Elasticsearch 搜索属性不为空

Elasticsearch 按属性搜索，发现它不为 null。我这样做了.Query(s => s.Bool(b => b.Must(m => m.Exists(e => e.Field(f => f.fields.EventId.Id)))))，但答案中没有文档。elastic本身就有这样的文档："fields": { "address": "https://0.0.0.0:81", "EventId": { "Id": 14,"Name": "ListeningOnAddress"},. 这是来自应用程序的 Logger 日志。用于映射本身的类是通过 Visual Studio 2022 中的特殊插入创建的。

public class _Source
{
    [Date(Format = DateFormat.strict_date_hour_minute_second, Name = "@timestamp")]
    public DateTime Timestamp { get; set; }    
    public string level { get; set; }
    public string messageTemplate { get; set; }
    public string message { get; set; }    
    public Fields fields { get; set; }
}

public class Fields
{
    public string status { get; set; }
    public string chargePoint { get; set; }      
    public Eventid EventId { get; set; }    
    public string SourceContext { get; set; }
    public string ActionId { get; set; }
    public string ActionName { get; set; }
    public string RequestId { get; set; }
    public string RequestPath { get; set; }
    public string ConnectionId { get; set; }
    public string MachineName { get; set; }
    public object UserId { get; set; }
    public string RemoteIpAddress { get; set; }
    public string Environment { get; set; }
}

public class Eventid
{        
    public int Id { get; set; }
}