Elasticsearch .NET Client 8.11.0更新别名代码编译错误求助

问题描述 #

使用Elasticsearch .NET客户端（8.11.0版本），成功索引文档后编写更新别名的代码时，遇到编译错误：
Error CS1729 : 'IndexAlias' does not contain a constructor that takes 1 arguments

原代码片段：

using System.Collections.ObjectModel;
using Company Namespace;
using Elastic.Clients.Elasticsearch;
using Elastic.Clients.Elasticsearch.IndexManagement;
using Action = Elastic.Clients.Elasticsearch.IndexManagement.Action;

public Task<UpdateAliasesResponse> UpdateAlias(string indexName)
{
    var addAction = new AddAction();
    addAction.Index = IndexName.From<string>(indexName);
    addAction.Alias = new IndexAlias(ALIAS_NAME);
    var actions = new Collection<Action>();
    actions.Add(addAction);
    UpdateAliasesRequest request = new UpdateAliasesRequest();
    request.Actions = actions;

    return this._elasticsearchClient.Indices.UpdateAliasesAsync(request);
}

SDK引用：

<PackageReference Include="Elastic.Clients.Elasticsearch" Version="8.11.0" />

修正方案 #

错误原因是Elastic.Clients.Elasticsearch 8.x版本中，IndexAlias类未提供接收单个字符串参数的构造函数。以下两种方式均可解决问题：

方式一：直接赋值别名字符串（推荐） #

无需实例化IndexAlias，直接将别名字符串赋值给Alias属性：

using System.Collections.ObjectModel;
using CompanyNamespace; // 注意：原代码中"Company Namespace"含空格，需改为合法命名空间
using Elastic.Clients.Elasticsearch;
using Elastic.Clients.Elasticsearch.IndexManagement;
using Action = Elastic.Clients.Elasticsearch.IndexManagement.Action;

public Task<UpdateAliasesResponse> UpdateAlias(string indexName)
{
    var addAction = new AddAction();
    addAction.Index = IndexName.From<string>(indexName);
    // 直接赋值别名字符串
    addAction.Alias = ALIAS_NAME;
    var actions = new Collection<Action>();
    actions.Add(addAction);
    UpdateAliasesRequest request = new UpdateAliasesRequest();
    request.Actions = actions;

    return this._elasticsearchClient.Indices.UpdateAliasesAsync(request);
}

方式二：使用无参构造函数设置Name属性 #

通过IndexAlias无参构造函数创建实例后，设置其Name属性：

using System.Collections.ObjectModel;
using CompanyNamespace;
using Elastic.Clients.Elasticsearch;
using Elastic.Clients.Elasticsearch.IndexManagement;
using Action = Elastic.Clients.Elasticsearch.IndexManagement.Action;

public Task<UpdateAliasesResponse> UpdateAlias(string indexName)
{
    var addAction = new AddAction();
    addAction.Index = IndexName.From<string>(indexName);
    // 无参构造实例后设置Name属性
    addAction.Alias = new IndexAlias { Name = ALIAS_NAME };
    var actions = new Collection<Action>();
    actions.Add(addAction);
    UpdateAliasesRequest request = new UpdateAliasesRequest();
    request.Actions = actions;

    return this._elasticsearchClient.Indices.UpdateAliasesAsync(request);
}

额外说明 #

原代码中的Company Namespace包含空格，属于非法C#命名空间，实际使用时需替换为项目的合法命名空间。

内容的提问来源于stack exchange，提问作者silentsudo