EF Core Add Migration Debugging

Question

How can I step into OnModelCreating with a breakpoint and see if my logic is wrong or if the ModelBuilder is doing something I'm not expecting? I've seen lots of posts on how to debug the actual migration, but nothing on how to watch how the model code is being generated.

I'm trying to implement some custom attributes on some of my entities, and it's being ignored; I'd like to see what my configuration is doing as it's generating the model code.

Possible duplicate of [Can one set a breakpoint in EF code first migrations seed method?](https://stackoverflow.com/questions/28858289/can-one-set-a-breakpoint-in-ef-code-first-migrations-seed-method) — Michael Freidgeim, Feb 19 '18 at 11:00
They may have similar answers, but they are entirely different questions. — Jeremy Holovacs, Feb 21 '18 at 13:09

score 101 · Accepted Answer · answered Jan 20 '17 at 21:43

101

You should be able to call Debugger.Launch() in your code. The just-in-time debugger should prompt you to attach a debugger when it hits that line.

answered Jan 20 '17 at 21:43

bricelam

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5

Thanks! That's twice you've helped me. :) – Jeremy Holovacs Jan 22 '17 at 12:41
4

It's my job. ;) I try to make sure people can use what I create. Every question asked becomes input into future enhancements. – bricelam Jan 23 '17 at 16:37
@bricelam should this work in EF Core 2.0 as well? Debugger will not attach correctly there. – TGlatzer Sep 05 '17 at 14:38
I'm trying to attach a Debugger, but it won't step into my code. Are there any prerequisits? – TGlatzer Dec 08 '17 at 13:56
A win32 exception is being thrown for me(ef core2.0) -- kernelbase.pdb not loaded – IEnjoyEatingVegetables Apr 06 '18 at 12:13
2

@JohnOsborne, I'm having the same problem when calling Debugger.Launch(); in the OnConfiguring method of my DbContext while running Add-Migration – Inx51 Apr 06 '18 at 20:57
@lnx51 any luck? – IEnjoyEatingVegetables Apr 07 '18 at 23:59
1

Hey everyone - try `Debugger.Break()` instead. – Adam Jan 19 '21 at 19:15
`System.Diagnostics.Debugger.Launch();` if you don't want to amend the referenced namespaces. – SharpC Sep 27 '22 at 11:55

score 2 · Answer 2 · answered Mar 06 '20 at 05:37

An alternate method would be to create your own console app or unit test and debug that. Use this snippet by bricelam from the ef github issue

using (var db = new MyDbContext())
{
    var reporter = new OperationReporter(
        new OperationReportHandler(
            m => Console.WriteLine("  error: " + m),
            m => Console.WriteLine("   warn: " + m),
            m => Console.WriteLine("   info: " + m),
            m => Console.WriteLine("verbose: " + m)));

    var designTimeServices = new ServiceCollection()
        .AddSingleton(db.GetService<IHistoryRepository>())
        .AddSingleton(db.GetService<IMigrationsIdGenerator>())
        .AddSingleton(db.GetService<IMigrationsModelDiffer>())
        .AddSingleton(db.GetService<IMigrationsAssembly>())
        .AddSingleton(db.Model)
        .AddSingleton(db.GetService<ICurrentDbContext>())
        .AddSingleton(db.GetService<IDatabaseProvider>())
        .AddSingleton<MigrationsCodeGeneratorDependencies>()
        .AddSingleton<ICSharpHelper, CSharpHelper>()
        .AddSingleton<CSharpMigrationOperationGeneratorDependencies>()
        .AddSingleton<ICSharpMigrationOperationGenerator, CSharpMigrationOperationGenerator>()
        .AddSingleton<CSharpSnapshotGeneratorDependencies>()
        .AddSingleton<ICSharpSnapshotGenerator, CSharpSnapshotGenerator>()
        .AddSingleton<CSharpMigrationsGeneratorDependencies>()
        .AddSingleton<IMigrationsCodeGenerator, CSharpMigrationsGenerator>()
        .AddSingleton<IOperationReporter>(reporter)
        .AddSingleton<MigrationsScaffolderDependencies>()
        .AddSingleton<MigrationsScaffolder>()
        .BuildServiceProvider();

    var scaffolder = designTimeServices.GetRequiredService<MigrationsScaffolder>();

    var migration = scaffolder.ScaffoldMigration(
        "MyMigration",
        "MyApp.Data");

    File.WriteAllText(
        migration.MigrationId + migration.FileExtension,
        migration.MigrationCode);
    File.WriteAllText(
        migration.MigrationId + ".Designer" + migration.FileExtension,
        migration.MetadataCode);
    File.WriteAllText(migration.SnapshotName + migration.FileExtension,
        migration.SnapshotCode);
}

EF Core Add Migration Debugging

2 Answers2

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