c# - 使用配置调用了 AddDbContext，但是上下文类型 'ContextClass' 只声明了一个无参数构造函数？

Question

详情

我正在尝试创建 asp.net 核心应用程序并使用 scaffold-dbcontext 生成类。当我运行这个应用程序时，它向我显示错误。我已经按照相同问题在 stackoverflow 上找到了一些答案，但我的问题仍然存在。 Question

我的语境

public partial class MyContext: DbContext
{

    public MyContext(DbContextOptions<MyContext> options) : base(options)
    {
    }


    public virtual DbSet<Answer> Answer { get; set; }
    public virtual DbSet<Attachment> Attachment { get; set; }
    public virtual DbSet<Category> Category { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {

        if (!optionsBuilder.IsConfigured)
        {
            optionsBuilder.UseSqlServer(@"Server=.;Database=MyContext;Trusted_Connection=True;");
        }
    protected override void OnModelCreating(ModelBuilder modelBuilder) { .... }
}

启动.cs

public void ConfigureServices(IServiceCollection services)
    {
        services.AddMvc();

        services.AddMvc()
       .AddJsonOptions(options =>
           options.SerializerSettings.PreserveReferencesHandling = PreserveReferencesHandling.All);

        services.AddDbContext<MyContext>(options => options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

    }

错误

AddDbContext was called with configuration, but the context type 'MyContext ' only declares a parameterless constructor. This means that the configuration passed to AddDbContext will never be used. If configuration is passed to AddDbContext, then 'MyContext ' should declare a constructor that accepts a DbContextOptions and must pass it to the base constructor for DbContext.

Answer 1

在 appsetting.json 文件中使用名称“DefaultConnection”声明您的连接字符串

"Data": {
   "DefaultConnection": "Data Source=(local); Initial Catalog=DBname; Integrated Security=True"
}