NumberFormat.NumberGroupSeparator is not working in Views in ASP.NET Core MVC

Question

In Startup.cs I have this code:

public void ConfigureServices(IServiceCollection services)
{
    ...

    services.Configure<RequestLocalizationOptions>(options =>
    {
         CultureInfo en_GB = new CultureInfo("en-GB");
         en_GB.NumberFormat.NumberDecimalSeparator = ".";
         en_GB.NumberFormat.NumberGroupSeparator = ",";

         CultureInfo[] supportedCultures = new[]
         {
             en_GB
         };

         options.DefaultRequestCulture = new RequestCulture(en_GB, en_GB);

         options.SupportedCultures = supportedCultures;
         options.SupportedUICultures = supportedCultures;
    });

    ...
}

And then when I return a decimal value from backend to a view

@model decimal

<span>@Model</span>

it renders the number (for example 123456789.012) as:

123456789.012

Whereas instead it should've been:

123,456,789.012

And I know that some of you will say that I can convert it to string in the view, for example:

@model decimal

@{
    var numberFormatter = new CultureInfo("en-GB").NumberFormat;
    numberFormatter.NumberDecimalSeparator = ".";
    numberFormatter.NumberGroupSeparator = ",";
    var myFormattedNumber = Model.ToString("#,###.###", numberFormatter);
}

<span>@Model</span>

And yes, this will show:

123,456,789.012

But I need a solution where I am not forced to convert the numbers manually to string in order to show the right format. Isn't there a possibility to do so automatically? Also, why is only NumberDecimalSeparator working properly (I can even use any other character instead of "." and it works, for example "~" or ";") but NumberGroupSeparator doesn't work at all. I also think there are similar issues with the other attributes of NumberFormat such as NumberDecimalDigits or NumberGroupSizes etc.

Answer 1

When you configure Localization in startup.cs, You also need to use Standard numeric format strings to format data in the View.

For Example:

I configure localization like this:

var app = builder.Build();
   
//i am using RequestLocalization middleware to configure localization in .Net 6
var defaultDateCulture = "en-GB";
var ci = new CultureInfo(defaultDateCulture);
ci.NumberFormat.NumberDecimalSeparator = "!";
ci.NumberFormat.NumberGroupSeparator = "~";

// Configure the Localization middleware
app.UseRequestLocalization(new RequestLocalizationOptions
{
    DefaultRequestCulture = new RequestCulture(ci),
    SupportedCultures = new List<CultureInfo>
    {
        ci,
    },
    SupportedUICultures = new List<CultureInfo>
    {
        ci,
    }
});

//..other middleware.... 

In the View, I use N key word to format common numeric type.

@model decimal

<h1>@Model.ToString("N")</h1>

Result:

You can see the format of decimal is what we set in localization.

Refer to this Docs to check more Standard numeric format strings.