I believe the answer you linked is probably your best option.
So create a converter as per the anwser.
class TrimmingConverter : JsonConverter
{
public override bool CanConvert(Type objectType)
{
return objectType == typeof(string);
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
if (reader.TokenType == JsonToken.String)
if (reader.Value != null)
return (reader.Value as string).Trim();
return reader.Value;
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
var text = (string)value;
if (text == null)
writer.WriteNull();
else
writer.WriteValue(text.Trim());
}
}
And then register it in your ConfigureServices
method in your Startup
class like so:
public void ConfigureServices(IServiceCollection services)
{
services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1)
.AddJsonOptions(a => a.SerializerSettings.Converters.Add(new TrimmingConverter()));
}