没有给出与所需形式参数“选项”相对应的参数
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【中文标题】没有给出与所需形式参数“选项”相对应的参数【英文标题】:There is no argument given that corresponds to the required formal parameter 'options' 【发布时间】:2017-09-23 21:08:47 【问题描述】:我正在 .Net Core 中开发我的第一个应用程序。
由于某种原因,我收到此构建错误:
错误 CS7036 没有给出与 'LakeViewContext.LakeViewContext(DbContextOptions
)' LakeView 所需的形参 'options' 对应的参数
我无法通过 Google 搜索或 MS 文档找到解决方案。
我的上下文类:
using LakeView.Models;
using Microsoft.EntityFrameworkCore;
namespace LakeView
public class LakeViewContext : DbContext
public LakeViewContext(DbContextOptions<LakeViewContext> options) : base(options)
public DbSet<htmlElement> HTMLElements get; set;
public DbSet<CustomizedElement> CustomizedElements get; set;
public DbSet<TemplateFileType> TemplateFileTypes get; set;
public DbSet<StyleFile> StyleFiles get; set;
public DbSet<Template> Templates get; set;
public DbSet<Course> Courses get; set;
public DbSet<Page> Pages get; set;
public DbSet<HTML> HTMLs get; set;
public DbSet<Comment> Comments get; set;
protected override void OnModelCreating(ModelBuilder modelBuilder)
modelBuilder.Entity<CustomizedElementTemplate>()
.HasKey(s => new s.CustomizedElementId, s.TemplateId );
base.OnModelCreating(modelBuilder);
控制器类:
using LakeView.Models;
using LakeView.Models.ViewModels;
using Microsoft.AspNetCore.Mvc;
using System.Collections.Generic;
using System.Linq;
namespace LakeView.Controllers
public class CoursesController : Controller
private LakeViewContext db = new LakeViewContext();
public IActionResult Index()
ICollection<Course> courses = db.Courses.ToList();
return View(courses);
[HttpGet]
public IActionResult CreateCourse()
return View("CreateCourse");
[HttpPost]
[ValidateAntiForgeryToken]
public IActionResult CreateCourse(CreateCourseViewModel courseVM)
if (ModelState.IsValid)
Course newCourse = new Course()
CourseCode = courseVM.CourseCode,
CourseTitle = courseVM.CourseTitle,
MasterOU = int.Parse(courseVM.MasterOU)
;
db.Courses.Add(newCourse);
db.SaveChanges();
return RedirectToAction("Index");
return View("CreateCourse", courseVM);
(粗体文字在 Visual Studio 中加下划线,错误相同
"私有 LakeViewContext db = new LakeViewContext();"
启动类:
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using LakeView.Models;
namespace LakeView
public class Startup
// This method gets called by the runtime. Use this method to add services to the container.
// For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
public void ConfigureServices(IServiceCollection services)
services.AddMvc();
var connection = @"Data Source = (localdb)\MSSQLLocalDB; Database = LakeViewData; Trusted_Connection = True;";
services.AddDbContext<LakeViewContext>(options => options.UseSqlServer(connection));
// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
//loggerFactory.AddConsole();
if (env.IsDevelopment())
app.UseDeveloperExceptionPage();
app.UseStaticFiles();
app.UseMvcWithDefaultRoute();
【问题讨论】:
【参考方案1】:LakeViewContext
期望将 DbContextOptions<LakeViewContext>
传递到其构造函数中。但是,您在没有提供任何内容的情况下调用构造函数:
private LakeViewContext db = new LakeViewContext();
要解决此问题,您只需插入已设置的依赖注入系统即可。为此,请按如下方式更改您的控制器:
public class CoursesController : Controller
private readonly LakeViewContext db;
public CoursesController(LakeVieContext db)
this.db = db;
...
ASP.NET Core 依赖注入系统将在构造函数中为您提供LakeViewContext
- 只需使用它即可。
【讨论】:
【参考方案2】:您正在尝试在控制器中新建 dbcontext 而不传递选项。
您应该改为向控制器添加一个构造函数,并将 dbContext 添加到您的构造函数中,这样它就会被注入,即
public CoursesController(LakeViewContext dbContext)
db = dbContext;
private LakeViewContext db;
... the rest of your code
依赖注入会传递给你
【讨论】:
【参考方案3】:在观察如何通过数据库优先方法生成类时,我能够使用空构造函数修复此错误。
public class MyDBContext : DbContext
public MyDBContext()
//Rest of your code
【讨论】:
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