Mvc: `[Validation]` attributes do not work for page model properties or page handler parameters

[dougbu]

For example, a page handler such as
``` c#
public IActionResult OnGet([FromHeader, Required] string hosta)
{
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}

// ...
return Page();

}
`` should always return aBadRequestResultbecause thehostaheader doesn't exist. Instead, theModelState` is valid and everything proceeds.

Notes: [Validation] attributes do work as expected for action parameters. The above problem applies to all [Validation] attributes, not just [Required]. And, the [Validation] attributes are ignored with or without additional attributes; [FromHeader] doesn't matter.

[mkArtakMSFT]

I assume this is just a feature gap, where Razor Pages don't follow the same model. @danroth27 , is this something we should build up to work similar to mvc actions?

[danroth27]

I would think so, yes.

[mkArtakMSFT]

@NTaylorMullen, can you please confirm that we indeed don't have this area covered and that this is not a bug.

[dougbu]

Updating title because validation also produces no errors when binding a page model like the following and nothing is submitted:
c# public class IndexModel : PageModel { [BindProperty] [Required] public string Required { get; set; } }
I've tried a couple of [Validation] attributes and property types. The results are the same.

[NTaylorMullen]

Investigated and talked with folks. Here's what I found:

• It's an oversight that public IActionResult OnGet([FromHeader, Required] string hosta) does not change ModelState.IsValid when not provided.
• It's a bug that
  C# [BindProperty(SupportsGet = true), Required] public string Anything { get; set; } // On the page model
  doesn't result in ModelState.IsValid being false when not provided.

@pranavkm mentioned that he's going to start working on a fix for the bug.

[sven5]

Hi,

Which release will include these fixes?

[dougbu]

@sven5 the fix will be included in 2.1.0 Preview 2.

[sven5]

Hi,

I'm currently testing my Validation issue with preview 2.
It seems that MinLengthAttribute doesn't work.

My property is defined like this:
c# [BindProperty] [Required] [MinLength(1, ErrorMessage = "MinLengthAttribute_ValidationError")] public int[] SelectedStores { get; set; }

It doesn't result in ModelState.IsValid being false when SelectedStores.Count() == 0

Did I miss something?

Regards
Sven

[rynowak]

@sven5 - did you set the compatibility version to 2.1? https://github.com/aspnet/Mvc/blob/dev/samples/MvcSandbox/Startup.cs#L17

New features like this one in particular introduce lots of subtle behavior changes.

[sven5]

@rynowak

I missed that. Now it's working. Thank you.

There still is something strange:
The ModelState.Values Enumerable now contains my invalid property but the Key and SubKey are empty. I suspect that the consequence of this is that validation error for the field is not showing with

<span asp-validation-for="SelectedStores" class="text-danger"></span>

The validation error is displayed only in validation summary.

Regards
Sven

[rynowak]

@dougbu @pranavkm does this sound like https://github.com/aspnet/Mvc/issues/7503?

[dougbu]

@sven5 what exactly is in the request when the error ends up with an empty ModelState key?

@rynowak maybe.

[rynowak]

I'm reactivating this since there is something to figure out :)

[sven5]

Hi folks,

I figured it out now. It was a mistake on my side. Sorry for false alarm.
I had an issue with an array of hidden fields. The ModelState Value entry has been empty because the field was missing on post back.

Regards
Sven

[rynowak]

Ok, great thanks for lettings us know. Closing this