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C# 尚未为此DbContext配置任何数据库提供程序。尝试更新数据库时出错_C#_Sql Server_Asp.net Core Mvc_Entity Framework Core - Fatal编程技术网

C# 尚未为此DbContext配置任何数据库提供程序。尝试更新数据库时出错

C# 尚未为此DbContext配置任何数据库提供程序。尝试更新数据库时出错,c#,sql-server,asp.net-core-mvc,entity-framework-core,C#,Sql Server,Asp.net Core Mvc,Entity Framework Core,当我更新数据库时,出现以下错误: 尚未为此DbContext配置任何数据库提供程序。可以通过重写DbContext.OnConfigurang方法或在应用程序服务提供程序上使用AddDbContext来配置提供程序。如果使用AddDbContext,那么还要确保DbContext类型在其构造函数中接受DbContextOptions对象,并将其传递给DbContext的基本构造函数 我希望有人能帮我解决我的问题 这是我的上下文类和启动类 DataBaseContext.cs using Micr

当我更新数据库时,出现以下错误:

尚未为此DbContext配置任何数据库提供程序。可以通过重写DbContext.OnConfigurang方法或在应用程序服务提供程序上使用AddDbContext来配置提供程序。如果使用AddDbContext,那么还要确保DbContext类型在其构造函数中接受DbContextOptions对象,并将其传递给DbContext的基本构造函数

我希望有人能帮我解决我的问题

这是我的上下文类和启动类

DataBaseContext.cs

using Microsoft.EntityFrameworkCore;
using MovieExampleAppDotNetCore.Models;


namespace MovieExampleApp.Persistention
{
  public class DatabaseContext : DbContext
  {
    public DatabaseContext(DbContextOptions<DatabaseContext> context) : base(context)
    {
        //Database.Initialize(true);
    }

    public DatabaseContext()
    {
    }

    public DatabaseContext(DbContextOptions options) : base(options)
    {
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);
    }

    public DbSet<Movie> Movies { get; set; }
    public DbSet<Customer> Customers { get; set; }
  }
}
使用Microsoft.AspNetCore.Builder;
使用Microsoft.AspNetCore.Hosting;
使用Microsoft.AspNetCore.Mvc;
使用Microsoft.AspNetCore.Mvc.Formatters;
使用Microsoft.EntityFrameworkCore;
使用Microsoft.Extensions.Configuration;
使用Microsoft.Extensions.DependencyInjection;
使用Microsoft.Extensions.Hosting;
使用Microsoft.Extensions.Options;
使用Microsoft.EntityFrameworkCore.SqlServer;
使用System.Linq;
使用MovieExampleApp.persistension;
使用Microsoft.AspNetCore.Http;
使用Microsoft.AspNetCore.Mvc.Infrastructure;
命名空间MovieExampleAppDotNetCore
{
公营创业
{
公共启动(IConfiguration配置)
{
配置=配置;
}
公共IConfiguration配置{get;}
//此方法由运行时调用。请使用此方法将服务添加到容器中。
public void配置服务(IServiceCollection服务)
{
services.AddMvc();
services.AddDbContext(
options=>options.UseSqlServer(Configuration.GetConnectionString(“DefaultConnection”));
services.AddControllersWithViews().AddNewtonsoftJson();
services.addcontrollerswithview(选项=>
{
Insert(0,GetJsonPatchInputFormatter());
});
}
私有静态NewtonsoftJsonPatchInputFormatter GetJsonPatchInputFormatter()
{
var builder=newservicecolection()
.AddLogging()
.AddMvc()
.AddNewtonsoftJson()
.Services.BuildServiceProvider();
返回生成器
.GetRequiredService()
价值
.输入格式化程序
第()类
.First();
}
//此方法由运行时调用。请使用此方法配置HTTP请求管道。
public void配置(IApplicationBuilder应用程序、IWebHostEnvironment环境)
{
if(env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
其他的
{
app.UseExceptionHandler(“/Home/Error”);
//默认的HSTS值为30天。您可能希望在生产场景中更改此值,请参阅https://aka.ms/aspnetcore-hsts.
app.UseHsts();
}
app.UseHttpsRedirection();
app.UseStaticFiles();
app.UseRouting();
app.UseAuthorization();
app.UseEndpoints(端点=>
{
endpoints.MapControllerRoute(
名称:“默认”,
模式:“{controller=Home}/{action=Index}/{id?}”);
});
}
}
}

您检查过这个吗?DefaultConnectionIt是我的connectionstring。为什么在DbContext中需要3个构造函数?具有通用DbContextOptions的选项就足够了。尝试删除另外两个当我删除另外两个时,它会给我一个错误。什么错误?连接字符串是什么样子的?错误抱怨连接字符串中缺少信息
Startup.cs
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Formatters;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Options;
using Microsoft.EntityFrameworkCore.SqlServer;
using System.Linq;
using MovieExampleApp.Persistention;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc.Infrastructure;


namespace MovieExampleAppDotNetCore
{
    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.AddMvc();
            services.AddDbContext<DatabaseContext>(
            options => options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));



            services.AddControllersWithViews().AddNewtonsoftJson();

            services.AddControllersWithViews(options =>
            {
                options.InputFormatters.Insert(0, GetJsonPatchInputFormatter());
            });

        }

        private static NewtonsoftJsonPatchInputFormatter GetJsonPatchInputFormatter()
        {
            var builder = new ServiceCollection()
                .AddLogging()
                .AddMvc()
                .AddNewtonsoftJson()
                .Services.BuildServiceProvider();

            return builder
                .GetRequiredService<IOptions<MvcOptions>>()
                .Value
                .InputFormatters
                .OfType<NewtonsoftJsonPatchInputFormatter>()
                .First();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Home/Error");
                // 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.UseStaticFiles();

            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllerRoute(
                    name: "default",
                    pattern: "{controller=Home}/{action=Index}/{id?}");
            });
        }
    }
}