C#でPDF分割 — 複数ページのPDFを単一ページに分割・PDF変換する方法

using IronPdf;

PdfDocument pdf = PdfDocument.FromFile("multiPage.pdf");

for (int idx = 0; idx < pdf.PageCount; idx++)
{
    // Create new document for each page
    PdfDocument outputDocument = pdf.CopyPage(idx);

    string fileName = @$"multiPage - Page {idx + 1}_tempfile.pdf";

    // Export to new file
    outputDocument.SaveAs(fileName);
}

Imports IronPdf

Private pdf As PdfDocument = PdfDocument.FromFile("multiPage.pdf")

For idx As Integer = 0 To pdf.PageCount - 1
	' Create new document for each page
	Dim outputDocument As PdfDocument = pdf.CopyPage(idx)

	Dim fileName As String = $"multiPage - Page {idx + 1}_tempfile.pdf"

	' Export to new file
	outputDocument.SaveAs(fileName)
Next idx

using IronPdf;
using System;
using System.IO;

public class PdfSplitter
{
    public static void SplitPdfWithValidation(string inputPath, string outputDirectory)
    {
        try
        {
            // Validate input file exists
            if (!File.Exists(inputPath))
            {
                throw new FileNotFoundException("Input PDF file not found.", inputPath);
            }

            // Create output directory if it doesn't exist
            Directory.CreateDirectory(outputDirectory);

            // Load the PDF document
            PdfDocument pdf = PdfDocument.FromFile(inputPath);

            // Get the file name without extension for naming split files
            string baseFileName = Path.GetFileNameWithoutExtension(inputPath);

            Console.WriteLine($"Splitting {pdf.PageCount} pages from {baseFileName}...");

            for (int idx = 0; idx < pdf.PageCount; idx++)
            {
                // Copy individual page
                PdfDocument singlePagePdf = pdf.CopyPage(idx);

                // Create descriptive filename with zero-padding for proper sorting
                string pageNumber = (idx + 1).ToString().PadLeft(3, '0');
                string outputPath = Path.Combine(outputDirectory, $"{baseFileName}_Page_{pageNumber}.pdf");

                // Save the single page PDF
                singlePagePdf.SaveAs(outputPath);

                Console.WriteLine($"Created: {outputPath}");
            }

            Console.WriteLine("PDF splitting completed successfully!");
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Error splitting PDF: {ex.Message}");
            throw;
        }
    }
}

Imports IronPdf
Imports System
Imports System.IO

Public Class PdfSplitter
    Public Shared Sub SplitPdfWithValidation(inputPath As String, outputDirectory As String)
        Try
            ' Validate input file exists
            If Not File.Exists(inputPath) Then
                Throw New FileNotFoundException("Input PDF file not found.", inputPath)
            End If

            ' Create output directory if it doesn't exist
            Directory.CreateDirectory(outputDirectory)

            ' Load the PDF document
            Dim pdf As PdfDocument = PdfDocument.FromFile(inputPath)

            ' Get the file name without extension for naming split files
            Dim baseFileName As String = Path.GetFileNameWithoutExtension(inputPath)

            Console.WriteLine($"Splitting {pdf.PageCount} pages from {baseFileName}...")

            For idx As Integer = 0 To pdf.PageCount - 1
                ' Copy individual page
                Dim singlePagePdf As PdfDocument = pdf.CopyPage(idx)

                ' Create descriptive filename with zero-padding for proper sorting
                Dim pageNumber As String = (idx + 1).ToString().PadLeft(3, "0"c)
                Dim outputPath As String = Path.Combine(outputDirectory, $"{baseFileName}_Page_{pageNumber}.pdf")

                ' Save the single page PDF
                singlePagePdf.SaveAs(outputPath)

                Console.WriteLine($"Created: {outputPath}")
            Next

            Console.WriteLine("PDF splitting completed successfully!")
        Catch ex As Exception
            Console.WriteLine($"Error splitting PDF: {ex.Message}")
            Throw
        End Try
    End Sub
End Class

using IronPdf;
using System.Collections.Generic;

public class MultiPageExtraction
{
    public static void ExtractPageRanges(string inputPath)
    {
        PdfDocument pdf = PdfDocument.FromFile(inputPath);

        // Extract pages 1-5 (0-indexed, so pages 0-4)
        List<int> firstChapter = new List<int> { 0, 1, 2, 3, 4 };
        PdfDocument chapterOne = pdf.CopyPages(firstChapter);
        chapterOne.SaveAs("Chapter_1.pdf");

        // Extract every other page (odd pages)
        List<int> oddPages = new List<int>();
        for (int i = 0; i < pdf.PageCount; i += 2)
        {
            oddPages.Add(i);
        }
        PdfDocument oddPagesDoc = pdf.CopyPages(oddPages);
        oddPagesDoc.SaveAs("Odd_Pages.pdf");

        // Extract specific non-consecutive pages
        List<int> selectedPages = new List<int> { 0, 4, 9, 14 }; // Pages 1, 5, 10, 15
        PdfDocument customSelection = pdf.CopyPages(selectedPages);
        customSelection.SaveAs("Selected_Pages.pdf");
    }
}

Imports IronPdf
Imports System.Collections.Generic

Public Class MultiPageExtraction
    Public Shared Sub ExtractPageRanges(inputPath As String)
        Dim pdf As PdfDocument = PdfDocument.FromFile(inputPath)

        ' Extract pages 1-5 (0-indexed, so pages 0-4)
        Dim firstChapter As New List(Of Integer) From {0, 1, 2, 3, 4}
        Dim chapterOne As PdfDocument = pdf.CopyPages(firstChapter)
        chapterOne.SaveAs("Chapter_1.pdf")

        ' Extract every other page (odd pages)
        Dim oddPages As New List(Of Integer)()
        For i As Integer = 0 To pdf.PageCount - 1 Step 2
            oddPages.Add(i)
        Next
        Dim oddPagesDoc As PdfDocument = pdf.CopyPages(oddPages)
        oddPagesDoc.SaveAs("Odd_Pages.pdf")

        ' Extract specific non-consecutive pages
        Dim selectedPages As New List(Of Integer) From {0, 4, 9, 14} ' Pages 1, 5, 10, 15
        Dim customSelection As PdfDocument = pdf.CopyPages(selectedPages)
        customSelection.SaveAs("Selected_Pages.pdf")
    End Sub
End Class