Multi tool use

Entity Framework core : DbContextOptionsBuilder' does not contain a definition for 'usesqlserver' and no extension method 'usesqlserver'

I'm new to EF core and I'm trying to get it to work with my asp.net core project.

I get the above error in my startup.cs when trying confiugure the dbcontext to use a connection string from config. I'm following this tutorial : https://docs.microsoft.com/en-us/aspnet/core/data/ef-mvc/intro

startup.cs

The problematic code in startup.cs :

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.SpaServices.Webpack;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.EntityFrameworkCore;
using tracV2.models;
using tracV2.data;

namespace tracV2
{
public class Startup
{
// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
// Add framework services.
services.AddMvc();

services.AddSingleton<IConfiguration>(Configuration);

string conn = Configuration.GetConnectionString("optimumDB");

services.AddDbContext<tracContext>(options => options.usesqlserver(conn));
}


The usesqlserver method is recognized if I put it directly into the context :

usesqlserver

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

namespace tracV2.data
{
public class tracContext : DbContext
{
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
optionsBuilder.UseSqlServer("myrealconnectionstring");
}


All my reasearch online points to missing references, but I can't seem to find out which one i'm missing(see image).references

Any help would be greatly appreciated,

Thanks

8 Answers
8

This is a known issue in the project system. See dotnet/project-system#1741

We install Microsoft.EntityFrameworkCore.SqlServer NuGet Package.

Microsoft.EntityFrameworkCore.SqlServer

PM > Install-Package Microsoft.EntityFrameworkCore.SqlServer


Then,

services.AddDbContext<AspDbContext>(options =>
options.UseSqlServer(config.GetConnectionString("optimumDB")));


adding
using Microsoft.EntityFrameworkCore;

using Microsoft.EntityFrameworkCore;

manually solved the problem for me

Found that here

I was using Visual Studio Code.

1) Try to install the package 'Microsoft.EntityFrameworkCore.SqlServer' by specifying the version number.

VS Code:

'dotnet add package Microsoft.EntityFrameworkCore.SqlServer -v 1.1.1'

Visual Studio:-

'Install-Package Microsoft.EntityFrameworkCore.SqlServer -v 1.1.1'

Refer the link 'Package 'Microsoft.EntityFrameworkCore.SqlServer' is incompatible with 'all' frameworks in the project' for doing it.

2) Then add the namespace 'using Microsoft.EntityFrameworkCore;' manually in the Startup.cs file.

Refer the below link
https://github.com/aspnet/EntityFramework/issues/7891.

3) If you get any dependency issue for 'Microsoft.EntityFrameworkCore.SqlServer.Design', like "Package 'Microsoft.EntityFrameworkCore.Design' is incompatible with 'all' frameworks in project" ,we need to run the below command,

VS Code:-

dotnet add package Microsoft.EntityFrameworkCore.Design -v 1.1

Visual Studio

Install-Package Microsoft.EntityFrameworkCore.Design -v 1.1

I believe this can be solved by adding a project reference to Microsoft.EntityFrameworkCore.SqlServer.Design

Install-Package Microsoft.EntityFrameworkCore.SqlServer.Design


Microsoft.EntityFrameworkCore.SqlServer wasn't directly installed in my project, but the .Design package will install it anyway as a prerequisite.

Copying the following code into the TodoApi.csproj from https://github.com/aspnet/Docs/tree/master/aspnetcore/tutorials/first-web-api/sample/TodoApi solved similar issue for me.

<Project Sdk="Microsoft.NET.Sdk.Web">

<PropertyGroup>
<TargetFramework>netcoreapp2.0</TargetFramework>
</PropertyGroup>

<ItemGroup>
<Folder Include="wwwroot" />
</ItemGroup>

<ItemGroup>
<PackageReference Include="Microsoft.AspNetCore.All" Version="2.0.0" />
</ItemGroup>

<ItemGroup>
<DotNetCliToolReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Tools" Version="2.0.0" />
</ItemGroup>

</Project>


Microsoft.AspNetCore.All may be excessive but it includes EntityFrameworkCore

I got around this by simply:

Add SqlServerDbContextOptionsExtensions to the class in question
Resolve SqlServerDbContextOptionsExtensions

SqlServerDbContextOptionsExtensions

SqlServerDbContextOptionsExtensions

This fixes the issue, must be missing some reference by default.

Follow the steps below.

Install Entity Framework Core Design and SQL Server database provider for Entity Framework Core:

dotnet add package Microsoft.EntityFrameworkCore.Design
dotnet add package Microsoft.EntityFrameworkCore.SqlServer


Import Entity Framework Core:

using Microsoft.EntityFrameworkCore;


And configure your DbContext:

var connectionString = Configuration.GetConnectionString("myDb");
services.AddDbContext<MyDbContext>(options =>
options.UseSqlServer(connectionString)
);


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