Entity Framework Core database

Question

I thought that I would learn to use ASP.NET Core, instead of what I am used to, ASP.NET, because Microsoft won't update ASP.NET anymore.

But I already got problems...

My problem is that I want to connect to my localdb file, and make this code-first table, but I get an error

No database provider has been configured for this DbContext.

even though I have a connection string for it:

"ConnectionStrings": {
    "DefaultConnection": "Server=(localdb)\\mssqllocaldb;Database=api;Trusted_Connection=True;"
  },

And I do include it in the startup, that it should use that connection string:

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

My table class is like this:

public class User
{
    public int UserId { get; set; }
    public string UserName { get; set; }
    public string Name { get; set; }
    public int age { get; set; }
}

And here is my Context:

public class UserContext : DbContext
{
    public DbSet<User> Users { get; set; }
}

Answer 1

您的 UserContext 应该具有接受 DbContextOptions 并将其传递给基本构造函数的公共构造函数。