Validating against a duplicate entry in ASP.NET 5 MVC 6

Service layer and project structure in ASP.NET MVC 5 without repository and UoW patterns

There is no reason to use a Unit of Work pattern with Entity Framework if you have no need to create a generic data access mechanism. You would only do this if you were:...using a data access technology that did not natively support a Unit of work pattern (EF does)...Wanted to be able to swap out data providers sometime in the future.. however, thi...

Separation of concerns and n-tiered architecture in ASP.NET 5/ASP.NET Core 1

If you ask 10 civil architects to build you a bridge, you’ll end up having 10 different architectures. Not one will be the same and not one will be better than the other. ...Regardless of how many best practices and design patterns they apply, each architect will justify their idea. Some will be overzealous while others will keep it simple and ge...

ASP.NET 5 EF 7 cannot update entry in database table

Change your repository method like below. This may help. Let us know what happens...public object GetPackageById(int id) { return _context.PackageVersions.AsNoTracking().SingleOrDefault(p => p.Id ==id); }

ASP.net core 2.0 MVC every new database migrations includes data from previous migrations

Another alternative is to make sure the mappings are correct and just delete the up/down functions to have a clean state:...https://github.com/aspnet/EntityFrameworkCore/issues/11763

how to setup EFcore database first in separate class library in ASP.NET Core MVC application?

I have a DB and I want to add a separate class library for entity framework to access my data but when I run scaffold command it makes a DB model in my web application.

Problem running project after Identity scaffolding in ASP.NET Core MVC project on Linux

I've tried adding ...<PackageReference Include="Microsoft.AspNetCore.Razor.Runtime" Version="2.2.0" /> ...However 2.2.0 is the latest version available at this time, which doesn't match the error. The error is still the same after rebuilding the app....project.csproj:...<Project Sdk="Microsoft.NET.Sdk.Web"> <PropertyGroup> <TargetFramework>ne...

How to update(by merging) edmx without override the model classes in asp.net mvc

I am developing an application in asp.net mvc. I use entity framework as ORM. I have a problem. To use javascript unobstrusive validation, I need to add annotation to model objects. For example; [Required], [EMailAddress]. But when we add something to the database and update it, all model classes are override, and all annotations disappear. Or, as ...

ASP.NET Core MVC Entity Framework Core: the context type 'DatenbankKontext' only declares a parameterless constructor

The error is telling you that you need to add a constructor that takes options....'DatenbankKontext' should declare a constructor that accepts a DbContextOptions and must pass it to the base constructor for DbContext....So add one:...public class DatenbankKontext : DbContext { public DatenbankKontext(DbContextOptions options) : base(opt...

Duplicate table created when adding IdentityUser as foreign key in ASP.NET Core 3.1

You need to define the relationship between ...AccountModel... and ...IdentityUser... in your model builder....Something along the lines of ... protected override void OnModelCreating(ModelBuilder builder) { builder.Entity<AccountModel>() .HasOne(accountModel=> accountModel.User); base.OnModelCreating(builder); ...

SQL Connection string issue when deploying ASP.NET Core MVC to Azure App Service (Linux)

The publish wizard simply handles the database creation/migration for you, it doesn't modify your project, as that's 1) not its purpose and 2) it can't make the configuration decision for you (i.e. use appsettings, environment variables, etc.)...You need to provide the connection string in production via configuration, just as in development. Since...