Azure发布Web API时EF Core迁移未应用及连接字符串问题求助

Issue 1: Connection Strings in Environment-Specific Appsettings Not Recognized #

Possible Causes #

• Environment-specific appsettings.*.json files aren't being copied to the publish output.
• The ASPNETCORE_ENVIRONMENT variable isn't set correctly in Azure, so the app isn't loading the right config file.
• Azure's publish process prioritizes the root appsettings.json over environment files if there's a configuration loading mismatch.

Fixes #

• Ensure environment files are included in publish:
  Right-click appsettings.Development.json and appsettings.Production.json in Solution Explorer → Properties → Set Copy to Output Directory to Copy if newer.
• Set the environment variable in Azure:
  Navigate to your App Service → Configuration → Application Settings → Add a new entry with key ASPNETCORE_ENVIRONMENT and value Production (or your target environment).
• Use Azure's native connection string store (Recommended):
  Go to App Service → Configuration → Connection Strings → Add your production connection string here. This value will automatically override any appsettings entries, keeping sensitive data out of your codebase.

Issue 2: Migrations from Domains Project Not Applied During Publish #

Possible Causes #

• The BookingAPI project doesn't explicitly reference the assembly containing your migrations (the Domains project).
• EF Core can't locate the migration files because the DbContext is in a separate class library.

Fixes #

• Specify the migration assembly in Program.cs:
  When registering your ApplicationDBContext, explicitly tell EF Core where to find migrations using the Domains assembly:

  builder.Services.AddDbContext<ApplicationDBContext>(options =>
      options.UseSqlServer(builder.Configuration.GetConnectionString("YourConnStringKey"))
             .MigrationsAssembly(typeof(ApplicationDBContext).Assembly.FullName));
  

• Validate project references:
  Confirm BookingAPI has a project reference to the Domains class library (Right-click BookingAPI → Add → Project Reference → Select Domains).
• Configure publish settings to include migrations:
  In Visual Studio's publish profile wizard, go to the Database tab → Expand Entity Framework Core Migrations → Select your ApplicationDBContext (it should appear after setting the migration assembly). Enable the option to apply migrations during publish.

Bonus: Local Migration Command #

When creating migrations locally from the Domains project, use this command to target the BookingAPI as the startup project:

dotnet ef migrations add YourMigrationName --startup-project ../BookingAPI --project .

内容的提问来源于stack exchange，提问作者Srijani Ghosh