how to render rdlc local report to pdf with itextsharp via filestream in vb.net

In order to render, you need to first convert to byte array.

using Microsoft.Reporting.WebForms; // Make sure to add reference to Microsoft.ReportViewer.WebForms or Microsoft.Reporting.WinForms
using iTextSharp.text;
using iTextSharp.text.pdf;
using System.IO;
using System.Collections.Generic; // Required for Warning[]

public static byte[] RenderReportToPDF(LocalReport report, string deviceInfo)
{
    string mimeType, encoding, extension;
    Warning[] warnings;
    string[] streams;

    byte[] renderedBytes = report.Render(
        "PDF",
        deviceInfo,
        out mimeType,
        out encoding,
        out extension,
        out streams,
        out warnings);

    return renderedBytes;
}

public static void ExportRdlcToPdf(LocalReport report, string filePath, string deviceInfo = "<DeviceInfo><OutputFormat>PDF</OutputFormat></DeviceInfo>")
{
    try
    {
        byte[] pdfBytes = RenderReportToPDF(report, deviceInfo);

        // Create a new PDF document from the rendered bytes
        using (FileStream fileStream = new FileStream(filePath, FileMode.Create))
        {
            using (Document document = new Document())
            {
                PdfWriter writer = PdfWriter.GetInstance(document, fileStream);
                document.Open();
                using (MemoryStream ms = new MemoryStream(pdfBytes))
                {
                    PdfReader reader = new PdfReader(ms);
                    for (int page = 1; page <= reader.NumberOfPages; page++)
                    {
                        document.NewPage();
                        PdfImportedPage importedPage = writer.GetImportedPage(reader, page);
                        document.Add(new PdfContentByte(writer).AddTemplate(importedPage, 0, 0));
                    }
                }
            }
        }
    }
    catch (System.Exception ex)
    {
        // Handle exceptions appropriately, e.g., logging
        Console.WriteLine($"Error exporting to PDF: {ex.Message}");
        throw; // Re-throw or handle as needed
    }
}

// Example Usage:
// Create a LocalReport instance
// var report = new LocalReport();
// report.ReportPath = "Path/To/Your/Report.rdlc";
// report.DataSources.Add(new ReportDataSource("YourDataSourceName", yourData));

// Example DeviceInfo (optional, but recommended for high resolution):
// string deviceInfo = "<DeviceInfo><OutputFormat>PDF</OutputFormat><PageWidth>8.5in</PageWidth><PageHeight>11in</PageHeight><MarginTop>0.5in</MarginTop><MarginLeft>0.5in</MarginLeft><MarginRight>0.5in</MarginRight><MarginBottom>0.5in</MarginBottom></DeviceInfo>";

// Call the export function
// ExportRdlcToPdf(report, "Path/To/Save/YourReport.pdf", deviceInfo);