C# MongoDB 查询,分组,聚合,排序,条件,分页

先下载个C#的驱动。MongoDB提供各种主流与非主流预言的开发驱动。

C# Driver 下载地址：这里

CSharp Driver Tutorial：这里

下载文件安装或者解压缩包

如果您是安装，请到安装位置寻找，如果是ZIP压缩包，解压缩包得到如下两个文件：

1. MongoDB.Bson.dll              ：序列化、Json相关
2. MongoDB.Driver.dll             ：我们的驱动

没了，只有这两个文件是我们的最爱。

有帮助点推荐

using MongoDB.Driver;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using MySteel.Common.Helper;
using MongoDB.Driver.Builders;
using MongoDB.Bson.Serialization.Attributes;
using MongoDB.Bson;

namespace Test.MongoDB
{
    class Program
    {
        /// <summary>
        /// 数据库连接
        /// </summary>
        private const string conn = "mongodb://192.168.200.184:27017";
        /// <summary>
        /// 指定的数据库
        /// </summary>
        private const string dbName = "mlog";
        /// <summary>
        /// 指定的表
        /// </summary>
        private const string tbName = "log_table";
        //创建数据连接
        private static MongoServer server = MongoServer.Create(conn);
        //获取指定数据库
        private static MongoDatabase db = server.GetDatabase(dbName);

        static void Main(string[] args)
        {
            //for (var index = 0; index < 2; index++)
            //{
            //    Student stu = new Student();
            //    stu.Name = "name" + index;
            //    stu.Age = index;
            //    stu.CreateDateTime = DateTime.Now.ToMillisecond();
            //    stu.Ques = new List<Ques>();
            //    stu.Ques.Add(new Ques() { Name = "qname" + index });
            //    Add(stu);
            //}
            Console.WriteLine("获取学生数据列表");
            var list = GetStudentList();
            foreach (var item in list)
            {
                Console.WriteLine(item.Name + " " + item.Age);
            }
            Console.WriteLine("获取学生姓名分组和数量");
            Dictionary<string, int> group = GetStudentGroup();
            foreach (var item in group)
            {
                Console.WriteLine(item.Key + " " + item.Value);
            }
            Console.Read();
        }
        /// <summary>
        /// 添加
        /// </summary>
        /// <param name="text">内容</param>
        /// <param name="articleId">文章ID</param>
        /// <param name="channelId">频道ID</param>
        /// <returns></returns>
        public static void Add(Student t)
        {
            //获取表
            MongoCollection col = db.GetCollection(tbName);
            //插入
            col.Insert(t);

        }
        public static List<Student> GetStudentList()
        {
            //创建数据连接
            MongoServer server = MongoServer.Create(conn);
            //获取指定数据库
            MongoDatabase db = server.GetDatabase(dbName);
            //获取表
            MongoCollection<Student> col = db.GetCollection<Student>(tbName);
            //条件查询              
            var query = Query.And(Query.LTE("Age", 5));  
            MongoCursor<Student> mongoCursor = col.FindAs<Student>(query);
            //总数
            Console.WriteLine(mongoCursor.Count());
            mongoCursor = col.FindAs<Student>(query);
            //排序
            mongoCursor.SetSortOrder(SortBy.Descending("Age"));
            //分页
            mongoCursor.SetSkip(2);
            mongoCursor.SetLimit(2);
            List<Student> result = mongoCursor.ToList(); 
            return result;
        }
        public static Dictionary<string, int> GetStudentGroup()
        {
            Dictionary<string, int> result = new Dictionary<string, int>();
            result["num"] = 0;
            //创建数据连接
            MongoServer server = MongoServer.Create(conn);
            //获取指定数据库
            MongoDatabase db = server.GetDatabase(dbName);
            //获取表
            MongoCollection<Student> col = db.GetCollection<Student>(tbName);
            GroupByBuilder groupbyBuilder = new GroupByBuilder(new string[] { "Name" });
            var query = Query.And(Query.LTE("Age", 5));
            var result_R = col.Group(query, groupbyBuilder, BsonDocument.Create(result), BsonJavaScript.Create("function(doc,prev){prev.num++;}"),
                                               BsonJavaScript.Create("function(doc){ doc.count=doc.num;delete doc.num; }")).ToList();
            if (result_R.Count != 0)
            {
                result = new Dictionary<string, int>();
                for (int i = 1; i < result_R.Count; i++)
                {
                    result.Add(result_R[i]["Name"].ToString(), Convert.ToInt32(result_R[i]["count"]));

                }
            }
            return result;
        }
    }
    [BsonIgnoreExtraElements]
    public class Student
    {
        public string Name { get; set; }
        public int Age { get; set; }
        public List<Ques> Ques { get; set; }
        public long CreateDateTime { get; set; }
    }
    [BsonIgnoreExtraElements]
    public class Ques
    {
        public string Name { get; set; }
    }
}