弹性搜索映射器附件，索引时抛出嵌套错误

我最近开始使用弹性搜索，我正在尝试使用mapper附件插件为pdf文档编制索引，在编制索引时遇到错误值不能为null参数名称：index，是否有人可以帮助修复此

以下是索引代码：

    static void Main(string[] args)
    {

        var connectionSettings = new ConnectionSettings(new Uri("http://localhost:9200/"));
        var elasticClient = new ElasticClient(connectionSettings);

        elasticClient.CreateIndex("pdf-index", c => c.AddMapping<Document>(m => m.MapFromAttributes()));

        var attachment = new Attachment
        {
            Content = Convert.ToBase64String(File.ReadAllBytes("test.pdf")),
            ContentType = "application/pdf",
            Name = "test.pdf"
        };

        var doc = new Document()
        {
            Id = 1,
            Title = "test",
            File = attachment
        };

        elasticClient.Index(doc);
    }

    public class Attachment
    {
        [ElasticProperty(Name = "_content")]
        public string Content { get; set; }

        [ElasticProperty(Name = "_content_type")]
        public string ContentType { get; set; }

        [ElasticProperty(Name = "_name")]
        public string Name { get; set; }
    }

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

        public string Title { get; set; }

        [ElasticProperty(Type = FieldType.Attachment, TermVector = TermVectorOption.WithPositionsOffsets, Store = true)]
        public Attachment File { get; set; }

    }

---

我猜你忘了在弹性搜索连接设置中添加默认索引

var uri = new Uri("http://localhost:9200/");
var connectionSettings = new ConnectionSettings(uri, defaultIndex: "my-application");

var elasticClient=新的ElasticClientconnectionSettings

更多信息请点击这里

当然，默认索引是可选的。然后在索引文档时必须指定索引。 e、 g

client.Index(doc, i => i
     .Index(index)
     .Type(type)     
);