我试图在ASP.NET Core MVC Web API中将一个对象序列化为JSON，然后再将其返回给用户。该对象来自EF Core数据库，控制器是使用scaffolding生成的，其中包含了我添加的一些include属性，我希望将这些属性保留到我设置的自定义MaxDepth。我理解this was a feature added in System.Text.Json in .NET 6，并且我希望避免使用Newtonsoft.JSON。
在查阅了C#文档之后，我在Program.cs中添加了以下内容来配置ReferenceHandler：

builder.Services.AddControllers()
    .AddJsonOptions(o =>
    {
        o.JsonSerializerOptions.ReferenceHandler
            = ReferenceHandler.IgnoreCycles;
        o.JsonSerializerOptions.MaxDepth = 5;
    });

然而，在我的Program.cs中添加以下代码后，我在尝试访问端点时仍然收到错误：

System.Text.Json.JsonException: A possible object cycle was detected. This can either be due to a cycle or if the object depth is larger than the maximum allowed depth of 5. Consider using ReferenceHandler.Preserve on JsonSerializerOptions to support cycles.

将ReferenceHandler设置为“保留”也不起作用：

System.Text.Json.JsonException: The object or value could not be serialized. Path: $.Asset.AssetOdometers.
 ---> System.InvalidOperationException: CurrentDepth (5) is equal to or larger than the maximum allowed depth of 5. Cannot write the next JSON object or array.

我的GET端点如下所示：

// GET: api/Pmtasks
        [HttpGet]
        public async Task<ActionResult<IEnumerable<Pmtask>>> GetPmtasks()
        {
          if (_context.Pmtasks == null)
          {
              return NotFound();
          }
            return await _context.Pmtasks
                .Include(t => t.Asset)
                .Include(t => t.Task)
                .Include(t => t.PmscheduleType)
                .ToListAsync();
        }