相关疑难解决方法(0)

我刚刚将我的MongoDB从2.5.0更新到2.7.0.Visual Studio告诉我,当我想创建这样的索引时:

protected override Task OnPerformMaintenanceAsync(CancellationToken cancellationToken) =>
  NotificationLogs.Indexes.CreateOneAsync(Builders<NotificationLog>.IndexKeys.Ascending(_ => _.TimestampUtc));

已经过时了.他们希望我们使用CreateIndexModel https://mongodb.github.io/mongo-csharp-driver/2.6/apidocs/html/T_MongoDB_Driver_CreateIndexModel_1.htm

唯一的问题是我找不到一个能够实现同样功能的例子.

我试过了:

protected Task OnPerformMaintenanceTestAsync(CancellationToken cancellationToken)
{
  // Old approach
  // var builder = Builders<NotificationLog>.IndexKeys.Ascending(x => x.TimestampUtc);

  // New approach
  var indexModel = new CreateIndexModel<NotificationLog>(nameof(NotificationLog.TimestampUtc));

  return NotificationLogs.Indexes.CreateOneAsync(indexModel);
}

我一直得到以下异常:

System.FormatException: 'JSON reader was expecting a value but found 'TimestampUtc'.'