Content for CRUD/EF scaffolding of Razor components

[danroth27]

This issue covers delivering scaffolders for building Razor components that are analogous to the existing scaffolders for Razor Pages and EF Core that exist today. These scaffolders are server specific and are generally not intended for client scenarios (Blazor WebAssembly or Blazor Hybrid). Admittedly this violates our principle that Blazor components should typically be hosting model agnostic. But the alternative is to generate components based on a custom data access abstraction that has implementations for both server and client including any required server API endpoints, which would be non-trivial.

Starting with an existing entity model class, there are two scaffolders to select from:

• Blazor components using Entity Framework
• Blazor components using Entity Framework (CRUD)

The CRUD scaffolder is a shorthand for creating pages for all five templates (Create, Delete, Details, Edit, List) supported by the non-CRUD scaffolder.

The "Blazor components using Entity Framework" scaffolder has the following options:

• Razor component name: The name of the specific component to generate
• Template: Select one of Create, Delete, Details, Edit, List
• URL: The URL path for the page
• Model class: Select an available model class
• DbContext class: Select an existing DbContext or create a new one. The appropriate packages and startup configuration code should be applied to project for EF Core based on the user's selection.
• Database provider: Select an available EF Core database provider when creating a new DbContext: SQL Server, SQLite, PostgreSQL, Azure Cosmos DB
• Use a layout component: Select from available layout components (inherit from LayoutComponentBase). A note should be added saying "(Leave empty to use the default layout)".

The "Blazor components using Entity Framework (CRUD)" scaffolder generates all of the template pages in one go. It has the same options as the "Blazor components using Entity Framework" scaffolder with the following exceptions:

• No Template option
• No URL option
• Add URL prefix option: The URL prefix to be used for all the generated pages (Blazor doesn't support folder-based routing conventions like Razor Pages does).

Sample generated code

I've converted the scaffolded content for Razor Pages to Blazor components: https://github.com/danroth27/BlazorScaffolding. There are a number of limitations in Blazor that we need to address:

• https://github.com/dotnet/aspnetcore/issues/49132
  • Blazor doesn't support the input tag helper. Instead the scaffolder will need to map the member type to an appropriate Blazor input component:
  • bool: InputCheckbox
  • DateTime, DateTimeOffset, DateOnly: InputDate
  • int, long, short, float, long, decimal: InputNumber
  • string: InputText
  • enum, enum[]: InputSelect
  • string: InputText
• https://github.com/dotnet/aspnetcore/issues/49147
  • Blazor doesn't support generating a display name at runtime. Instead, we'll need the scaffolder to determine an appropriate display name based on the member name and the [Display] attribute
• https://github.com/dotnet/aspnetcore/issues/45654
  • There are a bunch of places in the scaffolded code where we need the ability to return a 404 response. As a short term approach the proposed scaffolded code navigates to a non-existent notfound page to generate a 404 response.
• https://github.com/dotnet/aspnetcore/issues/51046
  • The scaffolded content assumes static server rendering, but the app might be setup with an interactive client router. To prevent rendering the scaffolded content on the client, the render mode may need to be set conditionally based on the request path.

@mkArtakMSFT @javiercn @stevesandersonms @DamianEdwards

[deepchoudhery]

Cool will keep track of this and see what items I can create for the upcoming .NET 8 preview 7.

[SteveSandersonMS]

The scaffolded content assumes static server rendering, but the app might be setup with an interactive router. We are still working through how we want to handle scenarios like this for .NET 8.

Ideally the scaffolded pages would work in either static SSR or InteractiveServer modes without any code changes. Since the same data access code would work both ways, this seems like it should be possible.

Of course, InteractiveWebAssembly is different because of forcing an API layer. I can certainly understand not wanting to support that in the short term.

[tjorvenK]

The issue described in here prevents me from using the scaffolded ui, after updating to .net 8. Is there any new information available, for a possible static ssr support for the components? Or an alternative workaround? :)

[danroth27]

The issue described in here prevents me from using the scaffolded ui, after updating to .net 8. Is there any new information available, for a possible static ssr support for the components? Or an alternative workaround? :)

@tjorvenK For a .NET 8 workaround, you can dynamically in code set the render mode of the router to be Static for specific request paths. It's not a pretty solution, but it is possible. The default identity UI included in the Blazor Web App template uses this technique when the app has global interactivity enabled. We plan to address this issue to provide a better solution in .NET 9.

[tjorvenK]

@tjorvenK For a .NET 8 workaround, you can dynamically in code set the render mode of the router to be Static for specific request paths. It's not a pretty solution, but it is possible. The default identity UI included in the Blazor Web App template uses this technique when the app has global interactivity enabled. We plan to address this issue to provide a better solution in .NET 9.

@danroth27 Thank you for the quick answer, I found the example you mentioned and I am excited for .NET 9 !