Project type is asp.net MVC core. Adding a Razor View with or without Model I receive the following results:
There was an error running the selected code generator: 'Scaffolding failed. The path is empty. (Parameter 'path')'
Using VS2022 17.0.4 targeting .net 6.0 EntityFrameworkCore 6.0.1
I tried some of the remedies from the question that pops up on SO for VS2013:
cleaned out bin and obj folders and rebuilt
verified that all projects with EntityFrameWorkCore had the same version
BTW, adding a controller works.
Any help or guidance would be welcomed. This is a show stopper.
EDIT: I noticed that some or all of the projects in the solution were corrupted so I recreated project from scratch. I was able to add two views and then I received the message as above, again. Also, as I was building the project again I tested by adding a Razor view before I made any changes to the template generated project (asp.net core MVC) and it worked.
Something is corrupting one or more of my projects, and I think it might be NuGet. Any help would be greatly appreciated. I will now go rebuild the project from scratch for a third time and observe better and more frequently as to when the add Razor view fails.
I solved this issue by uninstalling the nuget package: Microsoft.AspNetCore.Identity
Reference
I got this error today while adding the Identity Scaffolded item to my existing Blazor server project.
I tried to add Identity Scaffolded item after updating the EF Core packages to 6.0.9 but unfortunately there seems to be some issue in the latest EF core packages.
So, I rolled back the EF Core packages from 6.0.9 to 6.0.8 and everything worked fine.
When I was recreating the solution from scratch I found the culprit. ME!
I do not like the new style of Main entry points where the code just starts without a namespace or class definition such as follows:
namespace MyNamespace
{
public static class MyClass
{
public static void Main(string[] args)
{
}
}
}
So I rewrote the class Program and created Startup and attempted to refactor all the code from Program. Obviously I did not do well. This caused my problem with the failed add of a templated Razor view.
download all packages the same version and cleaned up obj and bin file and rebuild your project. It worked for me
I was having the same issue and tried everything I could find to resolve it. - Made sure project would compile. Made sure all NuGet packages were the same version - 7.1. Looked for references to Microsoft.EntitiyFramework.Identity.
- No love.
Then I ran the latest Visual Studio updater to 17.4.3, I don't recall the version I as on, and we're good to go!
Related
After switching the all the projects to x86 architecture, I get the following error:
> dotnet ef migrations add Nullable-Fields --startup-project ..\LairageScanner.BlazorApp
Build started...
Build succeeded.
Could not load assembly 'LairageScanner.Context.SQL'. Ensure it is referenced by the startup project 'LairageScanner.BlazorApp'.
As seen above I have tried to run the command through CMD - but also done this for the package manager. I have seen some suggestion to fix this error: Stack Overflow & GitGub but neither of them had the solution to my issue.
Current Stack:
EF Core 3.1.3
Dotnet Core 3.1
Note: From the Git Solution it suggest converting to x64 and then just converting back later. And it does work. But I am looking for a more permanent solution.
I fixed it once with a simple action.
You need to be sure that the Startup Project is the one with the startup.cs file. Also, be sure that all Project references are complete.
Well, it worked for me.
Select the layer where the dbcontext class exists
I am very new to EntityFramework development, not to mention to .NetCore and MVC design pattern, I actually started with .NetCore development with a introduction book to those subjects, I reached a chapter where the autor starts with an MVC project (still using .NetCore 2.0) and do Scaffolding to create the EF model based on a Database previously created, then he jumps to add a controller via wizard, chosing the option that says: "MVC Controller with views, using Entity Framework", but when I do this, a get the error:
"There was an error running the selected code generator: ' Failed to
update dependency information for the project. Please restore the
project and try again."
I tried adding this files manually and detected that this happens when I try (or the wizard tries) to create the view file, either using an empty template or using one of the models, the result is the same.
I thought it was for the NuGet packages that where "asking" for updates, so I updated them, but nothing changed, I recreated the project several times, trying to leave the NuGet packages versions that the autor mentions to install, and to have "everything up to date" but still got the same.
I found another question in here with the same problem, and tried the possible solutions that mentions there, but none worked for me, I even try to install the versions 2.0.0 (or the lowest if there where no version 2.0.0) of the NuGet packages needed (or rather, mentioned by the author), and there was a change, still an error, but a different one, that says that the Microsoft.AspNetCore.Razor.Design.targets file needs a value on Configuration...?, still not know what to do, I noticed that updating 3 packages eliminates this error but is going back to the views error.
I don't know what else can I do or how to address this problem.
I finally made it work, although at the end, I don't know what was the problem, what I did was to uninstall all the NuGet packages, then reinstall one by one, chosing the 2.0.0 versions of each one (or the lowest if there was no 2.0.0 version) until there where no sintax errors (by the way, I already had done this, but I don't know what changed) and ended up with 13 packages installed, after verifying that the project builds correctly, I tried again to add via wizard the controller and the view and it threw another error asking to update just two packages (EntityFrameworkcore and EntityFrameworkCore.Design) to versions 2.0.3, after that, I was able to add both the controller and the views with no problem at all and the project still builds correctly.
Working on a .NETCore MVC back end that's using EntityFramework.
The Solution as a Service project, EntityFramework project, and an API (MVC) project. The API project is the envy point/startup.
It's an existing project, and there was an initial migration file which I used to setup the database from the command line using: dotnet ef database update.
Now, I've added a new model to the EntityFramework project, and added the appropriate public DbSet to the Context class. Now I'm trying to generate the update migration file for it so I can update the database.
Using dotnet ef migrations add migration_002 gave an error of:
Unable to create an object of type 'StartNetContext'. Add an
implementation of 'IDesignTimeDbContextFactory' to
the project, or see https://go.microsoft.com/fwlink/?linkid=851728 for
additional patterns supported at design time.
Searching for that turned up posts and blogs related to upgrades from EF 1 -> 2 ... not appropriate in this case. Or pointing to issues when creating the initial migration when there's also seeding happening... again, also not appropriate in this case. When I add the -v option, I get a bit more info:
Microsoft.EntityFrameworkCore.Design.OperationException: Unable to
create an object of type 'StartNetContext'. Add an implementation of
'IDesignTimeDbContextFactory' to the project, or see
https://go.microsoft.com/fwlink/?linkid=851728 for additional patterns
supported at design time. ---> System.MissingMethodException: No
parameterless constructor defined for this object.
Ugh. What? Why do I need that? Searching that points to re-arranging how the startup is configured... specifically making sure that the. AddDbContext is being called - which it is...
I feel like I'm going in circles... it should work... someone created the initial migration, so it had to have worked, right?
NOTE: I'm on a Mac, so there's no using the Package Manager console, so selecting target projects, etc isn't a solution either. This all needs to be done right from the CLI.
Add the following class in your main project.
public class DesignTimeDbContextFactory : IDesignTimeDbContextFactory<YourDbContext>
{
public YourDbContext CreateDbContext(string[] args)
{
IConfigurationRoot configuration = new ConfigurationBuilder()
.SetBasePath(Directory.GetCurrentDirectory())
.AddJsonFile("appsettings.json")
.Build();
DbContextOptionsBuilder<YourDbContext> builder = new DbContextOptionsBuilder<YourDbContext>();
string connectionString = configuration.GetConnectionString("YourDbContextConnectionName");
builder.UseSqlServer(connectionString);
return new YourDbContext(builder.Options);
}
}
Hope your error will go away!
So it turns out in my case it was a simple flag on the CLI... Despite having the web api project marked as the startup project in the solution, I needed to specify it on the command line as well.
dotnet ef migrations add migration_002 -s ../MyWebApp.Api
I got that from this post.
Adding the -s flag worked, even without the code and adding the class (which I did try first, but ran into problems with the return statement).
It's the simple things in life.
Here's what I am looking at
PM> Add-Migration AddedSubdivion -StartUpProjectName Data -Verbose
Using StartUp project 'Data'.
Using NuGet project 'Registry'.
Could not load assembly 'Registry'. (If you are using Code First Migrations inside
Visual Studio this can happen if the startUp project for your solution does not
reference the project that contains your migrations. You can either change the startUp
project for your solution or use the -StartUpProjectName parameter.)
I have no idea why it's trying to reference the Registry project. Registry depends on Data, not the other way around. I am very new to this, so I'd appreciate any help.
This is embarrassing, but maybe this will help out a googler in the future.
At the top of the "Package Manager Console" my default project was set to the wrong project. Changing that to my models project fixed it.
This can also be caused by a platform mismatch between .NET Core and your project. You get the error:
Could not load assembly 'DataProject'. Ensure it is referenced by the startup project 'ProgramProject'.
even though you have specified correct project and startup project names. (Either by using the drop down boxes in VS and the Package Manager Console, or by using the -project and -startupproject parameters.)
You can fix it by switching to Any CPU instead of x86, or vice-versa (or maybe to x64, etc.), but then you will have to switch back and forth every time you need to make changes to your model/DB.
As per this answer you can fix this by changing the order of your .NET Core path entries in system environment variables. If you're getting this error, then it means that either the first .NET Core path is for x64 but you're trying to make changes to your x86 project, or possibly other way around. Move the one you're targeting above the one you're not targeting, save, and then restart Visual Studio.
You can see which one is currently being used with the command dotnet --info.
(Note that this assumes you've installed both. You may also only have one of them installed, in which case you'd need to install the other one, and then check the order of the PATH entries; if the second one you installed is the one you want, then you will definitely need to change the PATH order to make it the one used by VS, since its entry should be at the bottom.)
The problem might not be so obvious if you have Package Manager Console docked with a narrow window...hiding the default project.
Its needs a wide docking.
If all fails there's always the verbose flag (-v).
A command like dotnet ef database update -v should help clarify the problem ef is facing.
In my case, the issue stemmed from EntityFramework finding it difficult to deal with the fact that my platform target was changed from AnyCPU to x86 or x64.
System.BadImageFormatException: Could not load file or assembly 'MyProject, Culture=neutral, PublicKeyToken=null'. An attempt was made to load a program with an incorrect format.
Temporarily changing the platform target to AnyCPU worked just fine.
Make sure that you are focused on:
1- Startup Projects is UI (MVC, API, ... etc).
2- Default project in package manager console is place of (ApplicationDbContext).
I would like to add, if you are using .net6 preview, you will need to update the packages.
so you will need to use the preview versions EntityFrameworkCore.Tools and EntityFrameworkCore.SqlServer (6.0.0-rc-1.21452.10 version as of today)
I had this exact problem, and it turned out because I createdthe project under a blank solution and then added the class libraies and web app seperately it didnt have a start up project.
None of these worked for me. I temporarily unloaded the unrelated project from the solution, ran the command, and then loaded the project back in.
I've got this issue migrating an Asp.Net 5 to Asp.Net 6.
The problema was in the .csproj file.
This configuration
<PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">
<PlatformTarget>x86</PlatformTarget>
</PropertyGroup>
I've just removed this property group and the dotnet ef worked
This can also be caused by a platform mismatch between .NET Core and
Also check this in your packages
if don't have that package Dependency Injection
Its very simple you have to install dependency injection package
The package manager window has a Default Project Property.
Setting the default project in the package manager window fixed this for me.
I also had to set the startup project to the same application in the solution explorer.
You should define 2 constructor and OnConfiguring method in context.cs. And also in your UI layer you should define connection string.
Like this:
In Context.cs :
public Context()
{
}
public Context(DbContextOptions<Context> options) : base(options)
{
}
protected override void OnConfiguring(DbContextOptionsBuilder
optionsBuilder)
{
if (!optionsBuilder.IsConfigured)
{
optionsBuilder.UseSqlServer("Data Source=..");
}
}
In appsetting.json:
"ConnectionStrings": {
"SqlServer": "Data Source=....."
}
In Program.cs:
builder.Services.AddDbContext<Context>(opt =>
{
opt.UseSqlServer(builder.Configuration.GetConnectionString("SqlServer"));
});
Set the target project for the migration as the startup project and continue
I have created a module to be included in a main MVC3 web application. The module is packaged into a NuGet package and it can be installed and uninstalled via NuGet. Both, the main site and the module use Code First, EF >= 4.3
To create the package I have another MVC3 site and all the functionality is inside an area, so to create the package I just pack the libraries, the views and all the needed files. Database Migrations work fine in the project and the package is created nicely.
Now I install the package in the main site via NuGet. This site is in another solution, and the solution has two projects:
MyProject.Web.UI: this is an Mvc3 project
MyProject.EntityFramework: this is a class library with all the models, dbContext for MyProject...
The package is installed correctly and the Area, the Area views and libraries are correctly installed.
The problem now is how I update the database? I've tried first to run "Update-Database" but I get the message:
"No migrations configuration type was found in the assembly
'MyProject.Web.UI'. (In Visual Studio you can use the
Enable-Migrations command from Package Manager Console to add a
migrations configuration)."
I've tried then to enable the migrations with "Enable-Migrations" but I got this other message:
"No context type was found in the assembly 'MyProject.Web.UI'."
I tried also just to run the site and see if the changes are automatically applied but I get the exception page with the typical message:
"The model backing the 'NugetPackageDbContext' context has changed
since the database was created. Consider using Code First Migrations
to update the database"
I don't know what to do to update the database with the required changes in migrations that come in the NuGet package. Any one could put some light here in this matter? I'm quite new to Migrations, maybe there are some configs to update the database if there is a change instead of running the commands in the console, I'm a bit lost.
Thanks in advance :)
Good news! It seems that I got it. I was looking for a way to make the NuGet package to update the database to the latest version.
Well, this package comes with an Admin controller, so I added a new action called Update:
public ActionResult Update()
{
System.Data.Entity.Database.SetInitializer(new System.Data.Entity.MigrateDatabaseToLatestVersion<MyPackageDbContext, MyPackage.Migrations.Configuration>());
return View();
}
In my Configuration class for the migrations I have:
public Configuration()
{
AutomaticMigrationsEnabled = true;
}
I have to say that in my way to do all of this I've found a few strange behaviors. One thing that surprises me is this, I don't know if this is normal, read the secuence:
Package installed with new migrations but database not up to date. So if I access the EF this affected by this I get the exception about this. Ok up to this.
I go to my action /MyPackage/Admin/Update and run it. Apparently it runs. I go to the database and I don't see changes. Even the migrations table does not have a new row.
I access again the EF part that displayed the exception before (point number 1) and then everything goes through, database is updated and the migrations table shows the new line.
One thing that you have to notice is that the Configuration class is internal, but because this is a module I needed to be accessible from another assembly. I tried to make it public but I got some strange warnings/errors that I don't know if they are related. So in the end I kept it internal but used
[assembly: System.Runtime.CompilerServices.InternalsVisibleTo("OtherAssembly")]
I've found a few of strange behaviors in Visual Studio with all this stuff of the NuGet packages, CF, migrations ... I don't know if these things are bugs, but all this thing took me two full working days.
I hope it is useful for any other that wants to create a CF NuGet package that is updateable.
In package manager console you will need to the Default project to MyProject.EntityFramework
You may also need to make sure MyProject.Web.UI is set as the start up project (in case there are multiple), then you can pass in the connection string into update command:
Update-Database -ConnectionStringName MyConnStringName
This should update the database correctly, unless there is data that will be lost.
If your DbContext is in MyProject.EntityFramework then the Default Project in the Package Manager Console needs to be set to MyProject.EntityFramework before you can use Update-Database.
I realize that this question is very old, but since I don't see this answer I'll throw it in anyway.
To perform migrations and such on projects or external references you can still use the same three command:
Enable-Migrations
Add-Migration
Update-Database
but you wil need to supply some additional parameters. For the Enable-Migrations command you will need to add the -ContextTypeName and optionally the -ContextAssemblyName commands like so:
Enable-Migrations -ContextTypeName MyProject.EntityFramework.NugetPackageDbContext -ContextAssemblyName MyProject
This will give you a migration configuration class in your current project. The other two commands will require you to specify this configuration class:
Update-Database -ConfigurationTypeName MyProject.Web.UI.Migrations.Configuration
Hope that helps