问题
When trying to scaffold with asp.net core this command
scaffold-dbcontext "Data Source=(local);Initial Catalog=MyDb;Integrated Security=True;" Microsoft.EntityFrameworkCore.sqlserver -outputdir Models
Gives this error.
scaffold-dbcontext : The term 'scaffold-dbcontext' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again. At line:1 char:1 + scaffold-dbcontext "Data Source=(local);Initial Catalog=MyDB;In ... + ~~~~~~~~~~~~~~~~~~ + CategoryInfo : ObjectNotFound: (scaffold-dbcontext:String) [], CommandNotFoundException + FullyQualifiedErrorId : CommandNotFoundException
I have tried the solution here, but it does not work for me.
Any idea what the cause/cure could be?
回答1:
For me apparently it worked once I have also ran in Package Manager console :
Install-Package Microsoft.EntityFrameworkCore.Tools
Also make sure :
To have other dependencies (for example Microsoft.EntityFrameworkCore, Microsoft.EntityFrameworkCore.SqlServer, Microsoft.EntityFrameworkCore.SqlServer.Design...) referenced depending of your needs.
To select the right assembly as target for your commands in the top-right corner of the PM console (I am frequently fooled by forgetting it...)
Another problem I encountered : with the dbcontext located in a separate class library, I was encountering the following error :
Unable to find provider assembly with name Microsoft.EntityFrameworkCore.SqlServer. Ensure the specified name is correct and is referenced by the project.
Which I was able to fix by setting my class library as Startup project in VS (don't ask why as it seems meaningless, but it worked).
Late edit, there's something else to know : You can't run Scaffold-DbContext against a class library targetting only .Net Standard, you must also enable netcoreapp in it, or Scaffold-DbContext will complain.
To support both targets, edit the csproj to put : <TargetFrameworks>netcoreapp2.2;netstandard2.0</TargetFrameworks>
Instead of <TargetFramework> section.
After all these you'll be able to run your Scaffold-DbContext command line with proper arguments and connection string.
回答2:
- Make sure that this is available in your project.json file "Microsoft.EntityFrameworkCore.Tools.DotNet": "1.0.0-preview3-final".
- Run the command in the package manager console
that's all it will work
回答3:
If you're using .NetCore 2.2 the command below works like a charm for me on either command prompt or Git Bash. Make sure that you are directly on the project folder before running the command.
For example C:\App\ProjectName:
dotnet ef dbcontext scaffold "Server=.\;Database=Databasename;Trusted_Connection=True;" Microsoft.EntityFrameworkCore.SqlServer -o Model
回答4:
Make sure you run VS as Administrator and have installed packages: Microsoft.EntityFrameworkCore.SqlServer Microsoft.EntityFrameworkCore.SqlServer.Design Microsoft.EntityFrameworkCore.Tools
回答5:
I ran into another cause of this error recently: NuGet itself was out of date.
Updating NuGet resolved the issue.
If Devanathan's answer doesn't work for you, check to make sure NuGet itself is up to date.
回答6:
I had installed Microsoft.EntityFrameworkCore.Tools from NuGet Package Manager and it was visible in the installed packages. But I kept getting this error.
Restarting Visual Studio (2019/Version 16.4.4) fixed it for me.
回答7:
For me... when copy pasting the command from the microsoft docs, for some reason extra spacing was added around the hyphens.
Removing the hyphens fixed it:
wrong:
Scaffold - DbContext "Server=(localdb)\mssqllocaldb;Database=myDbName;Trusted_Connection=True;" Microsoft.EntityFrameworkCore.SqlServer - OutputDir Models
good:
Scaffold-DbContext "Server=(localdb)\mssqllocaldb;Database=myDbName;Trusted_Connection=True;" Microsoft.EntityFrameworkCore.SqlServer -OutputDir Models
The docs also say if you receive this error, try restarting Visual Studio.
https://docs.microsoft.com/en-us/ef/core/get-started/aspnetcore/existing-db
来源：https://stackoverflow.com/questions/39454545/the-term-scaffold-dbcontext-is-not-recognized-as-the-name-of-a-cmdlet-functio