Adding controller with Entity Framework failed - DbContext Error - entity-framework

Question

I have a .Net Core app with EntityFramework.
I wanted to add controller with CRUD operations.
But I got this error
I don't get any error while performing add-migration. It finds only one DbContext.
These are all the places where I have WebApplication8Context
WEBAPPLICATION8CONTEXT.CS
namespace WebApplication8.Data
{
public class WebApplication8Context : IdentityDbContext<ApplicationUser>
{
public WebApplication8Context(DbContextOptions<WebApplication8Context> options)
: base(options)
{
}
public DbSet<Tasks> Tasks { get; set; }
public DbSet<TaskGroups> TaskGroups { get; set; }
protected override void OnModelCreating(ModelBuilder builder)
{
base.OnModelCreating(builder);
// Customize the ASP.NET Identity model and override the defaults if needed.
// For example, you can rename the ASP.NET Identity table names and more.
// Add your customizations after calling base.OnModelCreating(builder);
}
}
IDENTITYHOSTINGSTARTUP.CS
[assembly: HostingStartup(typeof(WebApplication8.Areas.Identity.IdentityHostingStartup))]
namespace WebApplication8.Areas.Identity
{
public class IdentityHostingStartup : IHostingStartup
{
public void Configure(IWebHostBuilder builder)
{
builder.ConfigureServices((context, services) => {
services.AddDbContext<WebApplication8Context>(options =>
options.UseSqlServer(
context.Configuration.GetConnectionString("WebApplication8ContextConnection")));
services.AddDefaultIdentity<ApplicationUser>(options => options.SignIn.RequireConfirmedAccount = true)
.AddEntityFrameworkStores<WebApplication8Context>();
});
}
}
}
APPSETTINGS.JSON
{
"Logging": {
"LogLevel": {
"Default": "Information",
"Microsoft": "Warning",
"Microsoft.Hosting.Lifetime": "Information"
}
},
"AllowedHosts": "*",
"ConnectionStrings": {
"WebApplication8ContextConnection": "Server=CREATIVESM\\SQLEXPRESS;Database=MarApplication;Trusted_Connection=True;MultipleActiveResultSets=true"
}
}
BEGGINING OF MY WEBAPPLICATION8MODELSNAPSHOT
namespace WebApplication8.Migrations
{
[DbContext(typeof(WebApplication8Context))]
partial class WebApplication8ContextModelSnapshot : ModelSnapshot
{
protected override void BuildModel(ModelBuilder modelBuilder)
{
#pragma warning disable 612, 618
modelBuilder
.HasAnnotation("ProductVersion", "3.1.10")
.HasAnnotation("Relational:MaxIdentifierLength", 128)
.HasAnnotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn);
My Startup.cs
namespace WebApplication8
{
public class Startup
{
public Startup(IConfiguration configuration)
{
Configuration = configuration;
}
public IConfiguration Configuration { get; }
// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
services.AddControllersWithViews();
services.AddRazorPages();
// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
else
{
app.UseExceptionHandler("/Home/Error");
// The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
app.UseHsts();
}
app.UseHttpsRedirection();
app.UseStaticFiles();
app.UseRouting();
app.UseAuthentication();
app.UseAuthorization();
app.UseEndpoints(endpoints =>
{
endpoints.MapControllerRoute(
name: "default",
pattern: "{controller=Home}/{action=Index}/{id?}");
endpoints.MapRazorPages();
});
}
}
}
Other places where I can find WebApplication8Context are my migrations.
What am I doing wrong?

Answer 1

It looks like there is a conflict between IdentityHostingStartup and Startup.
Although I don't know the specific reason, you can use the following methods to solve it:
You can delete the code in your IdentityHostingStartup,then add it to your Startup like this:
services.AddDbContext<WebApplication8Context>(options =>
options.UseSqlServer(
Configuration.GetConnectionString("WebApplication8ContextConnection")));
services.AddDefaultIdentity<IdentityUser>(options => options.SignIn.RequireConfirmedAccount = true)
.AddEntityFrameworkStores<WebApplication8Context>();
services.AddControllersWithViews();
services.AddRazorPages();
Re-migration and update database,then you will add the controller successful.