JSonConverter how to make generic deserialization

Question

I have been able to do a custom Converter that transforms to a list of interfaces.

Here my custom converter:

public class InvoiceDetailConverter : JsonConverter {
    public override bool CanConvert(Type objectType) {
        //assume we can convert to anything for now
        return true;
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer) {
        List<InvoiceDetail> data = serializer.Deserialize<List<InvoiceDetail>>(reader);

        // now loop to make the proper list
        List<IInvoiceDetail> result = new List<IInvoiceDetail>();
        foreach (IInvoiceDetail d in data) {
            result.Add(d);
        }

        return result;
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer) {
        //use the default serialization - it works fine
        serializer.Serialize(writer, value);
    }
}

What I would like is to make this generic like

public class InvoiceDetailConverter <TConcrete, TInterface> : JsonConverter {
    public override bool CanConvert(Type objectType) {
        //assume we can convert to anything for now
        return true;
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer) {
        List<TConcrete> data = serializer.Deserialize<List<TConcrete>>(reader);

        // now loop to make the proper list
        List<TInterface> result = new List<TInterface>();
        foreach (TInterface d in data) {
            result.Add(d);
        }
        return result;
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer) {
        //use the default serialization - it works fine
        serializer.Serialize(writer, value);
    }
}

At the End in my object it will be used like this:

public class test{
    [JsonConverter(typeof(InvoiceDetailConverter<InvoiceDetail, IInvoiceDetail>))]
    public List<IInvoiceDetail> InvoiceDetail { get; set; }
}

Is it possible to convert like this, as the above code won't compile. I'm using .NET Core.

Answer 1

我相信你快到了，只需指定TConcrete和之间的依赖关系TInterface：

public class InvoiceDetailConverter<TConcrete, TInterface> : JsonConverter
    where TConcrete : TInterface    // <------------------------------------------ add this
{
    // ..........
}

在这里，您可以找到使用以下对象的通用转换器类成功反序列化的演示：

public class test
{
    [JsonConverter(typeof(InvoiceDetailConverter<InvoiceDetail, IInvoiceDetail>))]
    public List<IInvoiceDetail> InvoiceDetail { get; set; }

    [JsonConverter(typeof(InvoiceDetailConverter<VatDetail, IVatDetail>))]
    public List<IVatDetail> VatDetail { get; set; }
}