c# - 如何在转换为 json 时格式化对象中仅为字符串的属性？

Question

实例类型不明确。我以 Foo 为例。我有一个格式化方法和一个类，如下所示，

public string FormatMethod(string s){
    //for example pattern ++
    return "++" + s + "++"; 
}

public class Foo{
    public int FooId {get;set;}
    public string Name {get;set;}
    public string Desciption {get;set;}
}

var foo = new Foo{ FooId = 1, Name = "FooName", Description = "Bla bla bla" };
// or
var list = new List<Foo>();
list.Add(foo);

var json = JsonConvert.SerializeObject(list);
//or
var jsonlist = JsonConvert.SerializeObject(foo);

我希望将对象或列表中的字符串属性在转换为 json 时发送到格式化方法，

我希望 json 结果如下所示，

json 结果

 {"FooId": 1 , "Name": "++FooName++", "Description" : "++Bla bla bla++" }

或作为列表

[{"FooId": 1 , "Name": "++FooName++", "Description" : "++Bla bla bla++" }]

我该怎么做？

编辑:

我想在对象被序列化时应用任何模式，例如名称为'FooName'，序列化后需要为'++FooName++'。

我认为可以使用 myconverter 来完成，但是怎么做呢？

例如:

public class MyConverter : JsonConverter
    {
        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
        {
            // need to do something in here, I don't know what to do.
        }

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            throw new NotImplementedException();
        }

        public override bool CanConvert(Type objectType)
        {
            throw new NotImplementedException();
        }
    } 

Answer 1

转换器:

class StringFormatConverter : JsonConverter
{
    public string Format { get; set; }

    public override void WriteJson (JsonWriter writer, object value, JsonSerializer serializer)
    {
        writer.WriteValue(string.Format(Format, value));
    }

    public override object ReadJson (JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        throw new NotSupportedException();
    }

    public override bool CanConvert (Type objectType)
    {
        return objectType == typeof(string);
    }
}

用法:

Console.WriteLine(JsonConvert.SerializeObject(new List<Foo> {
    new Foo { FooId = 1, Name = "FooName", Description = "Bla bla bla" }
}, new JsonSerializerSettings {
    Converters = { new StringFormatConverter { Format = "++{0}++" } }
}));

输出:

[{"FooId":1,"Name":"++FooName++","Description":"++Bla bla bla++"}]

如果需要限制对特定属性的字符串修改，可以使用JsonConverterAttribute和 JsonPropertyAttribute.ItemConverterType (并从 JsonSerializerSettings 中删除“全局”转换器)。