Du C# en entrée.
Des rapports en sortie.

// RunGetData une seule fois, puis RunRender pour chaque format.
await report.RunGetData(null);

foreach (var (filename, format) in new[] {
    ("report.pdf",  OutputPresentationType.PDF),
    ("report.xlsx", OutputPresentationType.Excel2007),
    ("report.csv",  OutputPresentationType.CSV),
    ("report.html", OutputPresentationType.HTML),
}) {
    var ofs = new OneFileStreamGen(filename, true);
    await report.RunRender(ofs, format);
}

/* Dans la DataSource du RDL */
<ConnectionProperties>
  <DataProvider>Json</DataProvider>
  <ConnectString>file=employees.json</ConnectString>
</ConnectionProperties>

var rdlXml = (await File.ReadAllTextAsync("Employees.rdl"))
    .Replace("employees.json", Path.Combine(baseDir, "employees.json"));

var parser = new RDLParser(rdlXml) { Folder = baseDir };
using var report = await parser.Parse();
await report.RunGetData(null);
await report.RunRender(new OneFileStreamGen("out.pdf", true), OutputPresentationType.PDF);

/* QrCode · BarCode128 · BarCode39 · DataMatrix · AztecCode · Pdf417 · ITF-14 */
<CustomReportItem Name="ProductQR">
  <Type>QrCode</Type>
  <CustomProperties>
    <CustomProperty>
      <Name>Code</Name>
      <Value>=Fields!ProductName.Value</Value>
    </CustomProperty>
  </CustomProperties>
</CustomReportItem>

var parameters = new Dictionary<string, string>
    { ["BarcodeType"] = "DataMatrix" };
await report.RunGetData(parameters);

record SaleRecord(string Product, string Region, decimal Amount, int Quantity);

var salesData = new List<SaleRecord>
{
    new("Widget A", "North", 1250.00m, 50),
    new("Widget B", "South", 840.50m,  33),
};

await report.DataSets["Data"].SetData(salesData);
await report.RunGetData(null);
await report.RunRender(ofs, OutputPresentationType.PDF);