[asp.net-core] Entity Framework Core: DbContextOptionsBuilder does not contain a definition for 'usesqlserver' and no extension method 'usesqlserver'

I am 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 configure the DbContext to use a connection string from config. I am following this tutorial.

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:

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 research online points to missing references, but I can't seem to find out which one I am missing (see image).

I had this issue, it seems that I hadn't added the required NuGet packages, although I thought I had done so, make sure to check them, one by one.

The Package is missing. Open Package Manager Console and execute the code below:

Install-Package Microsoft.EntityFrameworkCore.SqlServer 

As mentioned by top scoring answer by Win you may need to install Microsoft.EntityFrameworkCore.SqlServer NuGet Package, but please note that this question is using asp.net core mvc. In the latest ASP.NET Core 2.1, MS have included what is called a metapackage called Microsoft.AspNetCore.App

https://docs.microsoft.com/en-us/aspnet/core/fundamentals/metapackage-app?view=aspnetcore-2.2

You can see the reference to it if you right-click the ASP.NET Core MVC project in the solution explorer and select Edit Project File

You should see this metapackage if ASP.NET core webapps the using statement

<PackageReference Include="Microsoft.AspNetCore.App" />

Microsoft.EntityFrameworkCore.SqlServer is included in this metapackage. So in your Startup.cs you may only need to add:

using Microsoft.EntityFrameworkCore;

For me this issue happened with Visual Studio Code and I was able to fix with 2 steps:

1. Manually adding using Microsoft.EntityFrameworkCore;
2. Running dotnet build in terminal.

Project is works in DotNET Core 3.1+ or higher(future)

Add this package:

1. NuGet: Microsoft.EntityFrameworkCore.Tools
2. Project Config (.csproj): <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="3.1.8">

Install-Package:

**Microsoft.EntityFrameworkCore.SqlServer**

then add the top of your class:

**Microsoft.EntityFrameworkCore;**

that's worked for me

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)
);

Easy way to fix this issue

Error message:

Solution:
to install "microsoft.entityframeworkcore.sqlserver" with NuGet

Fixed :

PS: make sure you have using EF on the content "using Microsoft.EntityFrameworkCore;"

adding using Microsoft.EntityFrameworkCore;

manually solved the problem for me

Found that here

Edit...

for dotnet core 3.1 add

Microsoft.EntityFrameworkCore.SqlServer

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.

Wow so many answers yet none mentioned this Microsoft.EntityFrameworkCore.InMemory package!

Add the reference to this package: <PackageReference Include="Microsoft.EntityFrameworkCore.InMemory" Version="2.2.2" /> and you should be good to go.

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 had this trouble when I moved to Microsoft.EntityFrameworkCore.SqlServer v3.0.0 and Microsoft.EntityFrameworkCore.Tools v3.0.0

When I changed back to v2.2.6 on both libraries, the error went away. This is more of a workaround than a solution but it'll get you up and running till the issue is fixed.

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

In Visual Studio, check the NuGet Package Manager => Manage Packages for Solution, check all this packages, whether got installed in your solution or not, as below:

1. EntityFrameworkCore
2. Microsoft.EntityFrameworkCore
3. Microsoft.EntityFrameworkCore.InMemory
4. Microsoft.EntityFrameworkCore.Relational
5. Microsoft.EntityFrameworkCore.Sqlite.Core
6. Microsoft.EntityFrameworkCore.SqlServer
7. Microsoft.EntityFrameworkCore.Tools

I solved the same issues after check all the above packages have been installed.

Install package, EntityFrameworkCore.SqlServer:

PM> Install-Package Microsoft.EntityFrameworkCore.SqlServer -Version 3.1.3

Nuget: https://www.nuget.org/packages/Microsoft.EntityFrameworkCore.SqlServer/

Install the following packages from Nuget :-

1. Microsoft.EntityFrameworkCore
2. Microsoft.EntityFrameworkCore.Sqlite.Core

For anyone still having this problem: Use NuGet to install: Microsoft.EntityFrameworkCore.Proxies

This problem is related to the use of Castle Proxy with EFCore.

I had to use the line

 services.AddEntityFrameworkSqlite().AddDbContext<MovieContext>(options => options.UseSqlServer(Configuration.GetConnectionString("MovieContext")));

in the ConfigureServices method in the Startup.cs

I installed these three of them in the package manager console and it worked.

Install-Package Microsoft.VisualStudio.Web.CodeGeneration.Design -Version 3.1.4 Install-Package Microsoft.EntityFrameworkCore.Tools -Version 3.1.8 Install-Package Microsoft.EntityFrameworkCore.SqlServer -Version 3.1.8

First we install the Microsoft.EntityFrameworkCore.SqlServer NuGet Package:

PM > Install-Package Microsoft.EntityFrameworkCore.SqlServer

Then, after importing the namespace with

using Microsoft.EntityFrameworkCore;

we add the database context:

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

Currently working with Entity Framework Core 3.1.3. None of the above solutions fixed my issue.

However, installing the package Microsoft.EntityFrameworkCore.Proxies on my project fixed the issue. Now I can access the UseLazyLoadingProxies() method call when setting my DBContext options.

Hope this helps someone. See the following article:

Lazy Loading in EF Core

I had same issue but problem went off after going back and fixing DbContext incorrect syntax issue such as it should have been ExampleDbContextClass: DbContext whereas I had missed DbContext part in Context Class where you define your DbSet. Also, I verified following dependencies are needed in order to achieve connection to SqlServer. <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="3.1.0" /> <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer.Design" Version="1.1.6" /> Also verify that Version you install is less than your project's current version to be on safe side. Such as if your project is using 3.1 do not try to use newer one which would be for example 3.1.9. I had issue with that too.

I also had the same problem. I added the following. It works for me

Microsoft.EntityFrameworkCore.SqlServer

first add Install-Package Microsoft.EntityFrameworkCore.SqlServer

next add in your .cs file using Microsoft.EntityFrameworkCore;

finally add this in your core Startup.cs

  public void ConfigureServices(IServiceCollection services)
        {
            services.AddEntityFrameworkSqlServer().AddDbContext<ApplicationContext>(options => options.UseSqlServer(Configuration.GetConnectionString("MovieContext")));
        }

I got around this by simply:

Add SqlServerDbContextOptionsExtensions to the class in question Resolve SqlServerDbContextOptionsExtensions

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

If you are facing this issue in case of Sqlite then

. I think this is the problem with version of Sqlite,I had the same problem when I was using this versions of SqLite

Version 2.2.4:

After checking version here I changed the version then it worked.

No error after using this

Version 2.1.2:

your solution works great.

When I saw this video till 17 Minute: https://www.youtube.com/watch?v=fom80TujpYQ I was facing a problem here:

 services.AddDbContext<PaymentDetailContext>(options =>
    options.UseSqlServer(Configuration.GetConnectionString("DevConnection")));

UseSqlServer not recognizes so I did this Install-Package Microsoft.EntityFrameworkCore.SqlServer -Version 3.1.5

& using Microsoft.EntityFrameworkCore;

Then my problem is solved. About me: basically I am a purely PHP programmer since beginning and today only I started .net coding, thanks for good community in .net

Project -> ManageNugetPackages -> Browse -> Search "Microsoft.EntityFrameworkCore.SqlServer" and install or update.

Install below NuGet Package will solve your issue

Microsoft.EntityFrameworkCore.SqlServer

Install-Package Microsoft.EntityFrameworkCore.SqlServer

For asp.net core version 2.1 make sure to add the following package to fix the problem. (At least this fix the issue using SQLite)

dotnet add package Microsoft.EntityFrameworkCore.Sqlite
dotnet add package Microsoft.EntityFrameworkCore.Design

Here is the reference of the documentation using SQLite with entity framework core. https://docs.microsoft.com/en-us/ef/core/get-started/netcore/new-db-sqlite