database error when scaffoldingRSS

• • Reply
  marya

  Member

  16 Points

  18 Posts

  database error when scaffolding

  Feb 29, 2020 10:34 AM|marya|LINK

  i am having error when i tries to scaffold a controller "No database provide rhas been configured for this dbcontext. a provider can be configured  by overriding the db context.On Configuring method or by using Adddbcontext on the applocation service provider.if adddbcontext is used, then also ensure that your dbcontext type accpets a dbcontextoptions<TContext? object in its constructor  and passes it to the base constructor for DbContext".

  Here is what i haved done so far

  startup.cs

    public void ConfigureServices(IServiceCollection services)
          {
              services.AddDbContext<IntranetContext>(options => options.UseSqlServer(Configuration.GetConnectionString("DevConnection")));
              services.AddDefaultIdentity<IdentityUser>(options => options.SignIn.RequireConfirmedAccount = true)
                  .AddEntityFrameworkStores<ApplicationDbContext>();
              services.AddControllersWithViews();
              services.AddRazorPages();
          }

  appsettings.json

  {
    "Logging": {
      "LogLevel": {
        "Default": "Information",
        "Microsoft": "Warning",
        "Microsoft.Hosting.Lifetime": "Information"
      }
    },
    "AllowedHosts": "*",
    "ConnectionString": {
      "DevConnection": "Server= mypc;Database:ERP;Trusted_Connection=True;MultipleActiveResultSets=true"
    }
  }
  

  context file

  using Microsoft.EntityFrameworkCore;
  using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.Threading.Tasks;
  
  namespace Intranet
  {
      public class IntranetContext : DbContext
      {
          //public IntranetContext(DbContextOptions<IntranetContext> options) : base(options)
          //{
  
          //}
          public IntranetContext()
          // C# will call base class parameterless constructor by default
          {
          }
          public DbSet<GenerateDocumentNumber> GenerateDocumentNumber { get; set; }
          
      }
  }
  

• • Reply
  DA924

  Contributor

  4433 Points

  3754 Posts

  Re: database error when scaffolding

  Feb 29, 2020 12:55 PM|DA924|LINK

  If you are using 'options'  for the connectionstring, then you are implying that the service, an IoC,  will instance the object allowing dependency injection of the connectionstring object into the Dbcontext class/object, which you have commented out.

  https://docs.microsoft.com/en-us/ef/core/miscellaneous/configuring-dbcontext

  <copied>

  The DbContextOptions can be supplied to the DbContext by overriding the OnConfiguring method or externally via a constructor argument.
  If both are used, OnConfiguring is applied last and can overwrite options supplied to the constructor argument.

  <end>

  in startup.cs
  
  
  services.AddDbContext<PublishingCompanyContext>(options => options.UseSqlServer(Configuration["ConnectionStrings:DefaultConnection"]));
  
  
  the context....
  
  public partial class PublishingCompanyContext : DbContext
      {
          public PublishingCompanyContext(DbContextOptions<PublishingCompanyContext> options)
              : base(options)
          {
          }
  
          public virtual DbSet<Article> Article { get; set; }
          public virtual DbSet<Author> Author { get; set; }
          public virtual DbSet<Payroll> Payroll { get; set; }
  
          protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
          {
             
          }
           
  
  

  .

  If you find the post has answered your issue, then please mark post as 'answered'.
• • Reply
  Sherry Chen

  Participant

  1990 Points

  603 Posts

  Re: database error when scaffolding

  Mar 05, 2020 09:35 AM|Sherry Chen|LINK

  Hi marya ,

  marya

  No database provide rhas been configured for this dbcontext. a provider can be configured  by overriding the db context.On Configuring method or by using Adddbcontext on the applocation service provider.if adddbcontext is used, then also ensure that your dbcontext type accpets a dbcontextoptions<TContext? object in its constructor  and passes it to the base constructor for DbContext

  The error message says your DbContext( IntranetContext ) needs a constructor which accepts a DbContextOptions. So adding below constructor probably solves your problem.

   public class IntranetContext : DbContext
  {
          public IntranetContext(DbContextOptions<IntranetContext> options) : base(options)
          {
  
          }
          
          public DbSet<GenerateDocumentNumber> GenerateDocumentNumber { get; set; }
          
  }

  Reference: https://docs.microsoft.com/en-us/ef/core/miscellaneous/configuring-dbcontext

  Best Regards,

  Sherry

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