Localised number format and wrong input type for decimal fields

[ygoe]

Describe the bug

With a model that contains a decimal property, this doesn't work with a locale that uses a decimal comma:

<input asp-for="Number">
<input asp-for="Number" type="number">

To Reproduce

Steps to reproduce the behavior:

1. Using this version of ASP.NET Core 2.1.5
2. Create the model class and the HTML razor view, then run it

Code:

class Model
{
    public decimal Number { get; set; } = 1.0m;
}

Expected behavior

This should be the rendered HTML:

<input type="number" name="Number" value="1.0">

This happens instead, for the two view variants from the top:

<input type="text" name="Number" value="1,0">
<input type="number" name="Number" value="1,0">

The first issue is that the decimal type isn't rendered with the type="number" attribute. If I fix this myself by adding the attribute, the field remains completely empty because there is a comma instead of a point in the value. This shouldn't be localised because then no browser or frontend library can handle the value anymore.

PS: I haven't even got to try what happens when the correct value "1.0" is sent back to the controller and the model binder should convert it to a decimal type. It probably fails for the same reason.

[User reference: Configuration/Endpoint/Edit/Factor]

[AndreasAmMueller]

Ran into the same bug and helped me out with a custom TagHelper that recognizes the For.ModelExplorer.ModelType as decimal or nullable decimal and then modifies the value attribute.

if (For.Model != null)
{
	decimal val = (decimal)For.Model;
	string value = val.ToString(CultureInfo.InvariantCulture);
	output.Attributes.SetAttribute(new TagHelperAttribute("value", value));
}

You also might want to set the "step" attrbute to "any".

For the .NET Core MVC Team:
I found some lines that are part of the bug, but I was not able to solve the wohle problem.

Lines found:

• The type should result in "number" not "text": https://github.com/aspnet/AspNetCore/blob/1aa50faa290ecda304507981cd01ed92651d5e34/src/Mvc/src/Microsoft.AspNetCore.Mvc.TagHelpers/InputTagHelper.cs#L51
• This line has the CultureInfo.CurrentCulture (for me, its de-DE!) as value. CultureInfo.InvariantCulture is needed to parse correctly: https://github.com/aspnet/AspNetCore/blob/1aa50faa290ecda304507981cd01ed92651d5e34/src/Mvc/src/Microsoft.AspNetCore.Mvc.Core/ModelBinding/Binders/DecimalModelBinder.cs#L80

[mkArtakMSFT]

Thanks for contacting us. We believe that the question you've raised have been answered. If you still feel a need to continue the discussion, feel free to reopen it and add your comments.

[ygoe]

@mkArtakMSFT Can you please explain why you believe the question has been answered / the bug has been fixed? I cannot see how this is the case. Please reopen until this has been fixed. In case you didn't know, there are other regions in the world than those that use a decimal point. And currently I can't use proper HTML with decimal numbers with ASP.NET Core MVC data binding.

[mkArtakMSFT]

Looks like I misread this. Reopening for further investigation.

[ygoe]

@mkArtakMSFT Did you want to reopen this issue?