Automatically bind pascal case c# model from snake case JSON in WebApi

Question

I am trying to bind my PascalCased c# model from snake_cased JSON in WebApi v2 (full framework, not dot net core).

Here\'s my api:

public class MyAp         


        

Answer 1

Well, you should be able to do it using a custom JsonConverter to read your data. Using the deserialization provided in Manojs' answer, you could create a DefaultContractResolver that would create a custom deserialization when the class has a SnakeCasedAttribute specified above.

The ContractResolver would look like the following

public class SnakeCaseContractResolver : DefaultContractResolver {
  public new static readonly SnakeCaseContractResolver Instance = new SnakeCaseContractResolver();

  protected override JsonContract CreateContract(Type objectType) {
    JsonContract contract = base.CreateContract(objectType);

    if (objectType?.GetCustomAttributes(true).OfType().Any() == true) {
      contract.Converter = new SnakeCaseConverter();
    }

    return contract;
  }
}

The SnakeCaseConverter would be something like this?

public class SnakeCaseConverter : JsonConverter {
  public override bool CanConvert(Type objectType) => objectType.GetCustomAttributes(true).OfType().Any() == true;
  private static string ConvertFromSnakeCase(string snakeCased) {
    return string.Join("", snakeCased.Split('_').Select(part => part.Substring(0, 1).ToUpper() + part.Substring(1)));
  }

  public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer) {
    var target = Activator.CreateInstance( objectType );
    var jobject = JObject.Load(reader);

    foreach (var property in jobject.Properties()) {
      var propName = ConvertFromSnakeCase(property.Name);
      var prop = objectType.GetProperty(propName);
      if (prop == null || !prop.CanWrite) {
        continue;
      }
      prop.SetValue(target, property.Value.ToObject(prop.PropertyType, serializer));
    }
    return target;
  }

  public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer) {
    throw new NotImplementedException();
  }
}

And then you could annotate your dto class using this attribute (which is just a placeholder)

[SnakeCased]
public class InputObjectDTO {
  public string FullName { get; set; }
  public int TotalPrice { get; set; }
}

and for reference, this is the used attribute

[AttributeUsage(AttributeTargets.Class)]
public class SnakeCasedAttribute : Attribute {
  public SnakeCasedAttribute() {
    // intended blank
  }
}

One more thing to notice is that in your current form the JSON converter would throw an error ("20.00" is not an int), but I am going to guess that from here you can handle that part yourself :)

And for a complete reference, you could see the working version in this dotnetfiddle