首先下载安装 MongoDB
https://www.mongodb.com/download-center/community

新建数据库

创建WEB API项目

using MongoDB.Bson;
using MongoDB.Bson.Serialization.Attributes;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace BooksApi.Models
{
    public class Book
    {
        [BsonId]//指定主键
        [BsonRepresentation(BsonType.ObjectId)]
        public string Id { get; set; }

        [BsonElement("Name")]
        public string BookName { get; set; }

        [BsonElement("Price")]
        public decimal Price { get; set; }

        [BsonElement("Category")]
        public string Category { get; set; }

        [BsonElement("Author")]
        public string Author { get; set; }
    }
}

创建Services文件夹添加BookService服务类

using BooksApi.Models;
using Microsoft.Extensions.Configuration;
using MongoDB.Driver;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace BooksApi.Services
{
    public class BookService
    {
        private readonly IMongoCollection<Book> _books;
        public BookService(IConfiguration configuration)
        {
            //获取操作实例 进行构造注入
            var client = new MongoClient(configuration.GetConnectionString("MongoDBConnString"));
            var database = client.GetDatabase("DB");
            _books = database.GetCollection<Book>("Books");
        }
        public async Task<Book> Create(Book book)
        {
            await _books.InsertOneAsync(book);
            return book;
        }
        public async Task<List<Book>> Get()
        {
           var result= await _books.FindAsync(book=> true);
           return result.ToList();
        }
        public async Task Update(string id, Book bookIn)
        {
          await  _books.ReplaceOneAsync(book => book.Id == id, bookIn);
        }

        public async Task Remove(Book bookIn)
        {
           await _books.DeleteOneAsync(book => book.Id == bookIn.Id);
        }

        public async Task Remove(string id)
        {
           await _books.DeleteOneAsync(book => book.Id == id);
        }
    }
}

appsettings.json中配置DB连接字符串

{
  "ConnectionStrings": {
    "MongoDBConnString": "mongodb://localhost:27017"
  },
  "Logging": {
    "LogLevel": {
      "Default": "Warning"
    }
  },
  "AllowedHosts": "*"
}

Startup中配置服务注册，否则不能进行依赖注入消费。

   public void ConfigureServices(IServiceCollection services)
        {
            services.AddScoped<BookService>();
            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
        }

添加Book控制器

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using BooksApi.Models;
using BooksApi.Services;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;

namespace BooksApi.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class BooksController : ControllerBase
    {
        private readonly BookService _bookService;
        public BooksController(BookService bookService)
        {
            _bookService = bookService;
        }
        public async Task<List<Book>> Get()
        {
            return await _bookService.Get();
        }
        public async Task<Book> Create(Book book)
        {
            return await _bookService.Create(book);
        }
        //其他方法同理，不一一进行实现。
    }
}

安装Swagger进行测试。这里我使用以下Swagger包
https://github.com/RicoSuter/NSwag
具体使用方法文档已经有文字和视频讲解，此处不做说明。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using BooksApi.Services;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.HttpsPolicy;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;

namespace BooksApi
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddScoped<BookService>();
            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
           services.AddSwaggerDocument();--添加SwaggerUI
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
                app.UseHsts();
            }

            app.UseHttpsRedirection();
            app.UseMvc();
            app.UseSwagger();
            app.UseSwaggerUi3();
        }
    }
}

运行测试