Hey there! Creating a C# app that generates PDFs and Excel files with tables and headers is totally manageable with the right libraries. I’ll walk you through both tasks with practical code examples so you can hit the ground running.

I’d recommend using iTextSharp (a popular, battle-tested library for PDF generation). If you’re targeting .NET Core/.NET 5+, use the iTextSharp.LGPLv2.Core NuGet package instead for better compatibility.

First, install the appropriate NuGet package:

// For .NET Framework
Install-Package iTextSharp

// For .NET Core/.NET 5+
Install-Package iTextSharp.LGPLv2.Core

To add persistent headers across all pages, you’ll need a custom PageEventHelper to handle header rendering. Here’s a complete example that includes both a header and a formatted table:

using System.IO;
using iTextSharp.text;
using iTextSharp.text.pdf;

public class PdfGenerator
{
    public void GeneratePdf(string outputPath)
    {
        // Initialize a new A4 document with custom margins
        Document document = new Document(PageSize.A4, 50, 50, 70, 70);
        PdfWriter writer = PdfWriter.GetInstance(document, new FileStream(outputPath, FileMode.Create));
        
        // Attach our custom header handler
        writer.PageEvent = new CustomHeaderHandler();
        
        document.Open();
        
        // Add a title to the first page (optional)
        document.Add(new Paragraph("Sample PDF with Table & Persistent Header"));
        document.Add(Chunk.NEWLINE);
        
        // Create a 3-column table that fills the page width
        PdfPTable dataTable = new PdfPTable(3);
        dataTable.WidthPercentage = 100;
        
        // Add bold column headers
        dataTable.AddCell(new Phrase("ID", FontFactory.GetFont(FontFactory.HELVETICA_BOLD)));
        dataTable.AddCell(new Phrase("Full Name", FontFactory.GetFont(FontFactory.HELVETICA_BOLD)));
        dataTable.AddCell(new Phrase("Contact Email", FontFactory.GetFont(FontFactory.HELVETICA_BOLD)));
        
        // Populate table with sample data
        dataTable.AddCell("1");
        dataTable.AddCell("John Doe");
        dataTable.AddCell("john.doe@example.com");
        
        dataTable.AddCell("2");
        dataTable.AddCell("Jane Smith");
        dataTable.AddCell("jane.smith@example.com");
        
        // Add the table to the document
        document.Add(dataTable);
        
        document.Close();
    }
}

// Custom class to render headers on every page
public class CustomHeaderHandler : PdfPageEventHelper
{
    public override void OnEndPage(PdfWriter writer, Document document)
    {
        // Create a single-column table for the header
        PdfPTable headerTable = new PdfPTable(1);
        headerTable.WidthPercentage = 100;
        
        // Add header text with bold styling
        headerTable.AddCell(new Phrase("My Application - Generated Report", FontFactory.GetFont(FontFactory.HELVETICA, 12, Font.BOLD)));
        
        // Position the header at the top of the page (adjust coordinates as needed)
        headerTable.WriteSelectedRows(0, -1, document.LeftMargin, document.Top + 20, writer.DirectContent);
    }
}

This code creates a PDF with a bold header on every page and a clean data table with styled column headers. Tweak margins, fonts, or table sizing to match your app’s design.

For Excel generation, EPPlus is my go-to—it’s intuitive and handles tables and headers seamlessly. Note: EPPlus requires a commercial license for commercial use; if you need a free open-source alternative, check out NPOI.

First, install the EPPlus NuGet package:

Install-Package EPPlus

Here’s an example that generates an Excel file with a centered top header, styled table headers, and an auto-formatted data table:

using System.IO;
using OfficeOpenXml;
using OfficeOpenXml.Style;

public class ExcelGenerator
{
    public void GenerateExcel(string outputPath)
    {
        // Set license context (required for EPPlus v5+)
        ExcelPackage.LicenseContext = LicenseContext.NonCommercial; // Use LicenseContext.Commercial for commercial apps
        
        using (ExcelPackage excelPackage = new ExcelPackage())
        {
            // Create a new worksheet
            ExcelWorksheet worksheet = excelPackage.Workbook.Worksheets.Add("User Data");
            
            // Add a top header (merged across columns)
            worksheet.Cells["A1"].Value = "My Application - User Report";
            worksheet.Cells["A1"].Style.Font.Bold = true;
            worksheet.Cells["A1"].Style.Font.Size = 14;
            worksheet.Cells["A1:C1"].Merge = true;
            worksheet.Cells["A1:C1"].Style.HorizontalAlignment = ExcelHorizontalAlignment.Center;
            
            // Add table column headers (row 3)
            worksheet.Cells["A3"].Value = "ID";
            worksheet.Cells["B3"].Value = "Full Name";
            worksheet.Cells["C3"].Value = "Contact Email";
            
            // Style table headers with gray background and bold text
            var headerRange = worksheet.Cells["A3:C3"];
            headerRange.Style.Font.Bold = true;
            headerRange.Style.Fill.PatternType = ExcelFillStyle.Solid;
            headerRange.Style.Fill.BackgroundColor.SetColor(System.Drawing.Color.LightGray);
            
            // Populate table with sample data
            worksheet.Cells["A4"].Value = 1;
            worksheet.Cells["B4"].Value = "John Doe";
            worksheet.Cells["C4"].Value = "john.doe@example.com";
            
            worksheet.Cells["A5"].Value = 2;
            worksheet.Cells["B5"].Value = "Jane Smith";
            worksheet.Cells["C5"].Value = "jane.smith@example.com";
            
            // Create an official Excel table (adds filtering/sorting out of the box)
            var dataTable = worksheet.Tables.Add(worksheet.Cells["A3:C5"], "UserTable");
            dataTable.TableStyle = TableStyles.Medium2; // Apply a built-in stylish format
            
            // Auto-fit columns to content for better readability
            worksheet.Cells[worksheet.Dimension.Address].AutoFitColumns();
            
            // Save the final Excel file
            excelPackage.SaveAs(new FileInfo(outputPath));
        }
    }
}

This example produces an Excel file with a polished layout: a centered top title, styled column headers, and a formatted data table with built-in styling. Adjust table styles, fonts, or cell merging to fit your needs.

内容的提问来源于stack exchange，提问作者Aleksa Djuric