EF Core + MySQL 基本增删改查

Core ,MySQL · 浏览次数 : 541

小编点评

**UsersController.cs** ```csharp [ApiController] [Route("api/[controller]")] public class UsersController : Controller { private readonly MyDataBaseContext_mian _dbmain; private readonly MyDataBaseContext_from _dbfrom; public UsersController(MyDataBaseContext_mian dbmain, MyDataBaseContext_from dbfrom) { _dbmain = dbmain; _dbfrom = dbfrom; } [HttpGet] // GET: UsersController public IEnumerable Index() { return _dbfrom.Users.ToList(); } [HttpGet("{id}")] // GET: UsersController/Details/5 public async Task Details(int? id) { return CreatedAtAction(nameof(Index), await _dbfrom.Users.AsNoTracking().FirstOrDefaultAsync(m => m.UserId == id)); } // POST: UsersController/Create [HttpPost] public async Task Create(User user) { _dbmain.Users.Add(user); await _dbmain.SaveChangesAsync(); return CreatedAtAction(nameof(Index), new { id = user.UserId }, user); } // POST: UsersController/Edit/5 [HttpPut(\"{id}\")] public async Task Edit(int? id, [FromBody] User user) { _dbmain.Set().Update(user); return await _dbmain.SaveChangesAsync() > 0; } // POST: UsersController/Delete/5 [HttpDelete(\"{id}\")] public async Task Delete(int id) { User user = new User(); user = await _dbmain.Users.FindAsync(id); if (user == null) { return RedirectToAction(nameof(Index)); } try { _dbmain.Users.Remove(user); await _dbmain.SaveChangesAsync(); return RedirectToAction(nameof(Index)); } catch (DbUpdateException /* ex */) { //Log the error (uncomment ex variable name and write a log.) return RedirectToAction(nameof(Index), new { id = id, saveChangesError = true }); } } } ``` **其他说明：** * `MyDataBaseContext_mian` 和 `MyDataBaseContext_from` 变量是用于数据库连接的上下文对象。 * `_dbmain` 用于执行数据库操作的上下文。 * `_dbfrom` 用于读取数据库操作的上下文。 * `User` 是一个模型类，表示数据库中的 `User` 表的实体。

正文

前言

基于EF Core + MySQL的基本增删改查，示例是基于.NET6 + EF Core + MySQL 创建实体和数据库、EFCore 数据迁移项目基础上的内容增加。同时也是对基于Canal实现MySQL 8.0 数据库数据同步项目的验证。

创建控制器

Controllers---->添加---->控制器，选择api---->包含读写操作的API控制器。

依赖注入

将上下文类注入到UsersController中，ASP.NET Core 支持依赖关系注入 (DI) 软件设计模式，这是一种在类及其依赖关系之间实现控制反转 (IoC) 的技术。有三种具体实现方式，我们这里用到的是构造函数注入，关于这块的内容，以后我们也可以专门出一期。直接上代码。

		private readonly MyDataBaseContext_mian _dbmain;
        private readonly MyDataBaseContext_from _dbfrom;
        public UsersController(MyDataBaseContext_mian dbmain, MyDataBaseContext_from dbfrom)
        {
            _dbmain = dbmain;
            _dbfrom = dbfrom;
        }

CRUD基本代码

一下内容是UsersController的完整内容

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using test.Models;
using test.MyDataBaseContext;

namespace test.Controllers
{
    [ApiController]
    [Route("api/[controller]")]
    public class UsersController : Controller
    {
        private readonly MyDataBaseContext_mian _dbmain;
        private readonly MyDataBaseContext_from _dbfrom;
        public UsersController(MyDataBaseContext_mian dbmain, MyDataBaseContext_from dbfrom)
        {
            _dbmain = dbmain;
            _dbfrom = dbfrom;
        }
        [HttpGet]
        // GET: UsersController
        public IEnumerable<User> Index()
        {
            return _dbfrom.Users.ToList();
        }

        [HttpGet("{id}")]
        // GET: UsersController/Details/5
        public async Task<IActionResult> Details(int? id)
        {
            return CreatedAtAction(nameof(Index), await _dbfrom.Users.AsNoTracking().FirstOrDefaultAsync(m => m.UserId == id));
        }

        // POST: UsersController/Create
        [HttpPost]
        public async Task<IActionResult> Create(User user)
        {
            _dbmain.Users.Add(user);
            await _dbmain.SaveChangesAsync();
            return CreatedAtAction(nameof(Index), new { id = user.UserId }, user);
        }

       // POST: UsersController/Edit/5
        [HttpPut("{id}")]
        public async Task<bool> Edit(int? id, [FromBody] User user)
        {
            _dbmain.Set<User>().Update(user);
            return await _dbmain.SaveChangesAsync() > 0;
        }

        // POST: UsersController/Delete/5
        [HttpDelete("{id}")]
        public async Task<IActionResult> Delete(int id)
        {

            User user = new User();

            user = await _dbmain.Users.FindAsync(id);
            if (user == null)
            {
                return RedirectToAction(nameof(Index));
            }
            try
            {
                _dbmain.Users.Remove(user);
                await _dbmain.SaveChangesAsync();
                return RedirectToAction(nameof(Index));
            }
            catch (DbUpdateException /* ex */)
            {
                //Log the error (uncomment ex variable name and write a log.)
                return RedirectToAction(nameof(Index), new { id = id, saveChangesError = true });
            }

        }
    }
}

注：我对方法进行的改造，采用官网提供的新写法，有兴趣的小伙伴可以看看官网。