该投票系统实现的功能较为简单，适合初学者借鉴。
数据库表只有三张：用户表、投票信息表和投票选项表，采用的是SQLServer数据库，后端采用ASP .NET框架（C#），前端采用Angular，UI组件采用的是NG-ZORRO。功能较简单，有用户登录与注册、查看投票列表，进行投票，发起投票，查看投票结果等功能。
第一步：在Visual Studio 创建一个新的项目
第二步：创建数据实体类的文件夹Models
User.cs
using ponentModel.DataAnnotations.Schema;namespace Vote_Api.Models{[Table("UserInfo")]public class User{public string UserId {get; set; }public string Passwd {get; set; }public string Tel {get; set; }public int Age {get; set; }public string Sex {get; set; }}}
VoteInfo.cs
using System;using ponentModel.DataAnnotations.Schema;namespace Vote_Api.Models{[Table("VoteInfo")]public class VoteInfo{public int ID {get; set; }public string Vote_Title {get; set; }public int? Vote_Sum {get; set; }public DateTime Start_Time {get; set; }public DateTime End_Time {get; set; }public bool Vote_Type {get; set; }public string UserID {get; set; }}}
VoteOption.cs
using ponentModel.DataAnnotations.Schema;namespace Vote_Api.Models{[Table("VoteOption")]public class VoteOption{public int ID {get; set; }public string Vote_Item {get; set; }public int Vote_Num {get; set; }public int Vote_ID {get; set; }}}
第三步：在appsettings.json添加配置数据库连接字符串
"ConnectionStrings": {"sqlserverConn": "Server=地址;Database=数据库名;user id=用户名;password=密码;"}
第四步：在Models中创建一个类继承DbContext
using Microsoft.EntityFrameworkCore;namespace Vote_Api.Models{public class VoteContext :DbContext{public VoteContext(DbContextOptions<VoteContext> options) : base(options) {}public DbSet<User> User_Info {get; set; }public DbSet<VoteInfo> Vote_Info {get; set; }public DbSet<VoteOption> Vote_Option {get; set; }}}
还要在Startup.cs的ConfigureService方法中添加注入
public void ConfigureServices(IServiceCollection services){services.AddControllers();services.AddDbContext<VoteContext>(options =>options.UseSqlServer(Configuration.GetConnectionString("sqlserverConn"))); //"sqlserverConn"是之前在appsettings.json中配置的连接字符串}
第五步：编写业务逻辑
IVoteInfoService.cs
using System;using Vote_Api.Models;namespace Vote_Api.Service.IService{public interface IVoteInfoService{int AddVote(VoteInfo vote); //发起投票bool AddVoteOption(VoteOption voteop); //添加投票选项string getAllVotes(); //获取所有投票列表string getVoteById(int id); //查看某个投票详情string getVoteOptionById(int id); //获取某个投票选项bool doVote(int id); //进行投票string getMyVotes(string user_id); //获取某个用户发起的投票列表}}
接口实现类VoteInfoService.cs
using Microsoft.EntityFrameworkCore;using Newtonsoft.Json;using System;using System.Collections.Generic;using System.Linq;using Vote_Api.Models;using Vote_Api.Service.IService;namespace Vote_Api.Service.ServiceImpl{public class VoteInfoService : IVoteInfoService{private readonly VoteContext _context;public VoteInfoService(VoteContext context){_context = context;//注入数据库上下文}public int AddVote(VoteInfo vote){_context.Vote_Info.Add(vote);int res = _context.SaveChanges();if(res == 1){return vote.ID; //添加投票信息成功后返回id}else{return 0;}}public bool AddVoteOption(VoteOption voteop){_context.Vote_Option.Add(voteop);int res = _context.SaveChanges();if(res == 1){return true;}else{return false;}}public string getAllVotes(){List<VoteInfo> votes = _context.Vote_Info.ToList();_context.SaveChanges();return JsonConvert.SerializeObject(votes); //序列化}public string getVoteById(int id){VoteInfo vote = _context.Vote_Info.Find(id);_context.SaveChanges();return JsonConvert.SerializeObject(vote);}public string getVoteOptionById(int id){string sql = "select * from VoteOption where Vote_ID = "+id;var voteOption = _context.Vote_Option.FromSqlRaw(sql); //采用原生的Sql语句_context.SaveChanges();return JsonConvert.SerializeObject(voteOption);}public bool doVote(int id){VoteOption vop = _context.Vote_Option.Find(id);vop.Vote_Num += 1; VoteInfo v =_context.Vote_Info.Find(vop.Vote_ID);v.Vote_Sum += 1;int res = _context.SaveChanges();Console.WriteLine(res);if (res == 2 ){return true;}else{return false;}}public string getMyVotes(string user_id){string sql = "select * from VoteInfo where UserID = '" + user_id+"'";var myvote = _context.Vote_Info.FromSqlRaw(sql);_context.SaveChanges();return JsonConvert.SerializeObject(myvote);}}}
第六步：同样需要在在Startup.cs中添加注入服务
public void ConfigureServices(IServiceCollection services){services.AddControllers();services.AddDbContext<VoteContext>(options =>options.UseSqlServer(Configuration.GetConnectionString("sqlserverConn")));services.AddTransient<IVoteInfoService, VoteInfoService>();//注入刚刚创建的接口和实现类}
第七步：创建Controller，编写接口
using Microsoft.AspNetCore.Authorization;using Microsoft.AspNetCore.Mvc;using Vote_Api.Models;using Vote_Api.Service.IService;namespace Vote_Api.Controllers{[Route("api/vote")][ApiController]public class VoteController : Controller{private readonly IVoteInfoService _service;public VoteController(IVoteInfoService service){_service = service;}[HttpGet("getAllVotes")]public string getAllVotes(){return _service.getAllVotes();}[HttpGet("getVoteById")]public string getVoteById(int vote_id){return _service.getVoteById(vote_id);}[HttpGet("getVoteOptionById")]public string getVoteOptionById(int vote_option_id){return _service.getVoteOptionById(vote_option_id);}[HttpGet("doVote")]public bool doVote(int vote_option_id){return _service.doVote(vote_option_id);}[HttpGet("getMyVotes")]public string getMyVotes(string user_id){return _service.getMyVotes(user_id);}[HttpPost("AddVote")]public int AddVote(VoteInfo vote){return _service.AddVote(vote);}[HttpPost("AddVoteOption")]public bool AddVoteOption(VoteOption voteop){return _service.AddVoteOption(voteop);}}}
第八步：postman测试api
到此投票模块的功能api已经简单完成，下一篇会讲登录模块的api实现。写得很简单，适合初学者。如有不足，评论区见。
