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I am trying to figure out the recommended way to call a class that will seed my database on application startup in an ASP.NET Core 2.1 app.

The SeedDatabase.cs class is not static because it relies on several repositories registered in ConfigureServices which are injected through the constructor.

I remember when you used to call a seed class in the Configure method, but I believe they recommend way of calling it in 2.1 is in the Program.cs main method. However, if I do this it would only work if the class was static, in my case dependency injection fails.

Blake Rivell
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  • Can you share your code for dependency injection – Md. Abdul Alim Aug 07 '18 at 14:09
  • @Md.AbdulAlim I think I am getting somewhere now using this post: https://learn.microsoft.com/en-us/aspnet/core/security/authorization/secure-data?view=aspnetcore-2.1 It appears you do make it a class with a static Initialize method that accepts an IServiceProvider which is passed in from the Main method in program.cs. The only thing I have remaining to figure out is how to use serviceProvider.getRequiredService to access my registered services. – Blake Rivell Aug 07 '18 at 14:12
  • It does not matter your SeedDatabase.cs is non static. What do you want with SeedDatabase.cs? Is it DbContext or not? – Md. Abdul Alim Aug 07 '18 at 14:20
  • @Md.AbdulAlim It is a class that does not use Entity Framework. It simply injects a bunch of my repositories and calls methods on them to insert objects. – Blake Rivell Aug 07 '18 at 14:22
  • Is it inherit from interface? – Md. Abdul Alim Aug 07 '18 at 14:28
  • @Md.AbdulAlim Nope, did you go to the link that I posted. Go there and ctrl+f on "SeedData". You will see how they are calling it. My biggest issue now is using the passed in IServiceProvider, the functions are not available. – Blake Rivell Aug 07 '18 at 14:30
  • See this https://stackoverflow.com/questions/46222692/asp-net-core-2-seed-database – Md. Abdul Alim Aug 07 '18 at 14:33
  • You have to add the using statement. Just type fully one of the methods that should be there like `GetRequiredService` and then hit CTRL+(period). That will bring up a context menu where you can select to add the using. – Chris Pratt Aug 07 '18 at 14:57

2 Answers2

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Alter Program.cs along the lines of:

public static void Main(string[] args) =>
    MainAsync(args).ConfigureAwait(false).GetAwaiter().GetResult();

public static async Task MainAsync(string[] args)
{
    var host = CreateWebHostBuilder(args).Build();
    // do something
    await host.RunAsync().ConfigureAwait(false);
}

public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
    WebHost.CreateDefaultBuilder(args)
        .UseStartup<Startup>();

In the // do something part, you now have access to the built host object, which also means you have access to your services. You'll have to use the service locator anti-pattern here, which is actually okay for this particular use case.

There's a number of approaches you could take. You could actually register your SeedDatabase class in ConfigureServices and then pull it out here, but that's pretty atypical. This will only be used once, so it's not something that really deserves to be registered in your service collection. There better approach is to actually make that a static class and change your method(s) that actually do the work to take your context as a param. Then, you can just do something like:

using (var scope = host.Services.CreateScope())
{
    var context = scope.ServiceProvider.GetRequiredService<YourContext>();
    await SeedDatabase.SeedFoosAsync(context);
}
Chris Pratt
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  • I was thinking about making the method static and pass in an IServiceProvider. Then use the serviceProvider.getService method. Does this make sense? Also is it really necessary to make everything in the Program.cs file. I am trying to keep it as close the 2.1 default as possible, simple calling my SeedDatabase.Initialize() static method. – Blake Rivell Aug 07 '18 at 14:40
  • Like I said: multiple approaches. The key parts are getting `host.Services` (your `IServiceProvider` and using `CreateScope`, which is necessary to get at any scoped or transient services. How you go from there is pretty much you own thing. – Chris Pratt Aug 07 '18 at 14:42
  • Alright, so from the default 2.1 Startup.cs what is the simplest way to edit it so I can get host.Services and call a custom functions passing something into it? – Blake Rivell Aug 07 '18 at 14:43
  • Not from `Startup`, but from `Program`, and as I just showed you above. `Startup` doesn't give you the access you need at any point. – Chris Pratt Aug 07 '18 at 14:48
  • I believe I am getting somewhere now. I simple needed to remove the .Run() chain and set var host = var host = CreateWebHostBuilder(args).Build(); – Blake Rivell Aug 07 '18 at 14:52
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    Yes, that's technically all that's required, but you should really take the async approach. Any time you're doing I/O (such as communicating with a database), async is a good idea. – Chris Pratt Aug 07 '18 at 14:54
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I got my pies back thanks to Chris's answer :) I was working through an example on Pluralsight and am only just learning .NET Core.

Here is what worked

using System;
using Microsoft.AspNetCore;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.DependencyInjection;
using BethanysPieShop.Models;

namespace BethanysPieShop
{
    public class Program
    {
        public static void Main(string[] args)
        {
            var host = CreateWebHostBuilder(args).Build();

            using (var scope = host.Services.CreateScope())
            {
                var services = scope.ServiceProvider;

                try
                {
                    var context = services.GetRequiredService<AppDbContext>();

                                        DbInitializer obj = new DbInitializer();
                obj.Seed(context);
                }
                catch (Exception)
                {
                    //we could log this in a real-world situation
                }

                host.Run();
            }
        }

        public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
            WebHost.CreateDefaultBuilder(args)
                .UseStartup<Startup>();
    }
}

Here is my DbInitializer class

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace BethanysPieShop.Models
{
    public class DbInitializer
    {
        public void Seed(AppDbContext context)
        {
            if (!context.Pies.Any())
            {
                context.AddRange(
                new Pie { Name = "Apple Pie", Price = 12.95M, ShortDescription = "Our famous apple pies!", LongDescription = "Icing carrot cake jelly-o cheesecake. Sweet roll marzipan marshmallow toffee brownie brownie candy tootsie roll. Chocolate cake gingerbread tootsie roll oat cake pie chocolate bar cookie dragée brownie. Lollipop cotton candy cake bear claw oat cake. Dragée candy canes dessert tart. Marzipan dragée gummies lollipop jujubes chocolate bar candy canes. Icing gingerbread chupa chups cotton candy cookie sweet icing bonbon gummies. Gummies lollipop brownie biscuit danish chocolate cake. Danish powder cookie macaroon chocolate donut tart. Carrot cake dragée croissant lemon drops liquorice lemon drops cookie lollipop toffee. Carrot cake carrot cake liquorice sugar plum topping bonbon pie muffin jujubes. Jelly pastry wafer tart caramels bear claw. Tiramisu tart pie cake danish lemon drops. Brownie cupcake dragée gummies.", ImageUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/applepie.jpg", IsPieOfTheWeek = true, ImageThumbnailUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/applepiesmall.jpg" },
                new Pie { Name = "Blueberry Cheese Cake", Price = 18.95M, ShortDescription = "You'll love it!", LongDescription = "Icing carrot cake jelly-o cheesecake. Sweet roll marzipan marshmallow toffee brownie brownie candy tootsie roll. Chocolate cake gingerbread tootsie roll oat cake pie chocolate bar cookie dragée brownie. Lollipop cotton candy cake bear claw oat cake. Dragée candy canes dessert tart. Marzipan dragée gummies lollipop jujubes chocolate bar candy canes. Icing gingerbread chupa chups cotton candy cookie sweet icing bonbon gummies. Gummies lollipop brownie biscuit danish chocolate cake. Danish powder cookie macaroon chocolate donut tart. Carrot cake dragée croissant lemon drops liquorice lemon drops cookie lollipop toffee. Carrot cake carrot cake liquorice sugar plum topping bonbon pie muffin jujubes. Jelly pastry wafer tart caramels bear claw. Tiramisu tart pie cake danish lemon drops. Brownie cupcake dragée gummies.", ImageUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/blueberrycheesecake.jpg", IsPieOfTheWeek = false, ImageThumbnailUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/blueberrycheesecakesmall.jpg" },
                new Pie { Name = "Cheese Cake", Price = 18.95M, ShortDescription = "Plain cheese cake. Plain pleasure.", LongDescription = "Icing carrot cake jelly-o cheesecake. Sweet roll marzipan marshmallow toffee brownie brownie candy tootsie roll. Chocolate cake gingerbread tootsie roll oat cake pie chocolate bar cookie dragée brownie. Lollipop cotton candy cake bear claw oat cake. Dragée candy canes dessert tart. Marzipan dragée gummies lollipop jujubes chocolate bar candy canes. Icing gingerbread chupa chups cotton candy cookie sweet icing bonbon gummies. Gummies lollipop brownie biscuit danish chocolate cake. Danish powder cookie macaroon chocolate donut tart. Carrot cake dragée croissant lemon drops liquorice lemon drops cookie lollipop toffee. Carrot cake carrot cake liquorice sugar plum topping bonbon pie muffin jujubes. Jelly pastry wafer tart caramels bear claw. Tiramisu tart pie cake danish lemon drops. Brownie cupcake dragée gummies.", ImageUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/cheesecake.jpg", IsPieOfTheWeek = false, ImageThumbnailUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/cheesecakesmall.jpg" },
                new Pie { Name = "Cherry Pie", Price = 15.95M, ShortDescription = "A summer classic!", LongDescription = "Icing carrot cake jelly-o cheesecake. Sweet roll marzipan marshmallow toffee brownie brownie candy tootsie roll. Chocolate cake gingerbread tootsie roll oat cake pie chocolate bar cookie dragée brownie. Lollipop cotton candy cake bear claw oat cake. Dragée candy canes dessert tart. Marzipan dragée gummies lollipop jujubes chocolate bar candy canes. Icing gingerbread chupa chups cotton candy cookie sweet icing bonbon gummies. Gummies lollipop brownie biscuit danish chocolate cake. Danish powder cookie macaroon chocolate donut tart. Carrot cake dragée croissant lemon drops liquorice lemon drops cookie lollipop toffee. Carrot cake carrot cake liquorice sugar plum topping bonbon pie muffin jujubes. Jelly pastry wafer tart caramels bear claw. Tiramisu tart pie cake danish lemon drops. Brownie cupcake dragée gummies.", ImageUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/cherrypie.jpg", IsPieOfTheWeek = false, ImageThumbnailUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/cherrypiesmall.jpg" },
                new Pie { Name = "Christmas Apple Pie", Price = 13.95M, ShortDescription = "Happy holidays with this pie!", LongDescription = "Icing carrot cake jelly-o cheesecake. Sweet roll marzipan marshmallow toffee brownie brownie candy tootsie roll. Chocolate cake gingerbread tootsie roll oat cake pie chocolate bar cookie dragée brownie. Lollipop cotton candy cake bear claw oat cake. Dragée candy canes dessert tart. Marzipan dragée gummies lollipop jujubes chocolate bar candy canes. Icing gingerbread chupa chups cotton candy cookie sweet icing bonbon gummies. Gummies lollipop brownie biscuit danish chocolate cake. Danish powder cookie macaroon chocolate donut tart. Carrot cake dragée croissant lemon drops liquorice lemon drops cookie lollipop toffee. Carrot cake carrot cake liquorice sugar plum topping bonbon pie muffin jujubes. Jelly pastry wafer tart caramels bear claw. Tiramisu tart pie cake danish lemon drops. Brownie cupcake dragée gummies.", ImageUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/christmasapplepie.jpg", IsPieOfTheWeek = false, ImageThumbnailUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/christmasapplepiesmall.jpg" },
                new Pie { Name = "Cranberry Pie", Price = 17.95M, ShortDescription = "A Christmas favorite", LongDescription = "Icing carrot cake jelly-o cheesecake. Sweet roll marzipan marshmallow toffee brownie brownie candy tootsie roll. Chocolate cake gingerbread tootsie roll oat cake pie chocolate bar cookie dragée brownie. Lollipop cotton candy cake bear claw oat cake. Dragée candy canes dessert tart. Marzipan dragée gummies lollipop jujubes chocolate bar candy canes. Icing gingerbread chupa chups cotton candy cookie sweet icing bonbon gummies. Gummies lollipop brownie biscuit danish chocolate cake. Danish powder cookie macaroon chocolate donut tart. Carrot cake dragée croissant lemon drops liquorice lemon drops cookie lollipop toffee. Carrot cake carrot cake liquorice sugar plum topping bonbon pie muffin jujubes. Jelly pastry wafer tart caramels bear claw. Tiramisu tart pie cake danish lemon drops. Brownie cupcake dragée gummies.", ImageUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/cranberrypie.jpg", IsPieOfTheWeek = false, ImageThumbnailUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/cranberrypiesmall.jpg" },
                new Pie { Name = "Peach Pie", Price = 15.95M, ShortDescription = "Sweet as peach", LongDescription = "Icing carrot cake jelly-o cheesecake. Sweet roll marzipan marshmallow toffee brownie brownie candy tootsie roll. Chocolate cake gingerbread tootsie roll oat cake pie chocolate bar cookie dragée brownie. Lollipop cotton candy cake bear claw oat cake. Dragée candy canes dessert tart. Marzipan dragée gummies lollipop jujubes chocolate bar candy canes. Icing gingerbread chupa chups cotton candy cookie sweet icing bonbon gummies. Gummies lollipop brownie biscuit danish chocolate cake. Danish powder cookie macaroon chocolate donut tart. Carrot cake dragée croissant lemon drops liquorice lemon drops cookie lollipop toffee. Carrot cake carrot cake liquorice sugar plum topping bonbon pie muffin jujubes. Jelly pastry wafer tart caramels bear claw. Tiramisu tart pie cake danish lemon drops. Brownie cupcake dragée gummies.", ImageUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/peachpie.jpg", IsPieOfTheWeek = false, ImageThumbnailUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/peachpiesmall.jpg" },
                new Pie { Name = "Pumpkin Pie", Price = 12.95M, ShortDescription = "Our Halloween favorite", LongDescription = "Icing carrot cake jelly-o cheesecake. Sweet roll marzipan marshmallow toffee brownie brownie candy tootsie roll. Chocolate cake gingerbread tootsie roll oat cake pie chocolate bar cookie dragée brownie. Lollipop cotton candy cake bear claw oat cake. Dragée candy canes dessert tart. Marzipan dragée gummies lollipop jujubes chocolate bar candy canes. Icing gingerbread chupa chups cotton candy cookie sweet icing bonbon gummies. Gummies lollipop brownie biscuit danish chocolate cake. Danish powder cookie macaroon chocolate donut tart. Carrot cake dragée croissant lemon drops liquorice lemon drops cookie lollipop toffee. Carrot cake carrot cake liquorice sugar plum topping bonbon pie muffin jujubes. Jelly pastry wafer tart caramels bear claw. Tiramisu tart pie cake danish lemon drops. Brownie cupcake dragée gummies.", ImageUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/pumpkinpie.jpg", IsPieOfTheWeek = true, ImageThumbnailUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/pumpkinpiesmall.jpg" },
                new Pie { Name = "Rhubarb Pie", Price = 15.95M, ShortDescription = "My God, so sweet!", LongDescription = "Icing carrot cake jelly-o cheesecake. Sweet roll marzipan marshmallow toffee brownie brownie candy tootsie roll. Chocolate cake gingerbread tootsie roll oat cake pie chocolate bar cookie dragée brownie. Lollipop cotton candy cake bear claw oat cake. Dragée candy canes dessert tart. Marzipan dragée gummies lollipop jujubes chocolate bar candy canes. Icing gingerbread chupa chups cotton candy cookie sweet icing bonbon gummies. Gummies lollipop brownie biscuit danish chocolate cake. Danish powder cookie macaroon chocolate donut tart. Carrot cake dragée croissant lemon drops liquorice lemon drops cookie lollipop toffee. Carrot cake carrot cake liquorice sugar plum topping bonbon pie muffin jujubes. Jelly pastry wafer tart caramels bear claw. Tiramisu tart pie cake danish lemon drops. Brownie cupcake dragée gummies.", ImageUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/rhubarbpie.jpg", IsPieOfTheWeek = true, ImageThumbnailUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/rhubarbpiesmall.jpg" },
                new Pie { Name = "Strawberry Pie", Price = 15.95M, ShortDescription = "Our delicious strawberry pie!", LongDescription = "Icing carrot cake jelly-o cheesecake. Sweet roll marzipan marshmallow toffee brownie brownie candy tootsie roll. Chocolate cake gingerbread tootsie roll oat cake pie chocolate bar cookie dragée brownie. Lollipop cotton candy cake bear claw oat cake. Dragée candy canes dessert tart. Marzipan dragée gummies lollipop jujubes chocolate bar candy canes. Icing gingerbread chupa chups cotton candy cookie sweet icing bonbon gummies. Gummies lollipop brownie biscuit danish chocolate cake. Danish powder cookie macaroon chocolate donut tart. Carrot cake dragée croissant lemon drops liquorice lemon drops cookie lollipop toffee. Carrot cake carrot cake liquorice sugar plum topping bonbon pie muffin jujubes. Jelly pastry wafer tart caramels bear claw. Tiramisu tart pie cake danish lemon drops. Brownie cupcake dragée gummies.", ImageUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/strawberrypie.jpg", IsPieOfTheWeek = false, ImageThumbnailUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/strawberrypiesmall.jpg" },
                new Pie { Name = "Strawberry Cheese Cake", Price = 18.95M, ShortDescription = "You'll love it!", LongDescription = "Icing carrot cake jelly-o cheesecake. Sweet roll marzipan marshmallow toffee brownie brownie candy tootsie roll. Chocolate cake gingerbread tootsie roll oat cake pie chocolate bar cookie dragée brownie. Lollipop cotton candy cake bear claw oat cake. Dragée candy canes dessert tart. Marzipan dragée gummies lollipop jujubes chocolate bar candy canes. Icing gingerbread chupa chups cotton candy cookie sweet icing bonbon gummies. Gummies lollipop brownie biscuit danish chocolate cake. Danish powder cookie macaroon chocolate donut tart. Carrot cake dragée croissant lemon drops liquorice lemon drops cookie lollipop toffee. Carrot cake carrot cake liquorice sugar plum topping bonbon pie muffin jujubes. Jelly pastry wafer tart caramels bear claw. Tiramisu tart pie cake danish lemon drops. Brownie cupcake dragée gummies.", ImageUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/strawberrycheesecake.jpg", IsPieOfTheWeek = false, ImageThumbnailUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/strawberrycheesecakesmall.jpg" }
            );
        }

        context.SaveChanges();
    }
}

}

Ed Sansbury
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