La comparaison automatisée des documents PDF est essentielle pour suivre les modifications, valider les différentes versions et automatiser les flux de travail d'assurance qualité. Que vous ayez besoin de comparer deux fichiers PDF pour la gestion de documents ou de trouver des différences dans les révisions d'un contrat, IronPDF fournit une solution simplifiée pour comparer des fichiers PDF en C#.
Ce tutoriel explique comment comparer deux documents PDF à l'aide des fonctionnalités d'extraction de texte d'IronPDF, depuis les comparaisons de base jusqu'à la création de rapports de différences détaillés. Vous apprendrez des techniques pratiques avec des exemples de code fonctionnant sur les plateformes Windows, Linux, macOS, Docker et cloud.
Avant de commencer, assurez-vous d'avoir installé :
Installez IronPDF via le gestionnaire de packages NuGet dans votre projet .NET :
Ou en utilisant l'interface de ligne de commande .NET :
Ajoutez la référence de l'espace de noms nécessaire à vos fichiers :
using IronPdf;
using System;Imports IronPdf
Imports System
Commençons par un exemple de code pour comparer des fichiers PDF en extrayant et en comparant leur contenu textuel :
public class BasicPdfComparer
{
public static bool ComparePdfFiles(string firstPdfPath, string secondPdfPath)
{
// Load two PDF documents
var pdf1 = PdfDocument.FromFile(firstPdfPath);
var pdf2 = PdfDocument.FromFile(secondPdfPath);
// Extract all text from both PDFs
string text1 = pdf1.ExtractAllText();
string text2 = pdf2.ExtractAllText();
// Compare the two documents
bool areIdentical = text1 == text2;
// Find differences and calculate similarity
double similarity = CalculateSimilarity(text1, text2);
Console.WriteLine($"Documents are {(areIdentical ? "identical" : "different")}");
Console.WriteLine($"Similarity: {similarity:F2}%");
return areIdentical;
}
private static double CalculateSimilarity(string text1, string text2)
{
if (text1 == text2) return 100.0;
if (string.IsNullOrEmpty(text1) || string.IsNullOrEmpty(text2)) return 0.0;
int matchingChars = 0;
int minLength = Math.Min(text1.Length, text2.Length);
for (int i = 0; i < minLength; i++)
{
if (text1[i] == text2[i]) matchingChars++;
}
return (double)matchingChars / Math.Max(text1.Length, text2.Length) * 100;
}
}Imports System
Public Class BasicPdfComparer
Public Shared Function ComparePdfFiles(firstPdfPath As String, secondPdfPath As String) As Boolean
' Load two PDF documents
Dim pdf1 = PdfDocument.FromFile(firstPdfPath)
Dim pdf2 = PdfDocument.FromFile(secondPdfPath)
' Extract all text from both PDFs
Dim text1 As String = pdf1.ExtractAllText()
Dim text2 As String = pdf2.ExtractAllText()
' Compare the two documents
Dim areIdentical As Boolean = text1 = text2
' Find differences and calculate similarity
Dim similarity As Double = CalculateSimilarity(text1, text2)
Console.WriteLine($"Documents are {(If(areIdentical, "identical", "different"))}")
Console.WriteLine($"Similarity: {similarity:F2}%")
Return areIdentical
End Function
Private Shared Function CalculateSimilarity(text1 As String, text2 As String) As Double
If text1 = text2 Then Return 100.0
If String.IsNullOrEmpty(text1) OrElse String.IsNullOrEmpty(text2) Then Return 0.0
Dim matchingChars As Integer = 0
Dim minLength As Integer = Math.Min(text1.Length, text2.Length)
For i As Integer = 0 To minLength - 1
If text1(i) = text2(i) Then matchingChars += 1
Next
Return matchingChars / Math.Max(text1.Length, text2.Length) * 100
End Function
End ClassCe code charge deux fichiers PDF à l'aide de la méthode PdfDocument.FromFile() d'IronPDF, extrait tout le contenu textuel et effectue une comparaison de chaînes directe. La méthode de comparaison vous fournit des métriques pour identifier à quel point les documents correspondent.
Pour une analyse plus détaillée, comparez deux PDF page par page pour identifier exactement où les différences se produisent :
public static void ComparePageByPage(string firstPdfPath, string secondPdfPath)
{
// Load two files
var pdf1 = PdfDocument.FromFile(firstPdfPath);
var pdf2 = PdfDocument.FromFile(secondPdfPath);
int maxPages = Math.Max(pdf1.PageCount, pdf2.PageCount);
int differencesFound = 0;
for (int i = 0; i < maxPages; i++)
{
// Process each page
string page1Text = i < pdf1.PageCount ? pdf1.ExtractTextFromPage(i) : "";
string page2Text = i < pdf2.PageCount ? pdf2.ExtractTextFromPage(i) : "";
if (page1Text != page2Text)
{
differencesFound++;
Console.WriteLine($"Page {i + 1}: Differences detected");
}
else
{
Console.WriteLine($"Page {i + 1}: Identical");
}
}
Console.WriteLine($"\nSummary: {differencesFound} page(s) with changes");
}Public Shared Sub ComparePageByPage(firstPdfPath As String, secondPdfPath As String)
' Load two files
Dim pdf1 = PdfDocument.FromFile(firstPdfPath)
Dim pdf2 = PdfDocument.FromFile(secondPdfPath)
Dim maxPages As Integer = Math.Max(pdf1.PageCount, pdf2.PageCount)
Dim differencesFound As Integer = 0
For i As Integer = 0 To maxPages - 1
' Process each page
Dim page1Text As String = If(i < pdf1.PageCount, pdf1.ExtractTextFromPage(i), "")
Dim page2Text As String = If(i < pdf2.PageCount, pdf2.ExtractTextFromPage(i), "")
If page1Text <> page2Text Then
differencesFound += 1
Console.WriteLine($"Page {i + 1}: Differences detected")
Else
Console.WriteLine($"Page {i + 1}: Identical")
End If
Next
Console.WriteLine(vbCrLf & $"Summary: {differencesFound} page(s) with changes")
End SubLa méthode ExtractTextFromPage() permet l'extraction ciblée de pages spécifiques. Cette approche aide les développeurs à identifier les divergences entre différentes versions de documents PDF.
Créez une classe de comparateur dédiée pour améliorer votre fonctionnalité de comparaison :
public class PdfComparer
{
private PdfDocument pdf1;
private PdfDocument pdf2;
private bool disposed;
public PdfComparer(string file1Path, string file2Path)
{
// Load the two PDFs
pdf1 = PdfDocument.FromFile(file1Path);
pdf2 = PdfDocument.FromFile(file2Path);
}
public ComparisonResult Compare()
{
var result = new ComparisonResult();
// Compare PDF documents
string text1 = pdf1?.ExtractAllText() ?? string.Empty;
string text2 = pdf2?.ExtractAllText() ?? string.Empty;
result.AreIdentical = string.Equals(text1, text2, StringComparison.Ordinal);
result.SimilarityPercent = CalculateSimilarity(text1, text2);
result.Differences = FindDifferences(text1, text2);
return result;
}
private List<string> FindDifferences(string text1, string text2)
{
var differences = new List<string>();
// Normalize nulls
text1 ??= string.Empty;
text2 ??= string.Empty;
if (string.Equals(text1, text2, StringComparison.Ordinal))
return differences;
// Page-aware comparisons aren't possible here because we only have full-text;
// produce a concise, actionable difference entry:
int min = Math.Min(text1.Length, text2.Length);
int firstDiff = -1;
for (int i = 0; i < min; i++)
{
if (text1[i] != text2[i])
{
firstDiff = i;
break;
}
}
if (firstDiff == -1 && text1.Length != text2.Length)
{
// No differing character in the overlap, but lengths differ
firstDiff = min;
}
// Create short excerpts around the first difference for context
int excerptLength = 200;
string excerpt1 = string.Empty;
string excerpt2 = string.Empty;
if (firstDiff >= 0)
{
int start1 = Math.Max(0, firstDiff);
int len1 = Math.Min(excerptLength, Math.Max(0, text1.Length - start1));
excerpt1 = start1 < text1.Length ? text1.Substring(start1, len1) : string.Empty;
int start2 = Math.Max(0, firstDiff);
int len2 = Math.Min(excerptLength, Math.Max(0, text2.Length - start2));
excerpt2 = start2 < text2.Length ? text2.Substring(start2, len2) : string.Empty;
}
// HTML-encode excerpts if they will be embedded into HTML reports
string safeExcerpt1 = System.Net.WebUtility.HtmlEncode(excerpt1);
string safeExcerpt2 = System.Net.WebUtility.HtmlEncode(excerpt2);
double similarity = CalculateSimilarity(text1, text2);
differences.Add($"Similarity: {similarity:F2}%. Lengths: [{text1.Length}, {text2.Length}]. First difference index: {firstDiff}. Excerpt1: \"{safeExcerpt1}\" Excerpt2: \"{safeExcerpt2}\"");
return differences;
}
public void Close()
{
Dispose();
}
public void Dispose()
{
if (disposed) return;
disposed = true;
pdf1?.Dispose();
pdf2?.Dispose();
}
}
public class ComparisonResult
{
// True when extracted text is exactly the same
public bool AreIdentical { get; set; }
// Similarity expressed as percent (0..100)
public double SimilarityPercent { get; set; }
// Human readable difference entries
public List<string> Differences { get; set; } = new List<string>();
}Imports System
Imports System.Collections.Generic
Imports System.Net
Public Class PdfComparer
Implements IDisposable
Private pdf1 As PdfDocument
Private pdf2 As PdfDocument
Private disposed As Boolean
Public Sub New(file1Path As String, file2Path As String)
' Load the two PDFs
pdf1 = PdfDocument.FromFile(file1Path)
pdf2 = PdfDocument.FromFile(file2Path)
End Sub
Public Function Compare() As ComparisonResult
Dim result As New ComparisonResult()
' Compare PDF documents
Dim text1 As String = If(pdf1?.ExtractAllText(), String.Empty)
Dim text2 As String = If(pdf2?.ExtractAllText(), String.Empty)
result.AreIdentical = String.Equals(text1, text2, StringComparison.Ordinal)
result.SimilarityPercent = CalculateSimilarity(text1, text2)
result.Differences = FindDifferences(text1, text2)
Return result
End Function
Private Function FindDifferences(text1 As String, text2 As String) As List(Of String)
Dim differences As New List(Of String)()
' Normalize nulls
text1 = If(text1, String.Empty)
text2 = If(text2, String.Empty)
If String.Equals(text1, text2, StringComparison.Ordinal) Then
Return differences
End If
' Page-aware comparisons aren't possible here because we only have full-text;
' produce a concise, actionable difference entry:
Dim min As Integer = Math.Min(text1.Length, text2.Length)
Dim firstDiff As Integer = -1
For i As Integer = 0 To min - 1
If text1(i) <> text2(i) Then
firstDiff = i
Exit For
End If
Next
If firstDiff = -1 AndAlso text1.Length <> text2.Length Then
' No differing character in the overlap, but lengths differ
firstDiff = min
End If
' Create short excerpts around the first difference for context
Dim excerptLength As Integer = 200
Dim excerpt1 As String = String.Empty
Dim excerpt2 As String = String.Empty
If firstDiff >= 0 Then
Dim start1 As Integer = Math.Max(0, firstDiff)
Dim len1 As Integer = Math.Min(excerptLength, Math.Max(0, text1.Length - start1))
excerpt1 = If(start1 < text1.Length, text1.Substring(start1, len1), String.Empty)
Dim start2 As Integer = Math.Max(0, firstDiff)
Dim len2 As Integer = Math.Min(excerptLength, Math.Max(0, text2.Length - start2))
excerpt2 = If(start2 < text2.Length, text2.Substring(start2, len2), String.Empty)
End If
' HTML-encode excerpts if they will be embedded into HTML reports
Dim safeExcerpt1 As String = WebUtility.HtmlEncode(excerpt1)
Dim safeExcerpt2 As String = WebUtility.HtmlEncode(excerpt2)
Dim similarity As Double = CalculateSimilarity(text1, text2)
differences.Add($"Similarity: {similarity:F2}%. Lengths: [{text1.Length}, {text2.Length}]. First difference index: {firstDiff}. Excerpt1: ""{safeExcerpt1}"" Excerpt2: ""{safeExcerpt2}""")
Return differences
End Function
Public Sub Close()
Dispose()
End Sub
Public Sub Dispose() Implements IDisposable.Dispose
If disposed Then Return
disposed = True
pdf1?.Dispose()
pdf2?.Dispose()
End Sub
End Class
Public Class ComparisonResult
' True when extracted text is exactly the same
Public Property AreIdentical As Boolean
' Similarity expressed as percent (0..100)
Public Property SimilarityPercent As Double
' Human readable difference entries
Public Property Differences As List(Of String) = New List(Of String)()
End ClassCette structure de classe offre un moyen propre de comparer des documents PDF tout en gérant correctement les objets et références de documents.
Générez un rapport basé sur HTML qui souligne les différences entre deux documents et enregistrez-le sous forme de fichier PDF :
public static void CreateComparisonReport(string pdf1Path, string pdf2Path, string outputPath)
{
// Load PDFs for comparison
var pdf1 = PdfDocument.FromFile(pdf1Path);
var pdf2 = PdfDocument.FromFile(pdf2Path);
// Build HTML report with details
string htmlReport = @"
<html>
<head>
<style>
body { font-family: Arial, sans-serif; margin: 20px; }
.identical { color: green; }
.different { color: red; }
table { width: 100%; border-collapse: collapse; }
th, td { border: 1px solid #ddd; padding: 8px; }
</style>
</head>
<body>
<h1>PDF Comparison Report</h1>
<table>
<tr><th>Page</th><th>Status</th></tr>";
// Process each page
for (int i = 0; i < Math.Max(pdf1.PageCount, pdf2.PageCount); i++)
{
string page1 = i < pdf1.PageCount ? pdf1.ExtractTextFromPage(i) : "";
string page2 = i < pdf2.PageCount ? pdf2.ExtractTextFromPage(i) : "";
bool identical = page1 == page2;
string status = identical ? "Identical" : "Different";
htmlReport += $"<tr><td>Page {i + 1}</td><td class='{status.ToLower()}'>{status}</td></tr>";
}
htmlReport += "</table></body></html>";
// Create and save the report
var renderer = new ChromePdfRenderer();
var reportPdf = renderer.RenderHtmlAsPdf(htmlReport);
reportPdf.SaveAs(outputPath);
Console.WriteLine($"Report saved to: {outputPath}");
}Imports System
Public Shared Sub CreateComparisonReport(pdf1Path As String, pdf2Path As String, outputPath As String)
' Load PDFs for comparison
Dim pdf1 = PdfDocument.FromFile(pdf1Path)
Dim pdf2 = PdfDocument.FromFile(pdf2Path)
' Build HTML report with details
Dim htmlReport As String = "
<html>
<head>
<style>
body { font-family: Arial, sans-serif; margin: 20px; }
.identical { color: green; }
.different { color: red; }
table { width: 100%; border-collapse: collapse; }
th, td { border: 1px solid #ddd; padding: 8px; }
</style>
</head>
<body>
<h1>PDF Comparison Report</h1>
<table>
<tr><th>Page</th><th>Status</th></tr>"
' Process each page
For i As Integer = 0 To Math.Max(pdf1.PageCount, pdf2.PageCount) - 1
Dim page1 As String = If(i < pdf1.PageCount, pdf1.ExtractTextFromPage(i), "")
Dim page2 As String = If(i < pdf2.PageCount, pdf2.ExtractTextFromPage(i), "")
Dim identical As Boolean = page1 = page2
Dim status As String = If(identical, "Identical", "Different")
htmlReport &= $"<tr><td>Page {i + 1}</td><td class='{status.ToLower()}'>{status}</td></tr>"
Next
htmlReport &= "</table></body></html>"
' Create and save the report
Dim renderer = New ChromePdfRenderer()
Dim reportPdf = renderer.RenderHtmlAsPdf(htmlReport)
reportPdf.SaveAs(outputPath)
Console.WriteLine($"Report saved to: {outputPath}")
End SubCe code montre comment créer un document PDF professionnel avec les résultats de la comparaison. Le rapport est enregistré dans le chemin spécifié.
Lorsque vous devez comparer plusieurs documents PDF simultanément, utilisez cette méthode :
public static void CompareMultiplePdfs(params string[] pdfPaths)
{
if (pdfPaths.Length < 2)
{
Console.WriteLine("Need at least two files to compare");
return;
}
// Load multiple PDF documents
var pdfs = new List<PdfDocument>();
foreach (var path in pdfPaths)
{
pdfs.Add(PdfDocument.FromFile(path));
}
// Compare all documents
for (int i = 0; i < pdfs.Count - 1; i++)
{
for (int j = i + 1; j < pdfs.Count; j++)
{
string text1 = pdfs[i].ExtractAllText();
string text2 = pdfs[j].ExtractAllText();
bool identical = text1 == text2;
Console.WriteLine($"File {i+1} vs File {j+1}: {(identical ? "Identical" : "Different")}");
}
}
// Close all documents
pdfs.ForEach(pdf => pdf.Dispose());
}Imports System
Imports System.Collections.Generic
Public Shared Sub CompareMultiplePdfs(ParamArray pdfPaths As String())
If pdfPaths.Length < 2 Then
Console.WriteLine("Need at least two files to compare")
Return
End If
' Load multiple PDF documents
Dim pdfs As New List(Of PdfDocument)()
For Each path As String In pdfPaths
pdfs.Add(PdfDocument.FromFile(path))
Next
' Compare all documents
For i As Integer = 0 To pdfs.Count - 2
For j As Integer = i + 1 To pdfs.Count - 1
Dim text1 As String = pdfs(i).ExtractAllText()
Dim text2 As String = pdfs(j).ExtractAllText()
Dim identical As Boolean = text1 = text2
Console.WriteLine($"File {i + 1} vs File {j + 1}: {(If(identical, "Identical", "Different"))}")
Next
Next
' Close all documents
pdfs.ForEach(Sub(pdf) pdf.Dispose())
End SubCette approche permet de comparer plusieurs documents PDF en une seule exécution, utile pour les besoins de traitement par lots.
Voici un exemple pratique de suivi des révisions dans des documents juridiques :
public class ContractVersionControl
{
public static void CompareContractVersions(string originalPath, string revisedPath)
{
// System for comparing contract versions
Console.WriteLine("Contract Version Comparison System");
var original = PdfDocument.FromFile(originalPath);
var revised = PdfDocument.FromFile(revisedPath);
// Extract contract contents
string originalText = original.ExtractAllText();
string revisedText = revised.ExtractAllText();
if (originalText == revisedText)
{
Console.WriteLine("No changes detected");
}
else
{
Console.WriteLine("Changes detected in revised version");
// Create detailed report
string reportPath = $"contract_comparison_{DateTime.Now:yyyyMMdd}.pdf";
CreateComparisonReport(originalPath, revisedPath, reportPath);
Console.WriteLine($"Report created: {reportPath}");
}
// Close documents
original.Dispose();
revised.Dispose();
}
}Public Class ContractVersionControl
Public Shared Sub CompareContractVersions(originalPath As String, revisedPath As String)
' System for comparing contract versions
Console.WriteLine("Contract Version Comparison System")
Dim original = PdfDocument.FromFile(originalPath)
Dim revised = PdfDocument.FromFile(revisedPath)
' Extract contract contents
Dim originalText As String = original.ExtractAllText()
Dim revisedText As String = revised.ExtractAllText()
If originalText = revisedText Then
Console.WriteLine("No changes detected")
Else
Console.WriteLine("Changes detected in revised version")
' Create detailed report
Dim reportPath As String = $"contract_comparison_{DateTime.Now:yyyyMMdd}.pdf"
CreateComparisonReport(originalPath, revisedPath, reportPath)
Console.WriteLine($"Report created: {reportPath}")
End If
' Close documents
original.Dispose()
revised.Dispose()
End Sub
End ClassCela montre comment comparer deux versions d'un contrat PDF et générer des rapports pour révision. Le système détecte automatiquement les changements et crée la documentation.
IronPDF gère en toute transparence les fichiers PDF chiffrés en passant le mot de passe lors de l'appel à la méthode de chargement :
public static bool CompareProtectedPdfs(string pdf1Path, string pass1,
string pdf2Path, string pass2)
{
// Load password-protected two PDFs
var pdf1 = PdfDocument.FromFile(pdf1Path, pass1);
var pdf2 = PdfDocument.FromFile(pdf2Path, pass2);
// Extract and compare text
string text1 = pdf1.ExtractAllText();
string text2 = pdf2.ExtractAllText();
bool result = text1 == text2;
// Close and dispose
pdf1.Dispose();
pdf2.Dispose();
return result;
}Public Shared Function CompareProtectedPdfs(pdf1Path As String, pass1 As String, pdf2Path As String, pass2 As String) As Boolean
' Load password-protected two PDFs
Dim pdf1 = PdfDocument.FromFile(pdf1Path, pass1)
Dim pdf2 = PdfDocument.FromFile(pdf2Path, pass2)
' Extract and compare text
Dim text1 As String = pdf1.ExtractAllText()
Dim text2 As String = pdf2.ExtractAllText()
Dim result As Boolean = text1 = text2
' Close and dispose
pdf1.Dispose()
pdf2.Dispose()
Return result
End FunctionIl suffit de passer le paramètre de mot de passe lors du chargement de PDFs protégés. IronPDF gère automatiquement le déchiffrement.
Suivez ces étapes pour implémenter la comparaison PDF dans votre projet .NET :
PdfDocument pour chaque fichierExtractAllText() pour obtenir le contenu
Pour utiliser IronPDF sans filigranes, définissez votre clé de licence :
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY"Consultez la page relative aux licences pour obtenir des informations détaillées sur les options disponibles. Téléchargez la version d'essai gratuite d'IronPDF et configurez vos fichiers PDF en utilisant des fonctionnalités de comparaison de qualité professionnelle.
IronPDF simplifie le processus de comparaison de deux fichiers PDF en utilisant C# avec son API intuitive et ses puissantes capacités d'extraction. De la comparaison de base à la création de rapports détaillés, IronPDF fournit tous les outils nécessaires pour des flux de travail de comparaison de documents robustes.
La combinaison d'une installation facile, de fonctionnalités complètes et d'un support multiplateforme fait d'IronPDF le choix idéal pour les développeurs implémentant la comparaison PDF dans les applications .NET. Que vous développiez des systèmes de gestion de documents ou des solutions de contrôle de version, l'approche simple d'IronPDF vous permet de démarrer rapidement.
Démarrez votre essai gratuit d'IronPDF dès aujourd'hui et profitez de ses fonctionnalités professionnelles de comparaison de PDF. Avec un support technique complet et une documentation approfondie, vous disposerez de fonctionnalités prêtes pour la production en quelques heures. Consultez la documentation complète pour en savoir plus sur les fonctionnalités avancées.
Curtis Chau détient un baccalauréat en informatique (Université de Carleton) et se spécialise dans le développement front-end avec expertise en Node.js, TypeScript, JavaScript et React. Passionné par la création d'interfaces utilisateur intuitives et esthétiquement plaisantes, Curtis aime travailler avec des frameworks modernes et créer des manuels bien structurés et visuellement attrayants.
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