There was an error running the selected generator

问题:

When I create the Scaffold and add the Model class then I am getting these error "There was an error running the selected generator . try rebuilding the project"

I have three Model class :

1.Department.CS

2.Designation.cs

3.CompanyDBContext.cs

Database : I have two table in database, 1. Department(deptID,deptName,Description) 2. Designation(desgtID,desgName,description)

Objective :- I want to create one view page for these scenario. Like this

Insert Name of Form (TextBox) + Department Name (Dropdown list box) + Designation Name (Dropdown list box)

1.Department.CS

namespace mvcAppraisalSystem.Models
{
  public class Department
  {
    [Key]
    public int deptID { get; set; }
    public string deptName { get; set; }
    public string Description { get; set; }
  }
 }

2.Designation.cs

namespace mvcAppraisalSystem.Models
{
   public class Designation
   {
      [Key]
      public int desgID { get; set; }
      public string desgName { get; set; }
      public string description { get; set; }
   }
 }

3.CompanyDBContext.cs

 namespace mvcAppraisalSystem.Models
 {
   public class CompanyDBContext : DbContext
   {
      public DbSet<CompanyDBContext> Departments { get; set; }

      public DbSet<CompanyDBContext> Designations { get; set; }
   }
 }

回答1:

This is the problem with the connection string you can change the connection string with your DbContext name like bellow on the file web.config:

<connectionStrings>
  <add name="MovieDBContext" connectionString="Data Source=(LocalDb)\v11.0;AttachDbFilename=|DataDirectory|\aspnet-MVCmove-20140616082808.mdf;Initial Catalog=aspnet-MVCmove-20140616082808;Integrated Security=True" providerName="System.Data.SqlClient" />
</connectionStrings>

For the class:

using System;
using System.Data.Entity;
namespace MVCmove.Models
{
  public class Movie
  {
    public int ID { get; set; }
    public string Title { get; set; }
    public DateTime ReleaseDate { get; set; }
    public string Default1Genre { get; set; }
    public decimal Price { get; set; }
  }
  public class MovieDBContext : DbContext
  {    
    public DbSet<Movie> Movies { get; set; }
  }
}

回答2:

I got this error attempting to build my first Scaffolded item on a newly created project using database first EF.

It's important to Build the Project after adding a new Entity Data Model. Apparently, it's necessary to initialize/configure aspects of the project.

I had read about this previously in a database first tutorial, but had forgotten it. Eventually, I remembered it after digging through related SO issues, including this one.

回答3:

I built the project as they suggested in the error: "Try rebuilding the project". And then I tried it once again. And the error was gone. The creation of new project did not work in my case me. Running a build did.

回答4:

Hope this helps someone. I tried some of the suggestions in SO but in my case, it was something else. I forgot that I had created a partial class where I keep my Data Annotations which had a property that I removed from the model/database. So, after I updated the model from the database, project compiled fine I didn't notice any issue. But, later on when I tried to create a controller with scaffolding, EF started throwing "There was an error running the selected generator. try rebuilding the project". I finally able to resolve the issue after I remembered and removed the property from the partial class.

回答5:

I renamed Model, then tried to add controller again, then I renamed Model to first name. After that creating of the controller was successful.

回答6:

I was getting the same error above on VS2017 also.

My Solution was to unload my project and then edit the csproj file and look for the reference to System.Web.MVC and deleted it, then saved and reloaded the project. I then went to manage NuGet packages and you can then Reinstalled Microsoft.AspNet.Mvc package.

Cleaned and rebuilt the solution and tried to add the controller again and it worked!!

回答7:

No idea if anyone else has had this issue since but restarting Visual Studio removed the error for me in VS2017.