UnityEventSample.cs

using UnityEngine;
using UnityEngine.EventSystems;

public class SampleEventData : BaseEventData
{
    public string SampleStr { get; private set; }
    public SampleEventData(EventSystem eventSystem, string sampleStr) : base(eventSystem)
    {
        SampleStr = sampleStr;
    }
}

public interface ISampleHandler : IEventSystemHandler
{
    void OnSampleCode(SampleEventData eventData);
}

public class SampleInputModule : BaseInputModule
{
    public GameObject TargetObject { get; set; }
    public override void Process()
    {
        if (TargetObject != null)
            ExecuteEvents.Execute<ISampleHandler>(TargetObject, new SampleEventData(eventSystem, "sample data"),
                (handler, eventData) => handler.OnSampleCode(ExecuteEvents.ValidateEventData<SampleEventData>(eventData)));
    }
}

public class SampleEventMB : MonoBehaviour, ISampleHandler
{
    public void OnSampleCode(SampleEventData eventData)
    {
        Debug.Log(eventData.SampleStr);
    }
}