Culture & Localized Formatting — Lumeo Documentation

How it works

Every Lumeo component that renders a date or a number (DataGrid cells, DatePicker, DateTimePicker, NumberInput, Slider, Statistic, DataGrid exports …) formats its output with CultureInfo.CurrentCulture by default. That means ASP.NET's request-localization middleware drives the look of dates and numbers with zero extra wiring — a de-DE user sees 15.03.2026 and 1.234,56 €, an en-US user sees 3/15/2026 and $1,234.56.

Wiring ASP.NET request localization

In Program.cs, configure the supported cultures and add the middleware — this is the standard ASP.NET Core pattern and nothing in Lumeo is required beyond it:

builder.Services.Configure<RequestLocalizationOptions>(opts =>
{
    var supported = new[] { "en-US", "de-DE", "fr-FR" };
    opts.SetDefaultCulture(supported[0])
        .AddSupportedCultures(supported)
        .AddSupportedUICultures(supported);
});

var app = builder.Build();
app.UseRequestLocalization();

Overriding per component

Every component listed below exposes a Culture parameter that wins over CurrentCulture. This is useful when the app locale and the UI locale differ — e.g. render a German-formatted KPI inside an English admin console.

@using System.Globalization

<DataGrid TItem="Invoice"
          Items="_invoices"
          Columns="_columns"
          Culture="@_de" />

<DatePicker @bind-Value="_date" Culture="@_de" />

<NumberInput @bind-Value="_amount" Culture="@_de" />

<Statistic Title="Revenue" Value="1234.56" Precision="2" Culture="@_de" />

@code {
    private readonly CultureInfo _de = CultureInfo.GetCultureInfo("de-DE");
}

Components honouring the Culture parameter today: DataGrid, DatePicker, DateTimePicker, NumberInput, Slider, Statistic.

Culture in exports

IDataGridExportService.ToCsv / ToExcel / ToPdf all accept an optional CultureInfo. The DataGrid passes its effective culture automatically, so the downloaded CSV, .xlsx, and PDF match what the user sees on screen.

@inject IDataGridExportService Export

var bytes = Export.ToExcel(items, exportColumns,
    sheetName: "Invoices",
    culture: CultureInfo.GetCultureInfo("de-DE"));

await Export.DownloadAsync(bytes, "invoices.xlsx",
    "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");

ClosedXML writes native date / number cells with a format string — Excel then renders them using the workbook locale when the file is opened. Lumeo picks sensible defaults based on the supplied culture's ShortDatePattern and ShortTimePattern.

Formatting vs. translated UI text

Culture controls how values render (dates, numbers, currency). Localization controls how UI chrome text renders (buttons, placeholders, empty-state copy). They are two separate axes — you can ship an app with English UI that still formats numbers as 1.234,56 for a German user.

UI text translation lives in ILumeoLocalizer (registered by AddLumeo()). Lumeo ships English and German strings out of the box — add or override any key via the AddLumeo(opts => …) overload.