Culture Assigner

This section describes how to add a culture assigner selection dropdown.

Add IOptions<RequestLozalizationOptions> service.

services.Configure<RequestLocalizationOptions>(options =>
    {
        options.AddSupportedCultures("en", "fi", "sv");
        options.AddSupportedUICultures("en", "fi", "sv");
        options.SetDefaultCulture("en");
        options.FallBackToParentCultures = true;
        options.FallBackToParentUICultures = true;
    });

Add .UseRequestLocalization to 'app'.

RequestLocalizationOptions localizationOptions = app.Services.GetRequiredService<IOptions<RequestLocalizationOptions>>().Value;
app.UseRequestLocalization(localizationOptions);

Add Models/CultureAssignmentModel.cs

namespace samples.asp.Models;
using System.Globalization;

/// <summary>Culture assignment model</summary>
public record CultureAssignmentModel(CultureInfo CurrentUICulture, IList<CultureInfo> SupportedCultures);

Add Pages/Components/CultureAssignment/default.cshtml.

@using System.Globalization
@model samples.asp.Models.CultureAssignmentModel

<form id="culture-assignment">
    <select name="culture" onchange="this.parentElement.submit();">
        @foreach (CultureInfo culture in Model.SupportedCultures)
        {
            <option value="@culture.Name" selected="@(Model!.CurrentUICulture.Name == culture.Name)">@culture.DisplayName</option>
        }
    </select>
</form>

Add Pages/ViewComponents/CultureAssignmentViewComponent.cs.

namespace samples.asp.ViewComponents;
using System.Globalization;
using Microsoft.AspNetCore.Localization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Options;
using samples.asp.Models;

/// <summary></summary>
public class CultureAssignmentViewComponent : ViewComponent
{
    /// <summary>Options</summary>
    IOptions<RequestLocalizationOptions> localizationOptions;

    /// <summary>Create component</summary>
    public CultureAssignmentViewComponent(IOptions<RequestLocalizationOptions> localizationOptions)
    {
        // Assert not null
        ArgumentNullException.ThrowIfNull(localizationOptions);

        this.localizationOptions = localizationOptions;
    }

    /// <summary>Assign culture</summary>
    public IViewComponentResult Invoke()
    {
        // Get culture feature with assigned culture
        IRequestCultureFeature cultureFeature = HttpContext.Features.Get<IRequestCultureFeature>()!;
        // Create model with culture assignment record
        CultureAssignmentModel model = new CultureAssignmentModel(
            CurrentUICulture: cultureFeature.RequestCulture.UICulture,
            SupportedCultures: localizationOptions.Value.SupportedUICultures?.ToArray() ?? Array.Empty<CultureInfo>()
        );
        // Return partial view
        return View(model);
    }
}

Add @addTagHelper *, samples.asp to Pages/_ViewImports.cshtml.

@using samples.asp
@using samples.asp.Models
@namespace samples.asp.Pages
@addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers
@addTagHelper *, samples.asp

Add <vc:culture-assignment/> to Pages/Shared/_Layout.cshtml.

<div class="container">
    <a class="navbar-brand" asp-area="" asp-page="/Index">samples.asp</a>
    <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target=".navbar-collapse" aria-controls="navbarSupportedContent"
        aria-expanded="false" aria-label="Toggle navigation">
        <span class="navbar-toggler-icon"></span>
    </button>
    <div class="navbar-collapse collapse d-sm-inline-flex justify-content-between">
        <ul class="navbar-nav flex-grow-1">
            <li class="nav-item">
                <a class="nav-link text-dark" asp-area="" asp-page="/Index">Home</a>
            </li>
            <li class="nav-item">
                <a class="nav-link text-dark" asp-area="" asp-page="/Privacy">Privacy</a>
            </li>
        </ul>
    </div>
    <vc:culture-assignment/>
</div>