C#•7d ago

im watching a course about asp.net and creating some kind of web

but everytime i try to do "dotnet ef migrations add init" it says "Unable to create a 'DbContext' of type 'RuntimeType'. The exception 'Unable to resolve service for type 'Microsoft.EntityFrameworkCore.DbContextOptions`1[api.Data.ApplicationDBContext]' while attempting to activate 'api.Data.ApplicationDBContext'.' was thrown while attempting to create an instance. For the different patterns supported at design time, see https://go.microsoft.com/fwlink/?linkid=851728"

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23 Replies

Keswiik•7d ago

$code

MODiX•7d ago

To post C# code type the following: ```cs // code here ``` Get an example by typing $codegif in chat For longer snippets, use: https://paste.mod.gg/

`OP•7d ago

why ?

// using api.Models;
using Microsoft.EntityFrameworkCore;

namespace api.Data
{
    public class ApplicationDBContext : DbContext
    {
        
        public ApplicationDBContext(DbContextOptions<ApplicationDBContext> options) : base(options)
        {
        }

     
        public DbSet<Stock> Stock { get; set; }
        public DbSet<Comment> Comments { get; set; }
    }
}

// using api.Models;
using Microsoft.EntityFrameworkCore;

namespace api.Data
{
    public class ApplicationDBContext : DbContext
    {
        
        public ApplicationDBContext(DbContextOptions<ApplicationDBContext> options) : base(options)
        {
        }

     
        public DbSet<Stock> Stock { get; set; }
        public DbSet<Comment> Comments { get; set; }
    }
}

// namespace api.Models
{
    public class Comment
    {
        public int Id { get; set; }
        public string Title { get; set; } = string.Empty;
        public string Content { get; set; } = string.Empty;
        public DateTime CreatedOn { get; set; } =  DateTime.Now;
        public int? StockId { get; set; }
        //navigation property
        public Stock? Stock { get; set; }
    }
}

// namespace api.Models
{
    public class Comment
    {
        public int Id { get; set; }
        public string Title { get; set; } = string.Empty;
        public string Content { get; set; } = string.Empty;
        public DateTime CreatedOn { get; set; } =  DateTime.Now;
        public int? StockId { get; set; }
        //navigation property
        public Stock? Stock { get; set; }
    }
}

// using System.Net.Mime;
using System;
using System.Collections.Generic;
using System.Linq;
using System.ComponentModel.DataAnnotations.Schema;
using System.Threading.Tasks;


namespace api.Models
{
    public class Stock
    {
        public int Id { get; set; }
        public string Symbol { get; set; } = string.Empty;
        public string CompanyName { get; set; } = string.Empty;
        [Column(TypeName = "decimal(18,2)")]
        public Decimal Purchase { get; set; }
        [Column(TypeName = "decimal(18,2)")]
        public Decimal LastDiv { get; set; }
        public string Industry { get; set; } = string.Empty;
        public long MarketCap { get; set; }
        public List<Comment> Comment { get; set; } = new List<Comment>();
    }
}

// using System.Net.Mime;
using System;
using System.Collections.Generic;
using System.Linq;
using System.ComponentModel.DataAnnotations.Schema;
using System.Threading.Tasks;


namespace api.Models
{
    public class Stock
    {
        public int Id { get; set; }
        public string Symbol { get; set; } = string.Empty;
        public string CompanyName { get; set; } = string.Empty;
        [Column(TypeName = "decimal(18,2)")]
        public Decimal Purchase { get; set; }
        [Column(TypeName = "decimal(18,2)")]
        public Decimal LastDiv { get; set; }
        public string Industry { get; set; } = string.Empty;
        public long MarketCap { get; set; }
        public List<Comment> Comment { get; set; } = new List<Comment>();
    }
}

@ded like this?

Keswiik•7d ago

ya this all looks fine have you configured your asp app to have a dbcontext in your Startup.cs file?

`OP•7d ago

am i suppose to have a startup.cs file

Keswiik•7d ago

in most cases, yes

`OP•7d ago

Keswiik•7d ago

that is what asp will use to register services and configure the server

`OP•7d ago

program?

Keswiik•7d ago

show what's in program.cs also, fwiw, i would recommend using visual studio if you are new to c# not VSC

`OP•7d ago

ik i was jsut watching a course and it did it in vscode so i didnt wanna do anything wrong

// using api.Data;
using Microsoft.EntityFrameworkCore;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

builder.Services.AddDbContext<ApplicationDBContext>(options => {
    options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection"));
});

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseHttpsRedirection();

app.Run();

// using api.Data;
using Microsoft.EntityFrameworkCore;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

builder.Services.AddDbContext<ApplicationDBContext>(options => {
    options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection"));
});

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseHttpsRedirection();

app.Run();

Keswiik•7d ago

oh, top level statement asp project

`OP•7d ago

hm? wdym?

Keswiik•7d ago

it isn't using the asp web host, so I'm guessing that's why you're getting that error

`OP•7d ago

how do i use it?

Keswiik•7d ago

haven't set up EF in an asp project like this, but you could try: https://learn.microsoft.com/en-us/ef/core/cli/dbcontext-creation?tabs=dotnet-core-cli#from-a-design-time-factory

`OP•7d ago

okay thanks ill see @Keswiik yo actually tysm bro ive been trying to make this work for litteraly 3 days

`OP•7d ago

Keswiik•7d ago

for an explanation on why you were getting errors, look at this section: https://learn.microsoft.com/en-us/ef/core/cli/dbcontext-creation?tabs=dotnet-core-cli#from-application-services

`OP•7d ago

okay thank you

Keswiik•7d ago

:PepoSalute:

glhays•6d ago

Can you show the api.csproj file in this screenshot

SG97•6d ago

I think they're banned

Gaming

Programming

im watching a course about asp.net and creating some kind of web

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