在嵌套(ElasticSearch)中使用来自searchResponse的storedFields时出错
在嵌套(ElasticSearch)中使用来自searchResponse的storedFields时出错
提问于 2019-05-12 20:34:38
我需要将来自NEST (ElasticSearch)的搜索结果绑定到ASP.NET (Webform)中的Gridview。
代码我使用NEST从ElasticSearch获得结果：
public class Address
{
public int SN { get; set; }
public string JLN { get; set; }
}
protected void BtnSearch_Clicked(object sender, EventArgs e)
{
string SearchValue = txtSearchValue.Text;
string es_host = System.Configuration.ConfigurationManager.AppSettings["cnStringIP"];
string es_port = System.Configuration.ConfigurationManager.AppSettings["cnStringPort"];
string es_index = System.Configuration.ConfigurationManager.AppSettings["cnStringIndex"];
var settings = new ConnectionSettings(new Uri("http://" + es_host + ":" + es_port + ""))
.DefaultIndex("masterlist*");
var client = new ElasticClient(settings);
var searchResponse = client.Search<Address>(s => s
.Index("masterlist*")
.From(0)
.Size(10)
.Query(q => q
.QueryString(qs => qs
.Query("JLN:\""+ SearchValue +"\"")
)
)
);
var address = searchResponse.Documents.ToList();
ESGridview.DataSource = address;
ESGridview.DataBind();
}有了这段代码，网格视图可以自动生成正确标题的两个字段"SN“和"JLN"，它可以自动生成10行(我在搜索语法中将大小限制为最大10行)，但列中的数据为空。
我找到了另一篇有这个链接的帖子
检查此链接后，我将代码更改为：
string SearchValue = txtSearchValue.Text;
string es_host = System.Configuration.ConfigurationManager.AppSettings["cnStringIP"];
string es_port = System.Configuration.ConfigurationManager.AppSettings["cnStringPort"];
string es_index = System.Configuration.ConfigurationManager.AppSettings["cnStringIndex"];
var settings = new ConnectionSettings(new Uri("http://" + es_host + ":" + es_port + ""))
.DefaultIndex("masterlist*");
var client = new ElasticClient(settings);
var searchResponse = client.Search<Address>(s => s
.StoredFields(sf => sf
.Fields(
f => f.SN,
f => f.JLN
)
)
.From(0)
.Size(10)
.Query(q => q
.QueryString(qs => qs
.Query("JLN:\""+ SearchValue +"\"")
)
)
);
foreach (var fieldValues in searchResponse.Fields)
{
var document = new
{
SN = fieldValues.ValueOf<Address, int>(p => p.SN),
JLN = fieldValues.Values<Address, string>(p => p.JLN)
};
}
var address = searchResponse.Documents;
var count = "MaxScore" + searchResponse.MaxScore;
ESGridview.DataSource = address;
ESGridview.DataBind();但是当我在整个foreach (var...)区域上从开始运行代码时，我得到了一个错误：
System.NullReferenceException：“对象引用未设置为对象的实例。”
有没有人可以教我如何解决这个问题或我做错的任何事情？非常感谢~
ElasticSearch 7.0.1 NEST 7.0.0 C# ASP.NET (Webform)
回答 1
Stack Overflow用户
发布于 2019-05-13 01:28:47
我已经解决了我的问题。下面的代码是如何从ElasticSearch获取searchResult，并使用NEST将数据绑定到ASP.NET中的Gridview。
public class Address
{
[Text(Name = "SN")]
public string SN { get; set; }
[Text(Name = "JLN")]
public string JLN { get; set; }
}
protected void BtnSearch_Clicked(object sender, EventArgs e)
{
string SearchValue = txtSearchValue.Text;
string es_host = System.Configuration.ConfigurationManager.AppSettings["cnStringIP"];
string es_port = System.Configuration.ConfigurationManager.AppSettings["cnStringPort"];
string es_index = System.Configuration.ConfigurationManager.AppSettings["cnStringIndex"];
var settings = new ConnectionSettings(new Uri("http://" + es_host + ":" + es_port + ""))
.DefaultIndex("masterlist*");
var client = new ElasticClient(settings);
var searchResponse = client.Search<Address>(s => s
.From(0)
.Size(100)
.Query(q => q
.QueryString(qs => qs
.Query("JLN:\"" + SearchValue + "\"")
)
)
);
var address = searchResponse.Documents.ToList();
ESGridview.DataSource = address;
ESGridview.DataBind();
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/56099290
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