// put the group back along with the non-thing properties
toCreate.Add(things);
// return the re-combined set of properties
return toCreate;
}
}
我按如下方式使用此解析器(针对此问题进行了简化):
static void Main(string[] args)
{
var st = new SomeThing
{
Alpha = "x",
Beta = "x",
Delta = "x",
ThisThing = new Thing() {Alpha = "y", Beta = "y"},
ThatThing = new Thing() {Alpha = "z", Beta = "z"}
};
var settings = new JsonSerializerSettings
{
ContractResolver = new MyContractResolver(),
Formatting = Formatting.Indented
};
var result = JsonConvert.SerializeObject(st, settings);
Console.WriteLine(result);
}
哪个产生
{
alpha: "x",
beta: "x",
delta: "x"
}
请注意,即使我创建并添加了一个名称为“things”的 JsonProperty,它也不会出现。我的希望是我只需要填写契约(Contract)解析器中 TODO 附近的空白。
或者也许我走错了方向。你能帮我吗?
最佳答案
可以将自定义 IContractResolver
与自定义 IValueProvider
结合使用来完成您想要的操作。试试这个:
public class MyContractResolver : CamelCasePropertyNamesContractResolver
{
protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
{
var properties = base.CreateProperties(type, memberSerialization);
// if the type is a Thing and has child properties that are things...
if (typeof(Thing).IsAssignableFrom(type) &&
properties.Any(p => typeof(Thing).IsAssignableFrom(p.PropertyType)))
{
// grab only the properties that are NOT a Thing
properties = properties
.Where(p => !typeof(Thing).IsAssignableFrom(p.PropertyType))
.ToList();
// Create a virtual "things" property to group the remaining properties
// into; associate the new property with a ValueProvider that will do
// the actual grouping when the containing object is serialized
properties.Add(new JsonProperty
{
DeclaringType = type,
PropertyType = typeof(Dictionary<string, object>),
PropertyName = "things",
ValueProvider = new ThingValueProvider(),
Readable = true,
Writable = false
});
}
return properties;
}
private class ThingValueProvider : IValueProvider
{
public object GetValue(object target)
{
// target should be a Thing; we want to get its Thing properties
// and group them into a Dictionary.
return target.GetType().GetProperties()
.Where(p => typeof(Thing).IsAssignableFrom(p.PropertyType))
.ToDictionary(p => p.Name, p => p.GetValue(target));
}
public void SetValue(object target, object value)
{
throw new NotImplementedException();
}
}
}
演示:
class Program
{
static void Main(string[] args)
{
SomeThing st = new SomeThing
{
Alpha = "x.a",
Beta = "x.b",
ThisThing = new Thing { Alpha = "y.a", Beta = "y.b" },
ThatThing = new SomeThingElse
{
Alpha = "z.a",
Beta = "z.b",
Delta = 42,
Epsilon = new Thing { Alpha = "e.a", Beta = "e.b" }
}
};
JsonSerializerSettings settings = new JsonSerializerSettings();
settings.ContractResolver = new MyContractResolver();
settings.Formatting = Formatting.Indented;
string json = JsonConvert.SerializeObject(st, settings);
Console.WriteLine(json);
}
}
public class Thing
{
public string Alpha { get; set; }
public string Beta { get; set; }
}
public class SomeThing : Thing
{
public Thing ThisThing { get; set; }
public Thing ThatThing { get; set; }
}
public class SomeThingElse : Thing
{
public int Delta { get; set; }
public Thing Epsilon { get; set; }
}
输出:
{
"alpha": "x.a",
"beta": "x.b",
"things": {
"thisThing": {
"alpha": "y.a",
"beta": "y.b"
},
"thatThing": {
"delta": 42,
"alpha": "z.a",
"beta": "z.b",
"things": {
"epsilon": {
"alpha": "e.a",
"beta": "e.b"
}
}
}
}
}
关于c# - 序列化为 JSON 时如何将属性分组到子对象中,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/25795241/