ASP.NET core 3.1 :Adding Classes Libraries to the Project_ MissingMethodException: Method not found: 'Boolean Microsoft.EntityFrameworkCore.Migrations

Question

I'm working on asp.net-core 3.1 project, I have added 3 Class Library for my project to separate Access Data, Models class and Utility classes I resolved problems of matching folders etc. But when I run my project I get this Error:

MissingMethodException: Method not found: 'Boolean Microsoft.EntityFrameworkCore.Migrations.IMigrationsModelDiffer.HasDifferences(Microsoft.EntityFrameworkCore.Metadata.IModel, Microsoft.EntityFrameworkCore.Metadata.IModel)'.


   Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore.DatabaseErrorPageMiddleware.Invoke(HttpContext 
   httpContext)
   System.Runtime.CompilerServices.AsyncMethodBuilderCore.Start(ref TStateMachine 
   stateMachine)
   System.Runtime.CompilerServices.AsyncTaskMethodBuilder.Start(ref TStateMachine 
   stateMachine)
   Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore.DatabaseErrorPageMiddleware.Invoke(HttpContext 
   httpContext)
   Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

user_391994 · Answer

For me, the answer was to make sure all of my EF packages were pointing at the same 3.1.X version. I had inadvertently targeted a 5.0.0 EF package that included the missing method:

https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.migrations.imigrationsmodeldiffer.hasdifferences?view=efcore-5.0

user_14558655 · Answer

I found a solution can Help for ERROR:

MissingMethodException: Method not found: 'Boolean Microsoft.EntityFrameworkCore.Migrations.IMigrationsModelDiffer.HasDifferenc

https://github.com/dotnet/efcore/issues/22687

user_12575927 · Answer

A straight forward fix for me in Dotnet core 3.1 is to comment out

app.UseDatabaseErrorPage();

in the startup.cs file Configure Method

ASP.NET core 3.1 :Adding Classes Libraries to the Project_ MissingMethodException: Method not found: 'Boolean Microsoft.EntityFrameworkCore.Migrations

3 Answers