C# PDF库

HTML到PDF

using IronPdf;

// Disable local disk access or cross-origin requests
Installation.EnableWebSecurity = true;

// Instantiate Renderer
var renderer = new ChromePdfRenderer();

// Create a PDF from a HTML string using C#
var pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1>");

// Export to a file or Stream
pdf.SaveAs("output.pdf");

// Advanced Example with HTML Assets
// Load external html assets: Images, CSS and JavaScript.
// An optional BasePath 'C:\site\assets\' is set as the file location to load assets from
var myAdvancedPdf = renderer.RenderHtmlAsPdf("<img src='icons/iron.png'>", @"C:\site\assets\");
myAdvancedPdf.SaveAs("html-with-assets.pdf");

using IronPdf;

// Disable local disk access or cross-origin requests
Installation.EnableWebSecurity = true;

// Instantiate Renderer
var renderer = new ChromePdfRenderer();

// Create a PDF from a HTML string using C#
var pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1>");

// Export to a file or Stream
pdf.SaveAs("output.pdf");

// Advanced Example with HTML Assets
// Load external html assets: Images, CSS and JavaScript.
// An optional BasePath 'C:\site\assets\' is set as the file location to load assets from
var myAdvancedPdf = renderer.RenderHtmlAsPdf("<img src='icons/iron.png'>", @"C:\site\assets\");
myAdvancedPdf.SaveAs("html-with-assets.pdf");

PM >Install-Package IronPdf

Install-Package IronPdf

视频

如何使用C#将HTML转换为具有响应式CSS的PDF

Curtis Chau

Updated: 2026年5月18日

虽然ComPDFKit提供了可靠的 PDF 操作功能，但有几个因素促使开发团队考虑更成熟的替代方案。

市场成熟度和生态系统比较

ComPDFKit 面临着新进入市场者共同面临的挑战：文档空白、社区规模较小、Stack Overflow 覆盖范围有限。IronPDF十年的精进提供了企业项目所需的稳定性和资源。

方面	ComPDFKit	IronPDF
HTML-to-PDF	需要手动解析 HTML	原生 Chromium 渲染
市场成熟度	新加入者	10 年以上，久经考验
社区规模	规模较小、有限的 Stack Overflow	庞大、活跃的社区
文档	一些差距	广泛的教程和指南
下载	成长性	1000 多万次 NuGet 下载
API 风格	受 C++ 影响，冗长	现代.NET流畅的应用程序接口
内存管理	手动 `Release()` 调用	自动 GC 处理

功能对等

这两个库都支持全面的 PDF 功能：

特征	ComPDFKit	IronPDF
HTML 至 PDF	基础/手册	✅ 原生 Chromium
URL 至 PDF	手册实施	✅ 内置
从零开始创建 PDF	✅	✅
PDF 编辑	✅	✅
文本提取	✅	✅
合并/拆分	✅	✅
数字签名	✅	✅
表格填写	✅	✅
水印	✅	✅
跨平台	Windows、Linux、macOS	Windows、Linux、macOS

主要迁移优势

1.**出色的 HTML 渲染：**IronPDF的 Chromium 引擎原生支持现代 CSS3、JavaScript 和响应式布局。 2.**成熟的生态系统：**经过 10 年以上的完善、详尽的文档记录和久经考验的稳定性 3. 更简洁的API： 少样板代码，不需要手动内存管理，使用 Release() 调用 4.**更佳的 .NET 集成：**原生 async/await、LINQ 支持、流畅接口 5.**丰富的资源：**数以千计的 Stack Overflow 答案和社区示例

迁移前准备

前提条件

确保您的环境符合这些要求：

.NET Framework 4.6.2+ 或 .NET Core 3.1 / .NET 5-9
Visual Studio 2019+ 或带有 C# 扩展的 VS Code
访问 NuGet 包管理器 -IronPDF许可证密钥（可在ironpdf.com免费试用）

审核ComPDFKit的使用情况

在您的解决方案目录中运行这些命令，以识别所有ComPDFKit引用：

# Find allComPDFKitusages in your codebase
grep -r "using ComPDFKit" --include="*.cs" .
grep -r "CPDFDocument\|CPDFPage\|CPDFAnnotation" --include="*.cs" .

# Find NuGet package references
grep -r "ComPDFKit" --include="*.csproj" .

# Find allComPDFKitusages in your codebase
grep -r "using ComPDFKit" --include="*.cs" .
grep -r "CPDFDocument\|CPDFPage\|CPDFAnnotation" --include="*.cs" .

# Find NuGet package references
grep -r "ComPDFKit" --include="*.csproj" .

SHELL

值得期待的重大变化

变更	ComPDFKit	IronPDF	影响
文档加载	`CPDFDocument.InitWithFilePath()`	`PdfDocument.FromFile()`	方法名称更改
节约	`document.WriteToFilePath()`	`pdf.SaveAs()`	方法名称更改
内存清理	`document.Release()` 必需	自动 (GC)	删除手动清理
页面访问	`document.PageAtIndex(i)`	`pdf.Pages[i]`	数组式访问
页面索引	基于 0	基于 0	无需改动
HTML 渲染	手册实施	`RenderHtmlAsPdf()`	主要简化
文本提取	`textPage.GetText()`	`pdf.ExtractAllText()`	简化 API

逐步迁移过程

步骤 1：更新 NuGet 软件包

移除ComPDFKit软件包并安装 IronPDF：

# RemoveComPDFKitpackages
dotnet remove package ComPDFKit.NetCore
dotnet remove package ComPDFKit.NetFramework

# Install IronPDF
dotnet add package IronPdf

# RemoveComPDFKitpackages
dotnet remove package ComPDFKit.NetCore
dotnet remove package ComPDFKit.NetFramework

# Install IronPDF
dotnet add package IronPdf

SHELL

步骤 2：更新命名空间引用

用IronPDF替换ComPDFKit命名空间：

// Remove these
using ComPDFKit.PDFDocument;
using ComPDFKit.PDFPage;
using ComPDFKit.PDFAnnotation;
using ComPDFKit.Import;

// Add this
using IronPdf;

// Remove these
using ComPDFKit.PDFDocument;
using ComPDFKit.PDFPage;
using ComPDFKit.PDFAnnotation;
using ComPDFKit.Import;

// Add this
using IronPdf;

Imports IronPdf

Imports IronPdf

步骤 3：配置许可证

// Add at application startup (Program.cs or Global.asax)
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

// Add at application startup (Program.cs or Global.asax)
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

' Add at application startup (Program.vb or Global.asax)
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY"

' Add at application startup (Program.vb or Global.asax)
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY"

完整的 API 迁移参考

文档操作

任务	ComPDFKit	IronPDF
创建空文档	`CPDFDocument.CreateDocument()`	`new PdfDocument()`
从文件加载	`CPDFDocument.InitWithFilePath(path)`	`PdfDocument.FromFile(path)`
从流加载	`CPDFDocument.InitWithStream(stream)`	`PdfDocument.FromStream(stream)`
保存到文件	`document.WriteToFilePath(path)`	`pdf.SaveAs(path)`
获取页数	`document.PageCount`	`pdf.PageCount`
发布/处置	`document.Release()`	不要求

HTML 到 PDF 转换

任务	ComPDFKit	IronPDF
HTML 字符串到 PDF	需要手动执行	`renderer.RenderHtmlAsPdf(html)`
HTML 文件到 PDF	需要手动执行	`renderer.RenderHtmlFileAsPdf(path)`
URL 至 PDF	需要手动执行	`renderer.RenderUrlAsPdf(url)`
设置页面大小	通过页面创建参数	`renderer.RenderingOptions.PaperSize`
设置页边距	通过编辑器配置	`renderer.RenderingOptions.MarginTop` 等

合并和拆分操作

任务	ComPDFKit	IronPDF
合并文件	`doc1.ImportPagesAtIndex(doc2, range, index)`	`PdfDocument.Merge(pdf1, pdf2)`
拆分文件	提取页面到新文档	`pdf.CopyPages(start, end)`

代码迁移示例

HTML 到 PDF 转换

ComPDFKit 和IronPDF的最大区别在于 HTML 渲染。ComPDFKit需要手动放置文本，而IronPDF则使用其 Chromium 引擎原生渲染 HTML。

ComPDFKit实现：

// NuGet: Install-Package ComPDFKit.NetCore
using ComPDFKit.PDFDocument;
using System;

class Program
{
    static void Main()
    {
        // ComPDFKit's .NET SDK has no native HTML-to-PDF rendering.
        // The closest equivalent is to create a blank document and lay
        // out primitives manually, or call ComPDFKit's separate cloud
        // Conversion API (a different SKU).
        var document = CPDFDocument.CreateDocument();
        document.InsertPage(0, 595, 842, string.Empty);

        document.WriteToFilePath("output.pdf");
        document.Release();
    }
}

// NuGet: Install-Package ComPDFKit.NetCore
using ComPDFKit.PDFDocument;
using System;

class Program
{
    static void Main()
    {
        // ComPDFKit's .NET SDK has no native HTML-to-PDF rendering.
        // The closest equivalent is to create a blank document and lay
        // out primitives manually, or call ComPDFKit's separate cloud
        // Conversion API (a different SKU).
        var document = CPDFDocument.CreateDocument();
        document.InsertPage(0, 595, 842, string.Empty);

        document.WriteToFilePath("output.pdf");
        document.Release();
    }
}

Imports ComPDFKit.PDFDocument
Imports System

Module Program
    Sub Main()
        ' ComPDFKit's .NET SDK has no native HTML-to-PDF rendering.
        ' The closest equivalent is to create a blank document and lay
        ' out primitives manually, or call ComPDFKit's separate cloud
        ' Conversion API (a different SKU).
        Dim document = CPDFDocument.CreateDocument()
        document.InsertPage(0, 595, 842, String.Empty)

        document.WriteToFilePath("output.pdf")
        document.Release()
    End Sub
End Module

Imports ComPDFKit.PDFDocument
Imports System

Module Program
    Sub Main()
        ' ComPDFKit's .NET SDK has no native HTML-to-PDF rendering.
        ' The closest equivalent is to create a blank document and lay
        ' out primitives manually, or call ComPDFKit's separate cloud
        ' Conversion API (a different SKU).
        Dim document = CPDFDocument.CreateDocument()
        document.InsertPage(0, 595, 842, String.Empty)

        document.WriteToFilePath("output.pdf")
        document.Release()
    End Sub
End Module

IronPDF 实现：

// NuGet: Install-Package IronPdf
using IronPdf;
using System;

class Program
{
    static void Main()
    {
        var renderer = new ChromePdfRenderer();
        var pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1><p>This is HTML content.</p>");
        pdf.SaveAs("output.pdf");
    }
}

// NuGet: Install-Package IronPdf
using IronPdf;
using System;

class Program
{
    static void Main()
    {
        var renderer = new ChromePdfRenderer();
        var pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1><p>This is HTML content.</p>");
        pdf.SaveAs("output.pdf");
    }
}

Imports IronPdf
Imports System

Class Program
    Shared Sub Main()
        Dim renderer = New ChromePdfRenderer()
        Dim pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1><p>This is HTML content.</p>")
        pdf.SaveAs("output.pdf")
    End Sub
End Class

Imports IronPdf
Imports System

Class Program
    Shared Sub Main()
        Dim renderer = New ChromePdfRenderer()
        Dim pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1><p>This is HTML content.</p>")
        pdf.SaveAs("output.pdf")
    End Sub
End Class

IronPDF的 ChromePdfRenderer 消除了手动文本定位和编辑器管理的需要。有关更多 HTML 转换选项，请参阅 HTML 转 PDF 文档。

合并多个 PDF 文件

ComPDFKit实现：

// NuGet: Install-Package ComPDFKit.NetCore
using ComPDFKit.PDFDocument;
using ComPDFKit.Import;
using System;

class Program
{
    static void Main()
    {
        var document1 = CPDFDocument.InitWithFilePath("file1.pdf");
        var document2 = CPDFDocument.InitWithFilePath("file2.pdf");
        
        // Import pages from document2 into document1
        document1.ImportPagesAtIndex(document2, "0-" + (document2.PageCount - 1), document1.PageCount);
        
        document1.WriteToFilePath("merged.pdf");
        document1.Release();
        document2.Release();
    }
}

// NuGet: Install-Package ComPDFKit.NetCore
using ComPDFKit.PDFDocument;
using ComPDFKit.Import;
using System;

class Program
{
    static void Main()
    {
        var document1 = CPDFDocument.InitWithFilePath("file1.pdf");
        var document2 = CPDFDocument.InitWithFilePath("file2.pdf");
        
        // Import pages from document2 into document1
        document1.ImportPagesAtIndex(document2, "0-" + (document2.PageCount - 1), document1.PageCount);
        
        document1.WriteToFilePath("merged.pdf");
        document1.Release();
        document2.Release();
    }
}

' NuGet: Install-Package ComPDFKit.NetCore
Imports ComPDFKit.PDFDocument
Imports ComPDFKit.Import
Imports System

Module Program
    Sub Main()
        Dim document1 = CPDFDocument.InitWithFilePath("file1.pdf")
        Dim document2 = CPDFDocument.InitWithFilePath("file2.pdf")
        
        ' Import pages from document2 into document1
        document1.ImportPagesAtIndex(document2, "0-" & (document2.PageCount - 1).ToString(), document1.PageCount)
        
        document1.WriteToFilePath("merged.pdf")
        document1.Release()
        document2.Release()
    End Sub
End Module

' NuGet: Install-Package ComPDFKit.NetCore
Imports ComPDFKit.PDFDocument
Imports ComPDFKit.Import
Imports System

Module Program
    Sub Main()
        Dim document1 = CPDFDocument.InitWithFilePath("file1.pdf")
        Dim document2 = CPDFDocument.InitWithFilePath("file2.pdf")
        
        ' Import pages from document2 into document1
        document1.ImportPagesAtIndex(document2, "0-" & (document2.PageCount - 1).ToString(), document1.PageCount)
        
        document1.WriteToFilePath("merged.pdf")
        document1.Release()
        document2.Release()
    End Sub
End Module

IronPDF 实现：

// NuGet: Install-Package IronPdf
using IronPdf;
using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        var pdf1 = PdfDocument.FromFile("file1.pdf");
        var pdf2 = PdfDocument.FromFile("file2.pdf");
        
        var merged = PdfDocument.Merge(new List<PdfDocument> { pdf1, pdf2 });
        merged.SaveAs("merged.pdf");
    }
}

// NuGet: Install-Package IronPdf
using IronPdf;
using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        var pdf1 = PdfDocument.FromFile("file1.pdf");
        var pdf2 = PdfDocument.FromFile("file2.pdf");
        
        var merged = PdfDocument.Merge(new List<PdfDocument> { pdf1, pdf2 });
        merged.SaveAs("merged.pdf");
    }
}

' NuGet: Install-Package IronPdf
Imports IronPdf
Imports System
Imports System.Collections.Generic

Module Program
    Sub Main()
        Dim pdf1 = PdfDocument.FromFile("file1.pdf")
        Dim pdf2 = PdfDocument.FromFile("file2.pdf")

        Dim merged = PdfDocument.Merge(New List(Of PdfDocument) From {pdf1, pdf2})
        merged.SaveAs("merged.pdf")
    End Sub
End Module

' NuGet: Install-Package IronPdf
Imports IronPdf
Imports System
Imports System.Collections.Generic

Module Program
    Sub Main()
        Dim pdf1 = PdfDocument.FromFile("file1.pdf")
        Dim pdf2 = PdfDocument.FromFile("file2.pdf")

        Dim merged = PdfDocument.Merge(New List(Of PdfDocument) From {pdf1, pdf2})
        merged.SaveAs("merged.pdf")
    End Sub
End Module

IronPDF的静态 Merge 方法消除了使用页面范围字符串的冗长 ImportPagesAtIndex 模式。更多选项请参阅PDF 合并文档。

添加水印

水印显示了ComPDFKit的属性驱动 CPDFWatermark 配置与IronPDF基于HTML的样式化之间的差异。

ComPDFKit实现：

// NuGet: Install-Package ComPDFKit.NetCore
using ComPDFKit.PDFDocument;
using ComPDFKit.PDFWatermark;
using System;

class Program
{
    static void Main()
    {
        var document = CPDFDocument.InitWithFilePath("input.pdf");

        CPDFWatermark watermark = document.InitWatermark(
            C_Watermark_Type.WATERMARK_TYPE_TEXT);
        watermark.SetText("CONFIDENTIAL");
        watermark.SetFontName("Helvetica");
        watermark.SetFontSize(48);
        watermark.SetTextRGBColor(255, 0, 0);
        watermark.SetRotation(45);
        watermark.SetOpacity(76); // 0..255
        watermark.SetVertalign(C_Watermark_Vertalign.WATERMARK_VERTALIGN_CENTER);
        watermark.SetHorizalign(C_Watermark_Horizalign.WATERMARK_HORIZALIGN_CENTER);
        watermark.SetPages($"0-{document.PageCount - 1}");
        watermark.SetFront(true);
        watermark.CreateWatermark();

        document.WriteToFilePath("watermarked.pdf");
        document.Release();
    }
}

// NuGet: Install-Package ComPDFKit.NetCore
using ComPDFKit.PDFDocument;
using ComPDFKit.PDFWatermark;
using System;

class Program
{
    static void Main()
    {
        var document = CPDFDocument.InitWithFilePath("input.pdf");

        CPDFWatermark watermark = document.InitWatermark(
            C_Watermark_Type.WATERMARK_TYPE_TEXT);
        watermark.SetText("CONFIDENTIAL");
        watermark.SetFontName("Helvetica");
        watermark.SetFontSize(48);
        watermark.SetTextRGBColor(255, 0, 0);
        watermark.SetRotation(45);
        watermark.SetOpacity(76); // 0..255
        watermark.SetVertalign(C_Watermark_Vertalign.WATERMARK_VERTALIGN_CENTER);
        watermark.SetHorizalign(C_Watermark_Horizalign.WATERMARK_HORIZALIGN_CENTER);
        watermark.SetPages($"0-{document.PageCount - 1}");
        watermark.SetFront(true);
        watermark.CreateWatermark();

        document.WriteToFilePath("watermarked.pdf");
        document.Release();
    }
}

Imports ComPDFKit.PDFDocument
Imports ComPDFKit.PDFWatermark
Imports System

Class Program
    Shared Sub Main()
        Dim document = CPDFDocument.InitWithFilePath("input.pdf")

        Dim watermark As CPDFWatermark = document.InitWatermark(C_Watermark_Type.WATERMARK_TYPE_TEXT)
        watermark.SetText("CONFIDENTIAL")
        watermark.SetFontName("Helvetica")
        watermark.SetFontSize(48)
        watermark.SetTextRGBColor(255, 0, 0)
        watermark.SetRotation(45)
        watermark.SetOpacity(76) ' 0..255
        watermark.SetVertalign(C_Watermark_Vertalign.WATERMARK_VERTALIGN_CENTER)
        watermark.SetHorizalign(C_Watermark_Horizalign.WATERMARK_HORIZALIGN_CENTER)
        watermark.SetPages($"0-{document.PageCount - 1}")
        watermark.SetFront(True)
        watermark.CreateWatermark()

        document.WriteToFilePath("watermarked.pdf")
        document.Release()
    End Sub
End Class

Imports ComPDFKit.PDFDocument
Imports ComPDFKit.PDFWatermark
Imports System

Class Program
    Shared Sub Main()
        Dim document = CPDFDocument.InitWithFilePath("input.pdf")

        Dim watermark As CPDFWatermark = document.InitWatermark(C_Watermark_Type.WATERMARK_TYPE_TEXT)
        watermark.SetText("CONFIDENTIAL")
        watermark.SetFontName("Helvetica")
        watermark.SetFontSize(48)
        watermark.SetTextRGBColor(255, 0, 0)
        watermark.SetRotation(45)
        watermark.SetOpacity(76) ' 0..255
        watermark.SetVertalign(C_Watermark_Vertalign.WATERMARK_VERTALIGN_CENTER)
        watermark.SetHorizalign(C_Watermark_Horizalign.WATERMARK_HORIZALIGN_CENTER)
        watermark.SetPages($"0-{document.PageCount - 1}")
        watermark.SetFront(True)
        watermark.CreateWatermark()

        document.WriteToFilePath("watermarked.pdf")
        document.Release()
    End Sub
End Class

IronPDF 实现：

// NuGet: Install-Package IronPdf
using IronPdf;
using IronPdf.Editing;
using System;

class Program
{
    static void Main()
    {
        var pdf = PdfDocument.FromFile("input.pdf");
        
        pdf.ApplyWatermark("<h1 style='color:rgba(255,0,0,0.3);'>CONFIDENTIAL</h1>",
            rotation: 45,
            verticalAlignment: VerticalAlignment.Middle,
            horizontalAlignment: HorizontalAlignment.Center);
        
        pdf.SaveAs("watermarked.pdf");
    }
}

// NuGet: Install-Package IronPdf
using IronPdf;
using IronPdf.Editing;
using System;

class Program
{
    static void Main()
    {
        var pdf = PdfDocument.FromFile("input.pdf");
        
        pdf.ApplyWatermark("<h1 style='color:rgba(255,0,0,0.3);'>CONFIDENTIAL</h1>",
            rotation: 45,
            verticalAlignment: VerticalAlignment.Middle,
            horizontalAlignment: HorizontalAlignment.Center);
        
        pdf.SaveAs("watermarked.pdf");
    }
}

' NuGet: Install-Package IronPdf
Imports IronPdf
Imports IronPdf.Editing
Imports System

Module Program
    Sub Main()
        Dim pdf = PdfDocument.FromFile("input.pdf")
        
        pdf.ApplyWatermark("<h1 style='color:rgba(255,0,0,0.3);'>CONFIDENTIAL</h1>", 
                           rotation:=45, 
                           verticalAlignment:=VerticalAlignment.Middle, 
                           horizontalAlignment:=HorizontalAlignment.Center)
        
        pdf.SaveAs("watermarked.pdf")
    End Sub
End Module

' NuGet: Install-Package IronPdf
Imports IronPdf
Imports IronPdf.Editing
Imports System

Module Program
    Sub Main()
        Dim pdf = PdfDocument.FromFile("input.pdf")
        
        pdf.ApplyWatermark("<h1 style='color:rgba(255,0,0,0.3);'>CONFIDENTIAL</h1>", 
                           rotation:=45, 
                           verticalAlignment:=VerticalAlignment.Middle, 
                           horizontalAlignment:=HorizontalAlignment.Center)
        
        pdf.SaveAs("watermarked.pdf")
    End Sub
End Module

IronPDF将多步 CPDFWatermark 配置简化为一个带有HTML/CSS样式的方法调用。更多选项请参见水印文档。

文本提取

ComPDFKit实现：

using ComPDFKit.PDFDocument;
using System.Text;

var document = CPDFDocument.InitWithFilePath("document.pdf");

// Extract text (verbose)
var allText = new StringBuilder();
for (int i = 0; i < document.PageCount; i++)
{
    var page = document.PageAtIndex(i);
    var textPage = page.GetTextPage();
    allText.AppendLine(textPage.GetText(0, textPage.CountChars()));
    textPage.Release();
    page.Release();
}

document.WriteToFilePath("output.pdf");
document.Release(); // Must remember to release!

using ComPDFKit.PDFDocument;
using System.Text;

var document = CPDFDocument.InitWithFilePath("document.pdf");

// Extract text (verbose)
var allText = new StringBuilder();
for (int i = 0; i < document.PageCount; i++)
{
    var page = document.PageAtIndex(i);
    var textPage = page.GetTextPage();
    allText.AppendLine(textPage.GetText(0, textPage.CountChars()));
    textPage.Release();
    page.Release();
}

document.WriteToFilePath("output.pdf");
document.Release(); // Must remember to release!

Imports ComPDFKit.PDFDocument
Imports System.Text

Dim document = CPDFDocument.InitWithFilePath("document.pdf")

' Extract text (verbose)
Dim allText As New StringBuilder()
For i As Integer = 0 To document.PageCount - 1
    Dim page = document.PageAtIndex(i)
    Dim textPage = page.GetTextPage()
    allText.AppendLine(textPage.GetText(0, textPage.CountChars()))
    textPage.Release()
    page.Release()
Next

document.WriteToFilePath("output.pdf")
document.Release() ' Must remember to release!

Imports ComPDFKit.PDFDocument
Imports System.Text

Dim document = CPDFDocument.InitWithFilePath("document.pdf")

' Extract text (verbose)
Dim allText As New StringBuilder()
For i As Integer = 0 To document.PageCount - 1
    Dim page = document.PageAtIndex(i)
    Dim textPage = page.GetTextPage()
    allText.AppendLine(textPage.GetText(0, textPage.CountChars()))
    textPage.Release()
    page.Release()
Next

document.WriteToFilePath("output.pdf")
document.Release() ' Must remember to release!

IronPDF 实现：

using IronPdf;

var pdf = PdfDocument.FromFile("document.pdf");

// Extract text (one-liner)
string allText = pdf.ExtractAllText();

pdf.SaveAs("output.pdf");
// No Release() needed - GC handles cleanup

using IronPdf;

var pdf = PdfDocument.FromFile("document.pdf");

// Extract text (one-liner)
string allText = pdf.ExtractAllText();

pdf.SaveAs("output.pdf");
// No Release() needed - GC handles cleanup

Imports IronPdf

Dim pdf = PdfDocument.FromFile("document.pdf")

' Extract text (one-liner)
Dim allText As String = pdf.ExtractAllText()

pdf.SaveAs("output.pdf")
' No Release() needed - GC handles cleanup

Imports IronPdf

Dim pdf = PdfDocument.FromFile("document.pdf")

' Extract text (one-liner)
Dim allText As String = pdf.ExtractAllText()

pdf.SaveAs("output.pdf")
' No Release() needed - GC handles cleanup

IronPDF将多行文本提取与手动 Release() 调用简化为一个单独的方法。有关更多提取选项，请参阅文本提取文档。

密码保护

IronPDF 实现：

using IronPdf;

var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf("<h1>Confidential Document</h1>");

// Set security
pdf.SecuritySettings.UserPassword = "userPassword";
pdf.SecuritySettings.OwnerPassword = "ownerPassword";
pdf.SecuritySettings.AllowUserPrinting = PdfPrintSecurity.FullPrintRights;
pdf.SecuritySettings.AllowUserCopyPasteContent = false;

pdf.SaveAs("protected.pdf");

using IronPdf;

var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf("<h1>Confidential Document</h1>");

// Set security
pdf.SecuritySettings.UserPassword = "userPassword";
pdf.SecuritySettings.OwnerPassword = "ownerPassword";
pdf.SecuritySettings.AllowUserPrinting = PdfPrintSecurity.FullPrintRights;
pdf.SecuritySettings.AllowUserCopyPasteContent = false;

pdf.SaveAs("protected.pdf");

Imports IronPdf

Dim renderer As New ChromePdfRenderer()
Dim pdf = renderer.RenderHtmlAsPdf("<h1>Confidential Document</h1>")

' Set security
pdf.SecuritySettings.UserPassword = "userPassword"
pdf.SecuritySettings.OwnerPassword = "ownerPassword"
pdf.SecuritySettings.AllowUserPrinting = PdfPrintSecurity.FullPrintRights
pdf.SecuritySettings.AllowUserCopyPasteContent = False

pdf.SaveAs("protected.pdf")

Imports IronPdf

Dim renderer As New ChromePdfRenderer()
Dim pdf = renderer.RenderHtmlAsPdf("<h1>Confidential Document</h1>")

' Set security
pdf.SecuritySettings.UserPassword = "userPassword"
pdf.SecuritySettings.OwnerPassword = "ownerPassword"
pdf.SecuritySettings.AllowUserPrinting = PdfPrintSecurity.FullPrintRights
pdf.SecuritySettings.AllowUserCopyPasteContent = False

pdf.SaveAs("protected.pdf")

有关全面的安全选项，请参阅加密文档。

关键迁移说明

删除所有 Release() 调用

影响最大的改动是删除了手动内存管理。 ComPDFKit需要对文档、页面和文本页面进行显式 Release() 调用。IronPDF通过 .NET 垃圾收集自动处理：

//ComPDFKit- manual cleanup required
document.Release();
page.Release();
textPage.Release();

//IronPDF- no equivalent needed
// GC handles cleanup automatically

//ComPDFKit- manual cleanup required
document.Release();
page.Release();
textPage.Release();

//IronPDF- no equivalent needed
// GC handles cleanup automatically

'ComPDFKit- manual cleanup required
document.Release()
page.Release()
textPage.Release()

'IronPDF- no equivalent needed
' GC handles cleanup automatically

'ComPDFKit- manual cleanup required
document.Release()
page.Release()
textPage.Release()

'IronPDF- no equivalent needed
' GC handles cleanup automatically