GKit.Reporting 1.0.0

GKit.Reporting

The library provide an extension method to the type IEnumerable<T> which produces a CSV string.

string csv = items.ToCsvString(b =>
    b.AddColumn("Number", p => p.Num)
    .AddColumn("Date", p => p.DateNow.ToString("dd/MM/yyyy HH:mm"))
    .AddColumn("Tit", p => p.Title));

XLSX reports

XlsReporter<T> writes a header row and one row per item, each value in its native cell type so Excel formats numbers and dates in the reader's locale rather than the server's.

var descriptors = new DescriptorsBuilder<Movement>()
    .Column("Codice", p => p.Code)
    .Column("Quantita", p => p.Quantity, "#,##0.00")   // Excel number format, per column
    .Column("Data", p => p.Date)
    .Build();

await new XlsReporter<Movement>("Movimenti", descriptors).WriteReportAsync(data, stream);

Styling without a subclass

XlsStyleOptions<T> is the third constructor argument. It carries a XlsTheme for the look of the whole sheet, an optional per-cell Resolve for the exceptions, and a PostProcess hook that runs against the finished sheet.

var styles = new XlsStyleOptions<Movement>
{
    Theme = XlsTheme.Default with
    {
        FontFamily = "Calibri",
        FontSize = 10,
        HeaderBackground = IndexedColors.Grey25Percent,
    },

    // Runs per cell. Return null to keep the style the theme gives it.
    Resolve = ctx => ctx is { Role: XlsCellRole.Data, Value: decimal and < 0 }
        ? new XlsCellStyle("negative", wb => wb.CreateCellStyle()
            .WithFont(wb.CreateFont().FontStyle("Calibri", 10).Color(IndexedColors.Red))
            .BorderStyle(BorderStyle.Thin))
        : null,

    PostProcess = (workbook, sheet) => sheet.CreateFreezePane(0, 1),
};

await new XlsReporter<Movement>("Movimenti", descriptors, styles).WriteReportAsync(data, stream);

Two things the design turns on:

• An options object holds recipes, never an ICellStyle. A style belongs to the workbook that created it, so one built ahead of time cannot be used by a second render. That is what makes an options object safe to build once and share — a DI singleton, a static, a [Parameter].
• A resolved style is named, and the name is its cache key. Returning the same key for a thousand cells creates one style, not a thousand: xlsx caps a workbook at roughly 64k cell styles, which a per-cell style reaches on an export of any size.

The Get*Style methods stay protected virtual for a reporter that is a type of its own — XlsGroupingReporter<T> is one — and a resolver takes precedence over them where it returns something. Grid exports reach all of this through GKit.UI.Data's ToXlsAsync and the grids' ExportStyles parameter.