C# PDF程式庫

HTML 轉 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

影片

如何使用 iTextSharp | IronPDF 在 C# 中為 PDF 新增數位簽章

Curtis Chau

Updated: 2026年7月19日

從Syncfusion PDF Framework遷移到IronPDF，將您的PDF生成工作流程從一個大型套件中以坐標為基礎的圖形API轉變為以HTML/CSS為優先、使用現代Chromium渲染的獨立程式庫。此指南提供完整的逐步遷移路徑，消除僅限套件的授權、複雜的部署要求以及以坐標為基礎的定位。

為什麼從Syncfusion PDF遷移到IronPDF

了解Syncfusion PDF Framework

Syncfusion PDF Framework是一個全面的程式庫，提供使用C#建立、編輯和保護PDF文件的廣泛功能。它作為Syncfusion's Essential Studio的一部分提供，其中包括多個平台上的上千個組件。

PDF程式庫不能作為單一組件購買。 Syncfusion現提供一個"Document SDK"層級，將PDF、Word、Excel和PowerPoint程式庫與完整的Essential Studio套件一起捆綁，沒有UI組件。需要僅PDF功能的團隊至少必須選擇Document SDK，當其他文件程式庫未使用時，這可能會顯得繁瑣。

捆綁授權問題

Syncfusion的授權模式對僅需要PDF功能的團隊造成顯著挑戰：

**無法按程式庫購買：**PDF被捆綁至Document SDK（PDF + Word + Excel + PowerPoint）或完整的Essential Studio中 — 無法單獨授權
**社區授權限制：**免費層級要求年收入小於100萬美元，開發者不超過5人，且總員工不超過10人，外部資本終生限制為300萬美元
**複雜的部署授權：**網頁、桌面、伺服器部署需不同授權
**需要年度續約：**訂閱模式，需支付年度費用（最短1年期）
**按開發者定價：**費用隨團隊規模線性增長
捆綁冗餘： Document SDK即使您只需要PDF，也會引入Word/Excel/PowerPoint的依賴；完整的Essential Studio更增加1000+ UI組件

Syncfusion PDF與IronPDF比較

|方面| Syncfusion PDF |IronPDF| |--------|----------------|---------| | 購買模式 | Document SDK捆綁或完整的Essential Studio（沒有按程式庫SKU）| 獨立 | |授權| 複雜的層級 | 簡單的按開發者 | | 社區限制 | <$1M revenue, ≤5 devs, ≤10 employees, ≤$3M outside capital | 免費試用，之後授權 | |部署| 多種授權型別 | 一個授權涵蓋所有 | | API風格| 以坐標為基礎的圖形 + HTML轉換器 | HTML/CSS優先 | | HTML引擎 | Blink（單獨的Windows/Linux/Mac NuGets） | 捆綁Chromium | | CSS 支援 | 現代（Blink）— 接近Chromium平價 | 完整CSS3/flexbox/grid | | 依賴關係 |多個套件| 單一NuGet | | 捆綁要求 | 是（Document SDK或Essential Studio） | 否 | | 專注於PDF | 廣泛；是更大捆綁的一部分 | 狹窄；專注於PDF |

IronPDF通過將PDF功能作為獨立產品提供更專注的方法。這一差異顯著影響成本考量和整合的便利性。

對於採用現代.NET的團隊，IronPDF的獨立授權和HTML/CSS優先的方法提供了沒有捆綁依賴的靈活性。

開始之前

前提條件

.NET環境：.NET Framework 4.6.2+ 或.NET Core 3.1+ / .NET 5/6/7/8/9+
NuGet存取： 有能力安裝NuGet套件
IronPDF授權： 從ironpdf.com獲取您的授權金鑰

NuGet包變更

# Remove Syncfusion packages
dotnet remove package Syncfusion.Pdf.Net.Core
dotnet remove package Syncfusion.HtmlToPdfConverter.Net.Windows
dotnet remove package Syncfusion.Licensing

# Install IronPDF
dotnet add package IronPdf

# Remove Syncfusion packages
dotnet remove package Syncfusion.Pdf.Net.Core
dotnet remove package Syncfusion.HtmlToPdfConverter.Net.Windows
dotnet remove package Syncfusion.Licensing

# Install IronPDF
dotnet add package IronPdf

SHELL

授權配置

Syncfusion：

// Must register before any Syncfusion calls
Syncfusion.Licensing.SyncfusionLicenseProvider.RegisterLicense("YOUR-SYNCFUSION-KEY");

// Must register before any Syncfusion calls
Syncfusion.Licensing.SyncfusionLicenseProvider.RegisterLicense("YOUR-SYNCFUSION-KEY");

' Must register before any Syncfusion calls
Syncfusion.Licensing.SyncfusionLicenseProvider.RegisterLicense("YOUR-SYNCFUSION-KEY")

' Must register before any Syncfusion calls
Syncfusion.Licensing.SyncfusionLicenseProvider.RegisterLicense("YOUR-SYNCFUSION-KEY")

IronPDF：

// One-time at startup
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

// One-time at startup
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

' One-time at startup
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY"

' One-time at startup
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY"

完整API參考

名稱空間變更

// Before: Syncfusion PDF
using Syncfusion.Pdf;
using Syncfusion.Pdf.Graphics;
using Syncfusion.Pdf.Parsing;
using Syncfusion.HtmlConverter;
using Syncfusion.Drawing;

// After: IronPDF
using IronPdf;
using IronPdf.Rendering;

// Before: Syncfusion PDF
using Syncfusion.Pdf;
using Syncfusion.Pdf.Graphics;
using Syncfusion.Pdf.Parsing;
using Syncfusion.HtmlConverter;
using Syncfusion.Drawing;

// After: IronPDF
using IronPdf;
using IronPdf.Rendering;

Imports IronPdf
Imports IronPdf.Rendering

Imports IronPdf
Imports IronPdf.Rendering

核心API對應

| Syncfusion |IronPDF| |------------|---------| | PdfDocument | ChromePdfRenderer | | PdfLoadedDocument | PdfDocument.FromFile() | | HtmlToPdfConverter | ChromePdfRenderer | | graphics.DrawString() | HTML文字元素 | | graphics.DrawImage() | <img> 標籤 | | PdfGrid | HTML <table> | | PdfStandardFont | CSS font-family | | PdfBrushes.Black | CSS color: black | | document.Security | pdf.SecuritySettings | | PdfTextExtractor | pdf.ExtractAllText() | | ImportPageRange() | PdfDocument.Merge() | | document.Save(stream) | pdf.SaveAs(path) | | document.Close(true) |不需要|

程式碼遷移範例

範例1：HTML/URL到PDF轉換

之前（Syncfusion PDF）：

// NuGet: Install-Package Syncfusion.Pdf.Net.Core
using Syncfusion.HtmlConverter;
using Syncfusion.Pdf;
using System.IO;

class Program
{
    static void Main()
    {
        // Initialize HTML to PDF converter
        HtmlToPdfConverter htmlConverter = new HtmlToPdfConverter();
        
        // Convert URL to PDF
        PdfDocument document = htmlConverter.Convert("https://www.example.com");
        
        // Save the document
        FileStream fileStream = new FileStream("Output.pdf", FileMode.Create);
        document.Save(fileStream);
        document.Close(true);
        fileStream.Close();
    }
}

// NuGet: Install-Package Syncfusion.Pdf.Net.Core
using Syncfusion.HtmlConverter;
using Syncfusion.Pdf;
using System.IO;

class Program
{
    static void Main()
    {
        // Initialize HTML to PDF converter
        HtmlToPdfConverter htmlConverter = new HtmlToPdfConverter();
        
        // Convert URL to PDF
        PdfDocument document = htmlConverter.Convert("https://www.example.com");
        
        // Save the document
        FileStream fileStream = new FileStream("Output.pdf", FileMode.Create);
        document.Save(fileStream);
        document.Close(true);
        fileStream.Close();
    }
}

' NuGet: Install-Package Syncfusion.Pdf.Net.Core
Imports Syncfusion.HtmlConverter
Imports Syncfusion.Pdf
Imports System.IO

Module Program
    Sub Main()
        ' Initialize HTML to PDF converter
        Dim htmlConverter As New HtmlToPdfConverter()
        
        ' Convert URL to PDF
        Dim document As PdfDocument = htmlConverter.Convert("https://www.example.com")
        
        ' Save the document
        Dim fileStream As New FileStream("Output.pdf", FileMode.Create)
        document.Save(fileStream)
        document.Close(True)
        fileStream.Close()
    End Sub
End Module

' NuGet: Install-Package Syncfusion.Pdf.Net.Core
Imports Syncfusion.HtmlConverter
Imports Syncfusion.Pdf
Imports System.IO

Module Program
    Sub Main()
        ' Initialize HTML to PDF converter
        Dim htmlConverter As New HtmlToPdfConverter()
        
        ' Convert URL to PDF
        Dim document As PdfDocument = htmlConverter.Convert("https://www.example.com")
        
        ' Save the document
        Dim fileStream As New FileStream("Output.pdf", FileMode.Create)
        document.Save(fileStream)
        document.Close(True)
        fileStream.Close()
    End Sub
End Module

之後（IronPDF）：

// NuGet: Install-Package IronPdf
using IronPdf;

class Program
{
    static void Main()
    {
        // Create a PDF from a URL
        var renderer = new ChromePdfRenderer();
        var pdf = renderer.RenderUrlAsPdf("https://www.example.com");
        
        // Save the PDF
        pdf.SaveAs("Output.pdf");
    }
}

// NuGet: Install-Package IronPdf
using IronPdf;

class Program
{
    static void Main()
    {
        // Create a PDF from a URL
        var renderer = new ChromePdfRenderer();
        var pdf = renderer.RenderUrlAsPdf("https://www.example.com");
        
        // Save the PDF
        pdf.SaveAs("Output.pdf");
    }
}

' NuGet: Install-Package IronPdf
Imports IronPdf

Module Program
    Sub Main()
        ' Create a PDF from a URL
        Dim renderer As New ChromePdfRenderer()
        Dim pdf = renderer.RenderUrlAsPdf("https://www.example.com")
        
        ' Save the PDF
        pdf.SaveAs("Output.pdf")
    End Sub
End Module

' NuGet: Install-Package IronPdf
Imports IronPdf

Module Program
    Sub Main()
        ' Create a PDF from a URL
        Dim renderer As New ChromePdfRenderer()
        Dim pdf = renderer.RenderUrlAsPdf("https://www.example.com")
        
        ' Save the PDF
        pdf.SaveAs("Output.pdf")
    End Sub
End Module

此範例展示了基本API差異。 Syncfusion PDF需要一個FileStream，保存並關閉文件和流。

IronPDF使用RenderUrlAsPdf(), 僅需三行程式碼。無需Close()調用—IronPDF自動處理清理。查看更多HTML到PDF文件以獲得完整的範例。

範例2：從文字建立PDF

之前（Syncfusion PDF）：

// NuGet: Install-Package Syncfusion.Pdf.Net.Core
using Syncfusion.Pdf;
using Syncfusion.Pdf.Graphics;
using Syncfusion.Drawing;
using System.IO;

class Program
{
    static void Main()
    {
        // Create a new PDF document
        PdfDocument document = new PdfDocument();
        
        // Add a page
        PdfPage page = document.Pages.Add();
        
        // Create a font
        PdfFont font = new PdfStandardFont(PdfFontFamily.Helvetica, 12);
        
        // Draw text
        page.Graphics.DrawString("Hello, World!", font, PdfBrushes.Black, new PointF(10, 10));
        
        // Save the document
        FileStream fileStream = new FileStream("Output.pdf", FileMode.Create);
        document.Save(fileStream);
        document.Close(true);
        fileStream.Close();
    }
}

// NuGet: Install-Package Syncfusion.Pdf.Net.Core
using Syncfusion.Pdf;
using Syncfusion.Pdf.Graphics;
using Syncfusion.Drawing;
using System.IO;

class Program
{
    static void Main()
    {
        // Create a new PDF document
        PdfDocument document = new PdfDocument();
        
        // Add a page
        PdfPage page = document.Pages.Add();
        
        // Create a font
        PdfFont font = new PdfStandardFont(PdfFontFamily.Helvetica, 12);
        
        // Draw text
        page.Graphics.DrawString("Hello, World!", font, PdfBrushes.Black, new PointF(10, 10));
        
        // Save the document
        FileStream fileStream = new FileStream("Output.pdf", FileMode.Create);
        document.Save(fileStream);
        document.Close(true);
        fileStream.Close();
    }
}

' NuGet: Install-Package Syncfusion.Pdf.Net.Core
Imports Syncfusion.Pdf
Imports Syncfusion.Pdf.Graphics
Imports Syncfusion.Drawing
Imports System.IO

Module Program
    Sub Main()
        ' Create a new PDF document
        Dim document As New PdfDocument()
        
        ' Add a page
        Dim page As PdfPage = document.Pages.Add()
        
        ' Create a font
        Dim font As PdfFont = New PdfStandardFont(PdfFontFamily.Helvetica, 12)
        
        ' Draw text
        page.Graphics.DrawString("Hello, World!", font, PdfBrushes.Black, New PointF(10, 10))
        
        ' Save the document
        Dim fileStream As New FileStream("Output.pdf", FileMode.Create)
        document.Save(fileStream)
        document.Close(True)
        fileStream.Close()
    End Sub
End Module

' NuGet: Install-Package Syncfusion.Pdf.Net.Core
Imports Syncfusion.Pdf
Imports Syncfusion.Pdf.Graphics
Imports Syncfusion.Drawing
Imports System.IO

Module Program
    Sub Main()
        ' Create a new PDF document
        Dim document As New PdfDocument()
        
        ' Add a page
        Dim page As PdfPage = document.Pages.Add()
        
        ' Create a font
        Dim font As PdfFont = New PdfStandardFont(PdfFontFamily.Helvetica, 12)
        
        ' Draw text
        page.Graphics.DrawString("Hello, World!", font, PdfBrushes.Black, New PointF(10, 10))
        
        ' Save the document
        Dim fileStream As New FileStream("Output.pdf", FileMode.Create)
        document.Save(fileStream)
        document.Close(True)
        fileStream.Close()
    End Sub
End Module

之後（IronPDF）：

// NuGet: Install-Package IronPdf
using IronPdf;
using IronPdf.Rendering;

class Program
{
    static void Main()
    {
        // Create a PDF from HTML string
        var renderer = new ChromePdfRenderer();
        var pdf = renderer.RenderHtmlAsPdf("<h1>Hello, World!</h1>");
        
        // Save the document
        pdf.SaveAs("Output.pdf");
    }
}

// NuGet: Install-Package IronPdf
using IronPdf;
using IronPdf.Rendering;

class Program
{
    static void Main()
    {
        // Create a PDF from HTML string
        var renderer = new ChromePdfRenderer();
        var pdf = renderer.RenderHtmlAsPdf("<h1>Hello, World!</h1>");
        
        // Save the document
        pdf.SaveAs("Output.pdf");
    }
}

' NuGet: Install-Package IronPdf
Imports IronPdf
Imports IronPdf.Rendering

Module Program
    Sub Main()
        ' Create a PDF from HTML string
        Dim renderer As New ChromePdfRenderer()
        Dim pdf = renderer.RenderHtmlAsPdf("<h1>Hello, World!</h1>")
        
        ' Save the document
        pdf.SaveAs("Output.pdf")
    End Sub
End Module

' NuGet: Install-Package IronPdf
Imports IronPdf
Imports IronPdf.Rendering

Module Program
    Sub Main()
        ' Create a PDF from HTML string
        Dim renderer As New ChromePdfRenderer()
        Dim pdf = renderer.RenderHtmlAsPdf("<h1>Hello, World!</h1>")
        
        ' Save the document
        pdf.SaveAs("Output.pdf")
    End Sub
End Module

Syncfusion PDF使用坐標為基礎的圖形模型。您建立一個page.Graphics.DrawString()。最後，您管理FileStream建立和處理。

IronPDF使用HTML/CSS優先的方法。 Instead of coordinates, you write <h1>Hello, World!</h1> and let CSS handle positioning, fonts, and colors. 這種方法更簡單、易於維護，並利用開發者已有的技能。在我們的教程中了解更多。

範例3：合併PDF文件

之前（Syncfusion PDF）：

// NuGet: Install-Package Syncfusion.Pdf.Net.Core
using Syncfusion.Pdf;
using Syncfusion.Pdf.Parsing;
using System.IO;

class Program
{
    static void Main()
    {
        // Load the first PDF document
        FileStream stream1 = new FileStream("Document1.pdf", FileMode.Open, FileAccess.Read);
        PdfLoadedDocument loadedDocument1 = new PdfLoadedDocument(stream1);
        
        // Load the second PDF document
        FileStream stream2 = new FileStream("Document2.pdf", FileMode.Open, FileAccess.Read);
        PdfLoadedDocument loadedDocument2 = new PdfLoadedDocument(stream2);
        
        // Merge the documents
        PdfDocument finalDocument = new PdfDocument();
        finalDocument.ImportPageRange(loadedDocument1, 0, loadedDocument1.Pages.Count - 1);
        finalDocument.ImportPageRange(loadedDocument2, 0, loadedDocument2.Pages.Count - 1);
        
        // Save the merged document
        FileStream outputStream = new FileStream("Merged.pdf", FileMode.Create);
        finalDocument.Save(outputStream);
        
        // Close all documents
        finalDocument.Close(true);
        loadedDocument1.Close(true);
        loadedDocument2.Close(true);
        stream1.Close();
        stream2.Close();
        outputStream.Close();
    }
}

// NuGet: Install-Package Syncfusion.Pdf.Net.Core
using Syncfusion.Pdf;
using Syncfusion.Pdf.Parsing;
using System.IO;

class Program
{
    static void Main()
    {
        // Load the first PDF document
        FileStream stream1 = new FileStream("Document1.pdf", FileMode.Open, FileAccess.Read);
        PdfLoadedDocument loadedDocument1 = new PdfLoadedDocument(stream1);
        
        // Load the second PDF document
        FileStream stream2 = new FileStream("Document2.pdf", FileMode.Open, FileAccess.Read);
        PdfLoadedDocument loadedDocument2 = new PdfLoadedDocument(stream2);
        
        // Merge the documents
        PdfDocument finalDocument = new PdfDocument();
        finalDocument.ImportPageRange(loadedDocument1, 0, loadedDocument1.Pages.Count - 1);
        finalDocument.ImportPageRange(loadedDocument2, 0, loadedDocument2.Pages.Count - 1);
        
        // Save the merged document
        FileStream outputStream = new FileStream("Merged.pdf", FileMode.Create);
        finalDocument.Save(outputStream);
        
        // Close all documents
        finalDocument.Close(true);
        loadedDocument1.Close(true);
        loadedDocument2.Close(true);
        stream1.Close();
        stream2.Close();
        outputStream.Close();
    }
}

' NuGet: Install-Package Syncfusion.Pdf.Net.Core
Imports Syncfusion.Pdf
Imports Syncfusion.Pdf.Parsing
Imports System.IO

Module Program
    Sub Main()
        ' Load the first PDF document
        Dim stream1 As FileStream = New FileStream("Document1.pdf", FileMode.Open, FileAccess.Read)
        Dim loadedDocument1 As PdfLoadedDocument = New PdfLoadedDocument(stream1)
        
        ' Load the second PDF document
        Dim stream2 As FileStream = New FileStream("Document2.pdf", FileMode.Open, FileAccess.Read)
        Dim loadedDocument2 As PdfLoadedDocument = New PdfLoadedDocument(stream2)
        
        ' Merge the documents
        Dim finalDocument As PdfDocument = New PdfDocument()
        finalDocument.ImportPageRange(loadedDocument1, 0, loadedDocument1.Pages.Count - 1)
        finalDocument.ImportPageRange(loadedDocument2, 0, loadedDocument2.Pages.Count - 1)
        
        ' Save the merged document
        Dim outputStream As FileStream = New FileStream("Merged.pdf", FileMode.Create)
        finalDocument.Save(outputStream)
        
        ' Close all documents
        finalDocument.Close(True)
        loadedDocument1.Close(True)
        loadedDocument2.Close(True)
        stream1.Close()
        stream2.Close()
        outputStream.Close()
    End Sub
End Module

' NuGet: Install-Package Syncfusion.Pdf.Net.Core
Imports Syncfusion.Pdf
Imports Syncfusion.Pdf.Parsing
Imports System.IO

Module Program
    Sub Main()
        ' Load the first PDF document
        Dim stream1 As FileStream = New FileStream("Document1.pdf", FileMode.Open, FileAccess.Read)
        Dim loadedDocument1 As PdfLoadedDocument = New PdfLoadedDocument(stream1)
        
        ' Load the second PDF document
        Dim stream2 As FileStream = New FileStream("Document2.pdf", FileMode.Open, FileAccess.Read)
        Dim loadedDocument2 As PdfLoadedDocument = New PdfLoadedDocument(stream2)
        
        ' Merge the documents
        Dim finalDocument As PdfDocument = New PdfDocument()
        finalDocument.ImportPageRange(loadedDocument1, 0, loadedDocument1.Pages.Count - 1)
        finalDocument.ImportPageRange(loadedDocument2, 0, loadedDocument2.Pages.Count - 1)
        
        ' Save the merged document
        Dim outputStream As FileStream = New FileStream("Merged.pdf", FileMode.Create)
        finalDocument.Save(outputStream)
        
        ' Close all documents
        finalDocument.Close(True)
        loadedDocument1.Close(True)
        loadedDocument2.Close(True)
        stream1.Close()
        stream2.Close()
        outputStream.Close()
    End Sub
End Module

之後（IronPDF）：

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

class Program
{
    static void Main()
    {
        // Load PDF documents
        var pdf1 = PdfDocument.FromFile("Document1.pdf");
        var pdf2 = PdfDocument.FromFile("Document2.pdf");
        
        // Merge PDFs
        var merged = PdfDocument.Merge(new List<PdfDocument> { pdf1, pdf2 });
        
        // Save the merged document
        merged.SaveAs("Merged.pdf");
    }
}

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

class Program
{
    static void Main()
    {
        // Load PDF documents
        var pdf1 = PdfDocument.FromFile("Document1.pdf");
        var pdf2 = PdfDocument.FromFile("Document2.pdf");
        
        // Merge PDFs
        var merged = PdfDocument.Merge(new List<PdfDocument> { pdf1, pdf2 });
        
        // Save the merged document
        merged.SaveAs("Merged.pdf");
    }
}

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

Class Program
    Shared Sub Main()
        ' Load PDF documents
        Dim pdf1 = PdfDocument.FromFile("Document1.pdf")
        Dim pdf2 = PdfDocument.FromFile("Document2.pdf")
        
        ' Merge PDFs
        Dim merged = PdfDocument.Merge(New List(Of PdfDocument) From {pdf1, pdf2})
        
        ' Save the merged document
        merged.SaveAs("Merged.pdf")
    End Sub
End Class

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

Class Program
    Shared Sub Main()
        ' Load PDF documents
        Dim pdf1 = PdfDocument.FromFile("Document1.pdf")
        Dim pdf2 = PdfDocument.FromFile("Document2.pdf")
        
        ' Merge PDFs
        Dim merged = PdfDocument.Merge(New List(Of PdfDocument) From {pdf1, pdf2})
        
        ' Save the merged document
        merged.SaveAs("Merged.pdf")
    End Sub
End Class

合併PDF的對比是顯著的。 Syncfusion PDF需要為每個輸入文件建立FileStream，然後關閉六個獨立物件 (finalDocument, loadedDocument1, loadedDocument2, stream1, stream2, outputStream)。

IronPDF使用PdfDocument.Merge()方法接受文件列表。無需流管理，無需手動頁面範圍計算，無需關閉調用。

API哲學的關鍵差異

坐標為基礎與HTML/CSS優先

Syncfusion PDF使用傳統PDF程式庫延續來的坐標為基礎的圖形模型：

// Syncfusion: 手動 positioning
page.Graphics.DrawString("Text", font, PdfBrushes.Black, new PointF(100, 200));
page.Graphics.DrawRectangle(brush, new RectangleF(50, 50, 200, 100));

// Syncfusion: 手動 positioning
page.Graphics.DrawString("Text", font, PdfBrushes.Black, new PointF(100, 200));
page.Graphics.DrawRectangle(brush, new RectangleF(50, 50, 200, 100));

IronPDF使用HTML/CSS進行佈局：

// IronPDF: CSS-based positioning
var html = @"
<div style='margin: 50px; padding: 20px; border: 1px solid black;'>
    <p style='color: black;'>Text</p>
</div>";
var pdf = renderer.RenderHtmlAsPdf(html);

// IronPDF: CSS-based positioning
var html = @"
<div style='margin: 50px; padding: 20px; border: 1px solid black;'>
    <p style='color: black;'>Text</p>
</div>";
var pdf = renderer.RenderHtmlAsPdf(html);

' IronPDF: CSS-based positioning
Dim html As String = "
<div style='margin: 50px; padding: 20px; border: 1px solid black;'>
    <p style='color: black;'>Text</p>
</div>"
Dim pdf = renderer.RenderHtmlAsPdf(html)

' IronPDF: CSS-based positioning
Dim html As String = "
<div style='margin: 50px; padding: 20px; border: 1px solid black;'>
    <p style='color: black;'>Text</p>
</div>"
Dim pdf = renderer.RenderHtmlAsPdf(html)

HTML/CSS方法對網頁開發者更直觀、更易於維護，並在不同頁面尺寸下產生一致的結果。

流管理與自動清理

Syncfusion PDF需要明確流和文件處理：

// Syncfusion: 手動 cleanup
FileStream fileStream = new FileStream("Output.pdf", FileMode.Create);
document.Save(fileStream);
document.Close(true);
fileStream.Close();

// Syncfusion: 手動 cleanup
FileStream fileStream = new FileStream("Output.pdf", FileMode.Create);
document.Save(fileStream);
document.Close(true);
fileStream.Close();

IronPDF自動處理清理：

// IronPDF:自動cleanup
pdf.SaveAs("Output.pdf");

// IronPDF:自動cleanup
pdf.SaveAs("Output.pdf");

功能比較

| 功能 | Syncfusion PDF |IronPDF| |---------|----------------|---------| | 獨立購買 | 否（Document SDK或Essential Studio）| 是 | |授權| 商業授權附社區限制 | 簡化的商業 | | HTML引擎 | Blink（平台專用NuGets） | 捆綁Chromium | | CSS3支援 | 通過Blink現代 | 完整（flexbox, grid） | | API風格| 以坐標為基礎的圖形 + HTML轉換器 | HTML/CSS優先 | | 流管理 | 手動 |自動| | 依賴關係 |多個套件| 單一NuGet | |部署複雜性| 潛在複雜 | 簡單明了 |

遷移檢查表

遷移前

編目所有程式碼庫中的Syncfusion PDF使用
記錄授權成本和部署要求
確認PdfGrid, PdfGraphics, 和HtmlToPdfConverter的使用
獲取IronPDF授權金鑰來自ironpdf.com

程式碼更新

移除Syncfusion套件 (Syncfusion.Pdf.Net.Core, Syncfusion.HtmlToPdfConverter.Net.Windows, Syncfusion.Licensing)
安裝IronPdf NuGet套件
更新命名空間導入 (using Syncfusion.Pdf; → using IronPdf;)
替換IronPdf.License.LicenseKey = "..."
替換RenderHtmlAsPdf()
替換PdfDocument + Pages.Add() + ChromePdfRenderer.RenderHtmlAsPdf()
替換PdfDocument.FromFile()
替換PdfDocument.Merge()
替換pdf.SaveAs(path)
移除所有stream.Close()調用
替換PdfGrid為HTML <table>元素
替換PdfStandardFont為CSS font-family
替換PdfBrushes為CSS color屬性

測試

PDF輸出的視覺比較
驗證CSS渲染改進（flexbox、grid現在可用）
測試文字提取
測試合併和分割
性能比較

Please note: Syncfusion為其各自擁有者的註冊商標。本站與Syncfusion無關，不受其認可或贊助。所有產品名稱、標誌和品牌均為其各自所有者的財產。比較僅供參考，反映撰寫時公開可用的資訊。

Curtis Chau

Chat with engineering team now

Technical Writer

Curtis Chau holds a Bachelor’s degree in Computer Science (Carleton University) and specializes in front-end development with expertise in Node.js, TypeScript, JavaScript, and React. Passionate about crafting intuitive and aesthetically pleasing user interfaces, Curtis enjoys working with modern frameworks and creating well-structured, visually appealing manuals.

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