ASP.NET 初次连接数据库Mysql及初始化操作

首先按照MVC模式：

在Model新建Table.cs，对应数据库的Table表；
在View新建Table文件夹新建Index页面；
在Controller控制器新建针对Table的TableController；

安装一些常用的扩展包

Id                                  Versions                                 ProjectName                                                                                                                                                         
--                                  --------                                 -----------                                                                                                                                                         
Microsoft.AspNetCore.Diagnostics    {2.2.0}                                  RmWebApp                                                                                                                                                            
Microsoft.AspNetCore.Mvc.Razor.R... {5.0.9}                                  RmWebApp                                                                                                                                                            
Microsoft.EntityFrameworkCore.Sq... {5.0.9}                                  RmWebApp                                                                                                                                                            
Newtonsoft.Json                     {13.0.1}                                 RmWebApp                                                                                                                                                            
Microsoft.AspNetCore.Identity.En... {5.0.9}                                  RmWebApp                                                                                                                                                            
Microsoft.VisualStudio.Web.CodeG... {5.0.2}                                  RmWebApp                                                                                                                                                            
Microsoft.EntityFrameworkCore.Tools {5.0.9}                                  RmWebApp                                                                                                                                                            
MySql.Data                          {8.0.26}                                 RmWebApp                                                                                                                                                            
Pomelo.EntityFrameworkCore.MySql    {5.0.1}                                  RmWebApp                                                                                                                                                            
Microsoft.VisualStudio.Web.CodeG... {5.0.2}                                  RmWebApp                                                                                                                                                            
Microsoft.AspNetCore.Identity.UI    {5.0.9}                                  RmWebApp

在Models中编辑Table.cs，定义Table这个表的字段：

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Threading.Tasks;

namespace RmWebApp.Models
{
    public class Table
    {
        //主键
        [Key]
        public int Fid { get; set; }
        //表名
        public String TableName { get; set; }
        //注释
        public String Caption { get; set; }
    }
}

在models中新建ApplicationDbContext.cs文件，编写上下文，继承自DbContext

using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Text;
using RmWebApp.Models;

namespace RmWebApp.Models
{
    public class ApplicationDbContext : DbContext
    {
        public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
    : base(options)
        {
        }
        public DbSet<Meta> Meta { get; set; }
        public DbSet<Table> Table { get; set; }
    }
}

在根目录新建web.config配置文件

<?xml version="1.0" encoding="utf-8"?>
<configuration>

  <!-- To customize the asp.net core module uncomment and edit the following section. 
  For more info see https://go.microsoft.com/fwlink/?linkid=838655 -->
  <!--
  <system.webServer>
    <handlers>
      <remove name="aspNetCore"/>
      <add name="aspNetCore" path="*" verb="*" modules="AspNetCoreModule" resourceType="Unspecified"/>
    </handlers>
    <aspNetCore processPath="%LAUNCHER_PATH%" arguments="%LAUNCHER_ARGS%" stdoutLogEnabled="false" stdoutLogFile=".\logs\stdout" />
  </system.webServer>
  -->
  <connectionStrings>
    <add name="ApplicationDbContext" connectionString="Data Source=localhost;port=3306; Initial Catalog=rmscada;uid=root; pwd=root" providerName="MySql.Data.MySqlClient" />
  </connectionStrings>
</configuration>

说明：“ApplicationDbContext”是上下文名称，rmscada数据库名称，pwd是密码，酌情修改

修改Startup.cs启动文件，编辑 ConfigureServices部分

public void ConfigureServices(IServiceCollection services)
{
    services.AddControllersWithViews();
    services.AddDbContext<ApplicationDbContext>(options 
        =>options.UseMySql(Configuration.GetConnectionString("DefaultConnection"),
        ServerVersion.AutoDetect(Configuration.GetConnectionString("DefaultConnection"))));

    services.AddDefaultIdentity<IdentityUser>(options => options.SignIn.RequireConfirmedAccount = true)
        .AddEntityFrameworkStores<ApplicationDbContext>();
    services.AddControllersWithViews();
    services.AddRazorPages().AddRazorRuntimeCompilation();

}

修改appsettings.json数据库连接文件

{
  "ConnectionStrings": {
    "DefaultConnection": "Server=localhost;Database=数据库名称;user=root;password=数据库密码"
  },
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  },
  "AllowedHosts": "*"
}