.net core操作MongoDB

山德鲁 發表於 2023-1-29 16:18:00

<h2 id="前言">前言</h2>
现实中认识的一个搞java(<s>百万富婆</s>)的大佬,已经转行做抖音主播了,搞技术的只能赶在年前再水一篇博客,不足之处欢迎拍砖,以免误人子弟,呔,真是太难受了 <img src="https://img2023.cnblogs.com/blog/772322/202301/772322-20230107170752864-1644844153.jpg" alt="image" loading="lazy">
<h2 id="环境准备">环境准备</h2>
<blockquote>
<ul>
<li>.net core 3.1</li>
<li>MongoDB</li>
<li>Navicat Premium 16</li>

</ul>

</blockquote>
<h3 id="创建项目">创建项目</h3>
<blockquote>
1.选择ASP.NET Core Web API 项目模板

</blockquote>
<img src="https://img2023.cnblogs.com/blog/772322/202301/772322-20230107162958530-406321051.png" alt="image" class="medium-zoom-image" loading="lazy">
<blockquote>
2.配置项目信息项目名称,项目路径

</blockquote>
<img src="https://img2023.cnblogs.com/blog/772322/202301/772322-20230107163011158-173823834.png" alt="image" class="medium-zoom-image" loading="lazy">
<blockquote>
3.配置项目其它信息,这里选择使用.net core 3.1 不配置https

</blockquote>
<img src="https://img2023.cnblogs.com/blog/772322/202301/772322-20230107163038480-1022864056.png" alt="image" class="medium-zoom-image" loading="lazy">
<h3 id="添加依赖">添加依赖</h3>
<blockquote>
1.获取MongoDB.Driver包版本 2.18.0

</blockquote>
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-xml">方案A. install-package MongoDB.Driver
方案B. nuget包管理工具搜索 MongoDB.Driver
方案C. 选中项目,双击,添加
<ItemGroup>
<PackageReference Include="MongoDB.Driver" Version="2.18.0" />
</ItemGroup>
</code></pre>
<h3 id="注册中间件">注册中间件</h3>
<blockquote>
1.添加配置文件
</blockquote>
<pre class="highlighter-hljs"><code class="language-json highlighter-hljs hljs">"MongoDB": {
"ConnName": "mongodb://root:123456@127.0.0.1:27017/",
"DatabaseName": "test"
}
</code></pre>
<blockquote>
2.添加配置类
</blockquote>
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-csharp">public class MongoDBConfig
{
/// <summary>
/// 连接字符串
/// </summary>
public string ConnName { get; set; }

/// <summary>
/// 数据库名称
/// </summary>
public string DatabaseName { get; set; }
}
</code></pre>
<blockquote>
3.注册配置文件与中间件
</blockquote>
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-csharp">//读取配置文件
var mongoDBOptions = Configuration.GetSection("MongoDB").Get<MongoDBConfig>();

//注册配置
services.Configure<MongoDBConfig>(this.Configuration.GetSection("MongoDB"));

//注册中间件
services.AddSingleton(new MongoClient(mongoDBOptions.ConnName));
</code></pre>
其实就是注册了一个mongodb的客户端实例,然后用这个客户端实例来实现crud,如果你想优雅点(<s>强迫症</s>),也可以自定义一个拓展,来注册这个实例,这是一个通用技巧,后面使用到的类请自行注册
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-csharp">public static class MongoDBExtensions
{
public static void AddMongoDB(this IServiceCollection services, Action<MongoDBConfig> setupAction)
{
 if (setupAction == null)
 {
 throw new ArgumentNullException(nameof(setupAction));
 }
 var options = new MongoDBConfig();
 setupAction(options);
 services.Configure(setupAction);
 services.AddSingleton(services.AddSingleton(new MongoClient(options.ConnName)));
}
}
</code></pre>
使用拓展,来注册中间件
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-javascript">var mongoDBOptions = Configuration.GetSection("MongoDB").Get<MongoDBConfig>();
services.AddMongoDB(m =>
{
m.ConnName = mongoDBOptions.ConnName;
m.DatabaseName = mongoDBOptions.DatabaseName;
});
</code></pre>
<h3 id="封装基础操作">封装基础操作</h3>
最常用的办法,就是弄个DBHelper类,这种简单粗暴的方式,在.net core里使用并不优雅(<s>网上教程太多了,不想重复的水</s>),这里模拟常规的仓储模式,进行演示
<blockquote>
1.创建 Service,Repertoty,Model 文件夹 2.创建 BaseDbContext 类

</blockquote>
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-csharp">public class BaseDbContext
{
private readonly IMongoDatabase _database;
public BaseDbContext(MongoClient client, IOptions<MongoDBConfig> options)
{
 //决定使用哪个库
 _database = client.GetDatabase(options.Value.DatabaseName);
}

/// <summary>
/// 数据库对象
/// </summary>
public IMongoDatabase MongoDatabase { get{ return _database; } }
}
</code></pre>
如果项目只操作一个数据库,直接在基类里指定操作的数据库即可,如果需要操作多个数据库,可以再新建一个子类(TestDbContext),在子类里指定要操作的数据库 前面我已经注册了mongodb的客户端跟配置文件,所以在Startup类下,可以直接注册这个类,容器会自动管理这些依赖
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-csharp">services.AddSingleton(typeof(BaseDbContext));
</code></pre>
如果你想更优雅点(<s>强迫症</s>),可以创建一个IBaseDbContext 接口,在接口里定义相关的规范
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-xml">services.AddSingleton<IBaseDbContext>();
</code></pre>
<blockquote>
3.创建 BaseRepertoty 类
</blockquote>
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-typescript">public class BaseRepertoty<T> where T : class, new()
{
private readonly IMongoDatabase _database;

private readonly string _collName;

public BaseRepertoty(BaseDbContext baseDbContext)
{
 _database = baseDbContext.MongoDatabase;
 _collName = typeof(T).GetAttributeValue((TableAttribute m) => m.Name);
 _collName = _collName ?? typeof(T).Name;

}
}
</code></pre>
前面我们已经注册了BaseDbContext,它的主要作用是确定操作的库,那BaseRepertoty就是对具体集合(表)的操作,这里使用泛型,避免重复的CRUD操作 我新建了一个拓展,用于获取实体类上真实集合(表)的名称,如果用户没有指定,则取实体类的类名,做为集合(表)的名称
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-csharp">public static class AttributeExtensions
{
public static TValue GetAttributeValue<TAttribute, TValue>(
 this Type type,
 Func<TAttribute, TValue> valueSelector)
 where TAttribute : Attribute
{
 var att = type.GetCustomAttributes(
 typeof(TAttribute), true
 ).FirstOrDefault() as TAttribute;
 if (att != null)
 {
 return valueSelector(att);
 }
 return default(TValue);
}
}
</code></pre>
<blockquote>
4.创建 UserInfoRepertoty 类
</blockquote>
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-cpp">public class UserInfoRepertoty : BaseRepertoty<UserInfo>
{
public UserInfoRepertoty(BaseDbContext baseDbContext) : base(baseDbContext)
{

}
}
</code></pre>
它的作用是指定操作具体的集合(表),这个类是非必须的,它只是指定了泛型的具体类型,也可以在server层调用的时候指定
<blockquote>
5.创建 UserInfo 实体类
</blockquote>
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-csharp">[Table("UserInfo")]
public class UserInfo
{
/// <summary>
/// 主键
/// </summary>
[BsonId]
public ObjectId Id { get; set; }

/// <summary>
/// 用户名
/// </summary>
public string Name { get; set; }

/// <summary>
/// 年龄
/// </summary>
public int Age { get; set; }

/// <summary>
/// 创建时间
/// </summary>
[BsonDateTimeOptions(Kind = DateTimeKind.Local)]
public DateTime CreateTime { get; set; }

/// <summary>
/// 合作伙伴
/// </summary>
public List<Partner> PartnerList { get; set; }

/// <summary>
/// 其它信息
/// </summary>
public Info Info { get; set; }
}

public class Partner
{
/// <summary>
/// 伙伴名称
/// </summary>
public string Name { get; set; }

/// <summary>
/// 合作状态
/// </summary>
public int? Status { get; set; }
}

public class Info
{
/// <summary>
/// 身份编码
/// </summary>
public string Code { get; set; }

/// <summary>
/// 图片
/// </summary>
public string Pic { get; set; }
}
</code></pre>
mongodb里默认的主键是_id,它会自动生成,类型为ObjectId,强烈推荐使用自动生成,速度快,且能提供获取对应的时间戳的方法
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-python">ObjectId 类似唯一主键，可以很快的去生成和排序，包含 12 bytes，含义是：
前4个字节表示创建 unix 时间戳,格林尼治时间 UTC 时间，比北京时间晚了 8 个小时
接下来的3个字节是机器标识码
紧接的两个字节由进程 id 组成 PID
最后三个字节是随机数
</code></pre>
时间类型要做对应的处理,标记为当前时间
其它常用注解说明
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-mipsasm">BsonId修饰的字段对应BsonDocument中的_id;
BsonDefaultValue(value)用于指定默认值;
BsonIgnore表示不映射，即使BsonDocument中包含该字段也不会赋值给属性;
BsonExtraElements修饰的字段用于存储没有映射到类中的其他属性;
BsonElement可以指定修饰的属性映射到BsonDocument中的哪个字段;
</code></pre>
使用mongodb的一个主要原因,就是它灵活的存储方式,类json,我们就来体验一番,基于这个模型来进行CRUD,我定义的类型如下,基本上能覆盖99%的使用场景
ObjectId (主键) string (字符串) int (数字) object (对象) array (数组)
我们在BaseRepertoty类里,实现CRUD,完整代码如下
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-swift">public class BaseRepertoty<T> where T : class, new()
{
private readonly IMongoDatabase _database;

private readonly string _collName;

public BaseRepertoty(BaseDbContext baseDbContext)
{
 _database = baseDbContext.MongoDatabase;
 _collName = typeof(T).GetAttributeValue((TableAttribute m) => m.Name);
 _collName = _collName ?? typeof(T).Name;

}

#region Add 添加一条数据
/// <summary>
/// 添加一条数据
/// </summary>
/// <param name="t">添加的实体</param>
/// <returns></returns>
public bool Add(T t)
{
 try
 {
 var client = _database.GetCollection<T>(_collName);
 client.InsertOne(t);
 return true;
 }
 catch (Exception ex)
 {
 return false;
 }
}
#endregion

#region AddAsync 异步添加一条数据
/// <summary>
/// 异步添加一条数据
/// </summary>
/// <param name="t">添加的实体</param>
/// <returns></returns>
public async Task<bool> AddAsync(T t)
{
 try
 {
 var client = _database.GetCollection<T>(_collName);
 await client.InsertOneAsync(t);
 return true;
 }
 catch
 {
 return false;
 }
}
#endregion

#region InsertMany 批量插入
/// <summary>
/// 批量插入
/// </summary>
/// <param name="t">实体集合</param>
/// <returns></returns>
public bool InsertMany(List<T> t)
{
 try
 {
 var client = _database.GetCollection<T>(_collName);
 client.InsertMany(t);
 return true;
 }
 catch (Exception ex)
 {
 return false;
 }
}
#endregion

#region InsertManyAsync 异步批量插入
/// <summary>
/// 异步批量插入
/// </summary>
/// <param name="t">实体集合</param>
/// <returns></returns>
public async Task<bool> InsertManyAsync(List<T> t)
{
 try
 {
 var client = _database.GetCollection<T>(_collName);
 await client.InsertManyAsync(t);
 return true;
 }
 catch
 {
 return false;
 }
}
#endregion

#region UpdateOne 修改数据(单条)
/// <summary>
/// 批量修改数据
/// </summary>
/// <param name="update">要修改的字段</param>
/// <param name="filter">修改条件</param>
/// <returns></returns>
public UpdateResult UpdateOne(UpdateDefinition<T> update, FilterDefinition<T> filter)
{
 try
 {
 var client = _database.GetCollection<T>(_collName);
 return client.UpdateOne(filter, update);
 }
 catch (Exception ex)
 {
 throw ex;
 }
}
#endregion

#region UpdateOneAsync 异步批量修改数据
/// <summary>
/// 异步批量修改数据
/// </summary>
/// <param name="update">要修改的字段</param>
/// <param name="filter">修改条件</param>
/// <returns></returns>
public async Task<UpdateResult> UpdateOneAsync(UpdateDefinition<T> update, FilterDefinition<T> filter)
{
 try
 {
 var client = _database.GetCollection<T>(_collName);
 return await client.UpdateOneAsync(filter, update);
 }
 catch (Exception ex)
 {
 throw ex;
 }
}
#endregion

#region UpdateManay 批量修改数据
/// <summary>
/// 批量修改数据
/// </summary>
/// <param name="update">要修改的字段</param>
/// <param name="filter">修改条件</param>
/// <returns></returns>
public UpdateResult UpdateManay(UpdateDefinition<T> update, FilterDefinition<T> filter)
{
 try
 {
 var client = _database.GetCollection<T>(_collName);
 returnclient.UpdateMany(filter, update);
 }
 catch (Exception ex)
 {
 throw ex;
 }
}
#endregion

#region UpdateManayAsync 异步批量修改数据
/// <summary>
/// 异步批量修改数据
/// </summary>
/// <param name="update">要修改的字段</param>
/// <param name="filter">修改条件</param>
/// <returns></returns>
public async Task<UpdateResult> UpdateManayAsync(UpdateDefinition<T> update, FilterDefinition<T> filter)
{
 try
 {
 var client = _database.GetCollection<T>(_collName);
 return await client.UpdateManyAsync(filter, update);
 }
 catch (Exception ex)
 {
 throw ex;
 }
}
#endregion

#region DeleteOne 删除一条数据
/// <summary>
/// 删除多条数据
/// </summary>
/// <param name="filter">删除的条件</param>
/// <returns></returns>
public DeleteResult DeleteOne(FilterDefinition<T> filter)
{
 try
 {
 var client = _database.GetCollection<T>(_collName);
 return client.DeleteOne(filter);
 }
 catch (Exception ex)
 {
 throw ex;
 }

}
#endregion

#region DeleteOneAsync 异步删除一条数据
/// <summary>
/// 异步删除多条数据
/// </summary>
/// <param name="filter">删除的条件</param>
/// <returns></returns>
public async Task<DeleteResult> DeleteOneAsync(FilterDefinition<T> filter)
{
 try
 {
 var client = _database.GetCollection<T>(_collName);
 return await client.DeleteOneAsync(filter);
 }
 catch (Exception ex)
 {
 throw ex;
 }

}
#endregion

#region DeleteMany 删除多条数据
/// <summary>
/// 删除多条数据
/// </summary>
/// <param name="filter">删除的条件</param>
/// <returns></returns>
public DeleteResult DeleteMany(FilterDefinition<T> filter)
{
 try
 {
 var client = _database.GetCollection<T>(_collName);
 return client.DeleteMany(filter);
 }
 catch (Exception ex)
 {
 throw ex;
 }

}
#endregion

#region DeleteManyAsync 异步删除多条数据
/// <summary>
/// 异步删除多条数据
/// </summary>
/// <param name="filter">删除的条件</param>
/// <returns></returns>
public async Task<DeleteResult> DeleteManyAsync(FilterDefinition<T> filter)
{
 try
 {
 var client = _database.GetCollection<T>(_collName);
 return await client.DeleteManyAsync(filter);
 }
 catch (Exception ex)
 {
 throw ex;
 }

}
#endregion

#region FindOne 根据id查询一条数据
/// <summary>
/// 根据id查询一条数据
/// </summary>
/// <param name="id">objectid</param>
/// <param name="field">要查询的字段，不写时查询全部</param>
/// <returns></returns>
public T FindOne(string id, bool isObjectId = true, string[] field = null)
{
 try
 {
 var client = _database.GetCollection<T>(_collName);
 FilterDefinition<T> filter;
 if (isObjectId)
 {
 filter = Builders<T>.Filter.Eq("_id", new ObjectId(id));
 }
 else
 {
 filter = Builders<T>.Filter.Eq("_id", id);
 }
 //不指定查询字段
 if (field == null || field.Length == 0)
 {
 return client.Find(filter).FirstOrDefault<T>();
 }

 //制定查询字段
 var fieldList = new List<ProjectionDefinition<T>>();
 for (int i = 0; i < field.Length; i++)
 {
 fieldList.Add(Builders<T>.Projection.Include(field.ToString()));
 }
 var projection = Builders<T>.Projection.Combine(fieldList);
 fieldList?.Clear();
 return client.Find(filter).Project<T>(projection).FirstOrDefault<T>();
 }
 catch (Exception ex)
 {
 throw ex;
 }
}
#endregion

#region FindOneAsync 异步根据id查询一条数据
/// <summary>
/// 异步根据id查询一条数据
/// </summary>
/// <param name="id">objectid</param>
/// <returns></returns>
public async Task<T> FindOneAsync(string id, bool isObjectId = true, string[] field = null)
{
 try
 {
 var client = _database.GetCollection<T>(_collName);
 FilterDefinition<T> filter;
 if (isObjectId)
 {
 filter = Builders<T>.Filter.Eq("_id", new ObjectId(id));
 }
 else
 {
 filter = Builders<T>.Filter.Eq("_id", id);
 }

 //不指定查询字段
 if (field == null || field.Length == 0)
 {
 return await client.Find(filter).FirstOrDefaultAsync();
 }

 //制定查询字段
 var fieldList = new List<ProjectionDefinition<T>>();
 for (int i = 0; i < field.Length; i++)
 {
 fieldList.Add(Builders<T>.Projection.Include(field.ToString()));
 }
 var projection = Builders<T>.Projection.Combine(fieldList);
 fieldList?.Clear();
 return await client.Find(filter).Project<T>(projection).FirstOrDefaultAsync();
 }
 catch (Exception ex)
 {
 throw ex;
 }
}
#endregion

#region FindList 查询集合
/// <summary>
/// 查询集合
/// </summary>
/// <param name="filter">查询条件</param>
/// <param name="field">要查询的字段,不写时查询全部</param>
/// <param name="sort">要排序的字段</param>
/// <returns></returns>
public List<T> FindList(FilterDefinition<T> filter, string[] field = null, SortDefinition<T> sort = null)
{
 try
 {
 var client = _database.GetCollection<T>(_collName);
 //不指定查询字段
 if (field == null || field.Length == 0)
 {
 if (sort == null) return client.Find(filter).ToList();
 //进行排序
 return client.Find(filter).Sort(sort).ToList();
 }

 //制定查询字段
 var fieldList = new List<ProjectionDefinition<T>>();
 for (int i = 0; i < field.Length; i++)
 {
 fieldList.Add(Builders<T>.Projection.Include(field.ToString()));
 }
 var projection = Builders<T>.Projection.Combine(fieldList);
 fieldList?.Clear();
 if (sort == null) return client.Find(filter).Project<T>(projection).ToList();
 //排序查询
 return client.Find(filter).Sort(sort).Project<T>(projection).ToList();
 }
 catch (Exception ex)
 {
 throw ex;
 }
}
#endregion

#region FindListAsync 异步查询集合
/// <summary>
/// 异步查询集合
/// </summary>
/// <param name="filter">查询条件</param>
/// <param name="field">要查询的字段,不写时查询全部</param>
/// <param name="sort">要排序的字段</param>
/// <returns></returns>
public async Task<List<T>> FindListAsync(FilterDefinition<T> filter, string[] field = null, SortDefinition<T> sort = null)
{
 try
 {
 var client = _database.GetCollection<T>(_collName);
 //不指定查询字段
 if (field == null || field.Length == 0)
 {
 //return await client.Find(new BsonDocument()).ToListAsync();
 if (sort == null) return await client.Find(filter).ToListAsync();
 return await client.Find(filter).Sort(sort).ToListAsync();
 }

 //制定查询字段
 var fieldList = new List<ProjectionDefinition<T>>();
 for (int i = 0; i < field.Length; i++)
 {
 fieldList.Add(Builders<T>.Projection.Include(field.ToString()));
 }
 var projection = Builders<T>.Projection.Combine(fieldList);
 fieldList?.Clear();
 if (sort == null) return await client.Find(filter).Project<T>(projection).ToListAsync();
 //排序查询
 return await client.Find(filter).Sort(sort).Project<T>(projection).ToListAsync();
 }
 catch (Exception ex)
 {
 throw ex;
 }
}
#endregion

#region FindListByPage 分页查询集合
/// <summary>
/// 分页查询集合
/// </summary>
/// <param name="filter">查询条件</param>
/// <param name="pageIndex">当前页</param>
/// <param name="pageSize">页容量</param>
/// <param name="count">总条数</param>
/// <param name="field">要查询的字段,不写时查询全部</param>
/// <param name="sort">要排序的字段</param>
/// <returns></returns>
public List<T> FindListByPage(FilterDefinition<T> filter, int pageIndex, int pageSize, out long count, string[] field = null, SortDefinition<T> sort = null)
{
 try
 {
 var client = _database.GetCollection<T>(_collName);
 count = client.CountDocuments(filter);
 //不指定查询字段
 if (field == null || field.Length == 0)
 {
 if (sort == null) return client.Find(filter).Skip((pageIndex - 1) * pageSize).Limit(pageSize).ToList();
 //进行排序
 return client.Find(filter).Sort(sort).Skip((pageIndex - 1) * pageSize).Limit(pageSize).ToList();
 }

 //制定查询字段
 var fieldList = new List<ProjectionDefinition<T>>();
 for (int i = 0; i < field.Length; i++)
 {
 fieldList.Add(Builders<T>.Projection.Include(field.ToString()));
 }
 var projection = Builders<T>.Projection.Combine(fieldList);
 fieldList?.Clear();

 //不排序
 if (sort == null) return client.Find(filter).Project<T>(projection).Skip((pageIndex - 1) * pageSize).Limit(pageSize).ToList();

 //排序查询
 return client.Find(filter).Sort(sort).Project<T>(projection).Skip((pageIndex - 1) * pageSize).Limit(pageSize).ToList();

 }
 catch (Exception ex)
 {
 throw ex;
 }
}
#endregion

#region FindListByPageAsync 异步分页查询集合
/// <summary>
/// 异步分页查询集合
/// </summary>
/// <param name="filter">查询条件</param>
/// <param name="pageIndex">当前页</param>
/// <param name="pageSize">页容量</param>
/// <param name="field">要查询的字段,不写时查询全部</param>
/// <param name="sort">要排序的字段</param>
/// <returns></returns>
public async Task<List<T>> FindListByPageAsync(FilterDefinition<T> filter, int pageIndex, int pageSize, string[] field = null, SortDefinition<T> sort = null)
{
 try
 {
 var client = _database.GetCollection<T>(_collName);
 //不指定查询字段
 if (field == null || field.Length == 0)
 {
 if (sort == null) return await client.Find(filter).Skip((pageIndex - 1) * pageSize).Limit(pageSize).ToListAsync();
 //进行排序
 return await client.Find(filter).Sort(sort).Skip((pageIndex - 1) * pageSize).Limit(pageSize).ToListAsync();
 }

 //制定查询字段
 var fieldList = new List<ProjectionDefinition<T>>();
 for (int i = 0; i < field.Length; i++)
 {
 fieldList.Add(Builders<T>.Projection.Include(field.ToString()));
 }
 var projection = Builders<T>.Projection.Combine(fieldList);
 fieldList?.Clear();

 //不排序
 if (sort == null) return await client.Find(filter).Project<T>(projection).Skip((pageIndex - 1) * pageSize).Limit(pageSize).ToListAsync();

 //排序查询
 return await client.Find(filter).Sort(sort).Project<T>(projection).Skip((pageIndex - 1) * pageSize).Limit(pageSize).ToListAsync();

 }
 catch (Exception ex)
 {
 throw ex;
 }
}
#endregion

#region Count 根据条件获取总数
/// <summary>
/// 根据条件获取总数
/// </summary>
/// <param name="filter">条件</param>
/// <returns></returns>
public long Count(FilterDefinition<T> filter)
{
 try
 {
 var client = _database.GetCollection<T>(_collName);
 return client.CountDocuments(filter);
 }
 catch (Exception ex)
 {
 throw ex;
 }
}
#endregion

#region CountAsync 异步根据条件获取总数
/// <summary>
/// 异步根据条件获取总数
/// </summary>
/// <param name="filter">条件</param>
/// <returns></returns>
public async Task<long> CountAsync(FilterDefinition<T> filter)
{
 try
 {
 var client = _database.GetCollection<T>(_collName);
 return await client.CountDocumentsAsync(filter);
 }
 catch (Exception ex)
 {
 throw ex;
 }
}
#endregion
}
</code></pre>
<blockquote>
6.创建 UserInfoService 类
</blockquote>
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-csharp">public class UserInfoService
{
private readonly UserInfoRepertoty _userInfoRepertoty;

private readonly FilterDefinitionBuilder<UserInfo> _buildFilter;
public UserInfoService(UserInfoRepertoty userInfoRepertoty)
{
 _userInfoRepertoty = userInfoRepertoty;
 _buildFilter = Builders<UserInfo>.Filter;
}
}
</code></pre>
体验mongodb独特的使用方式,这里挑出两个具有代表性的操作进行讲解,测试数据 <img src="https://img2023.cnblogs.com/blog/772322/202301/772322-20230107164902002-418256653.png" alt="image" class="medium-zoom-image" loading="lazy">
分页查询集合(表)
<ul>
<li>1.动态条件查询</li>
<li>2.查询文档指定字段</li>
<li>3.排序</li>
<li>4.分页</li>

</ul>
定义查询操作
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-xml">FilterDefinition<UserInfo> filter = _buildFilter.Empty;
</code></pre>
查询条件由查询条件构造器构建,这个地方网上很多示例写的有bug,当查询所有集合(表)数据的时候,filter = null 在转换的时候会抛出异常
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-perl">//创建查询条件构造器
FilterDefinitionBuilder<UserInfo> _buildFilter = Builders<UserInfo>.Filter;
//定义查询条件
FilterDefinition<UserInfo> filter = null;
if(!string.IsNullOrEmpty(request.Name)) filter = _buildFilter.Eq(m => m.Name, request.Name);
</code></pre>
这里有很多种类型的构造器,对应不同的操作
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-swift">//排序操作
SortDefinition<UserInfo> sort
//排序构造器
Builders<UserInfo>.Sort

修改操作
UpdateDefinition<UserInfo> update
//修改构造器
Builders<UserInfo>.Update

</code></pre>
完整的查询示例,比较麻烦的地方,是针对数组的条件查询,如果嵌套的层数比较多,查询也是同理的套娃查询
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-csharp">public class GetUserListRequest
{
/// <summary>
/// 名称
/// </summary>
public string Name { get; set; }

/// <summary>
/// 年龄
/// </summary>
public int? Age { get; set; }

/// <summary>
/// 创建时间
/// </summary>
public DateTime CreateTime { get; set; }

/// <summary>
/// 合作伙伴
/// </summary>
public Partner PartnerList { get; set; }

/// <summary>
/// 信息
/// </summary>
public Info Info { get; set; }
}

public async Task<List<UserInfo>> GetUserPageList(GetUserListRequest request)
{
if (request == null) return new List<UserInfo>();
FilterDefinition<UserInfo> filter = _buildFilter.Empty;

SortDefinition<UserInfo> sort = Builders<UserInfo>.Sort.Ascending(m => m.Age);

if (!string.IsNullOrEmpty(request.Name))
{
 filter = _buildFilter.Eq(m => m.Name, request.Name);
}
if (request.Age.HasValue)
{
 filter = _buildFilter.Eq(m => m.Age, request.Age);
}
if (request.PartnerList != null)
{
 if (request.PartnerList.Status.HasValue)
 {
 filter = _buildFilter.ElemMatch("PartnerList", Builders<Partner>.Filter.Eq(m => m.Status, request.PartnerList.Status));
 }
}
if (request.Info != null)
{
 if (!string.IsNullOrEmpty(request.Info.Code))
 {
 filter = _buildFilter.Eq(m => m.Info.Code, request.Info.Code);
 }
}
var list = await _userInfoRepertoty.FindListByPageAsync(filter,1,3, new string[] { "Name","Age", "CreateTime" }, sort);
return list;
}
</code></pre>
<blockquote>
动态条件查询(查询全部)
</blockquote>
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-csharp">var list = await _userInfoRepertoty.FindListByPageAsync(filter, 1, 30);
</code></pre>
<img src="https://img2023.cnblogs.com/blog/772322/202301/772322-20230107165330867-1282156814.png" alt="image" class="medium-zoom-image" loading="lazy">
<blockquote>
条件查询,排序,分页,查询指定字段
</blockquote>
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-csharp">var list = await _userInfoRepertoty.FindListByPageAsync(filter,1,3, new string[] { "Name","Age", "CreateTime" }, sort);
</code></pre>
<img src="https://img2023.cnblogs.com/blog/772322/202301/772322-20230107170055863-885107849.png" alt="image" class="medium-zoom-image" loading="lazy"> 除了使用对象模型进行操作,也可以直接使用mongodb原生的BsonDocument进行操作
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-mipsasm">var buildFilter = Builders<BsonDocument>.Filter;
FilterDefinition<BsonDocument> filter = _buildFilter.Empty;;
BsonDocument bson = new BsonDocument
{
{ "Age",20},
{"Info.Status",3 }
};

foreach (var bs in bson)
{
filter = _buildFilter.Eq(bs.Name, bs.Value);

}
var sort = Builders<BsonDocument>.Sort;
var list = await collection.Find(filter).Sort(sort.Descending("age")).ToListAsync();
</code></pre>
修改集合(表)的数据
<ul>
<li>1.修改满足条件的文档</li>
<li>2.修改文档的部分字段</li>
</ul>
<pre class="highlighter-hljs"><code class="highlighter-hljs hljs language-typescript">public async Task UpdateUserInfo()
{
//修改条件
FilterDefinition<UserInfo> filter = _buildFilter.Empty;
filter = _buildFilter.Eq(m => m.Name, "tibos");
filter = _buildFilter.ElemMatch(list => list.PartnerList, child => child.Status == 1);

//修改字段
var update = Builders<UserInfo>.Update.Set("Age",100).Set("PartnerList.$.Name", "ppp").Set("PartnerList.$.Status", "");
await _userInfoRepertoty.UpdateManayAsync(update, filter);
}</code></pre> 
来源：https://www.cnblogs.com/wl-blog/p/17073022.html

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