[BUG] Can't send complex object as data in EventGridEvent

[Sarah-Aly]

Describe the bug
Trying the new Event Grid SDK, sending data as a string in the event, serialized successfully, But trying to send a complex object as the data in the event, I get empty data in the consumer

Expected behavior
Be able to send complex objects as data in EventGridEvent

Actual behavior (include Exception or Stack Trace)
complex object data is not serialized correctly & we get empty data in the consumer (event grid trigger azure function)

To Reproduce

    class data
    {
        string name;
        string value;
        public data(string name, string value)
        {
            this.name = name;
            this.value = value;
        }
    }

    class Program
    {
        static Uri endpoint = new Uri("<EG-TOPIC-ENDPOINT>");
        static AzureKeyCredential azureKey = new AzureKeyCredential("<AEG-SAS-KEY>");
        static void Main(string[] args)
        {
            EventGridPublisherClient eventGridPublisherClient = new EventGridPublisherClient(endpoint, azureKey);
            var events = new List<EventGridEvent>();
            // this sends empty data
            events.Add(new EventGridEvent(new data("test3", "event grid schema"), "subject 3", "eventType 3", "1.0"));
            // this sends correct data
            events.Add(new EventGridEvent("ping pong", "subject 4", "eventType 4", "1.0"));
            eventGridPublisherClient.SendEvents(events);
        }
    }

Environment:

• Name and version of the Library package used: Azure.Messaging.EventGrid -Version 4.0.0-beta.1

[jsquire]

Hi @Sarah-Aly. Thank you for your feedback; tagging and routing to the team member best able to assist.

[JoshLove-msft]

@Sarah-Aly, it looks like the issue is that your type is using fields rather than properties.
Also the properties would need to be public for serialization to work with the default serializer - System.Text.Json.
See https://docs.microsoft.com/en-us/dotnet/standard/serialization/system-text-json-how-to#serialization-behavior for current behavior.

It looks like in .NET 5.0, field support is being added to System.Text.Json dotnet/runtime#41313

[JoshLove-msft]

We should update the documentation to make it clear what the default constraints w.r.t. serialization are.

[Sarah-Aly]

This works. Thanks @JoshLove-msft.
Closing the issue.