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#设置和编辑PDF元数据

Curtis Chau

Updated: 2026年7月19日

从GdPicture.NET SDK迁移到IronPDF可为 .NET 开发人员提供一种专注、精简的 PDF 生成方法。本指南提供了一个全面、循序渐进的迁移路径，用专为当代 .NET 开发设计的现代 PDF 专用 API 取代了复杂的文档成像 SDK 模式。

为什么要从GdPicture.NET SDK迁移到 IronPDF．

###GdPicture.NET SDK面临的挑战

GdPicture.NET SDK（现已更名为 Nutrient）是一个全面的文档成像 SDK，在 PDF 开发中面临着一些挑战：

1.**对于仅处理 PDF 的项目来说有点过头了：**GdPicture.NET SDK是一个完整的文档图像处理套件，包括 OCR、条形码识别、扫描和图像处理。如果您只需要 PDF 功能，那么您就需要为您永远用不上的功能付费。

2.**复杂的许可：**多个产品级别（GdPicture.NET 14、GdPicture.API、Ultimate、Professional），SKU 组合令人困惑，并且有年度订阅要求。

3.**企业定价：**仅 PDF 插件的许可费用起价为 2,999 美元，而终极版的价格则高达 10,000 美元以上。按开发人员发放 License 会给不断壮大的团队增加大量开销。

4.**学习曲线陡峭：**该 API 是围绕文档图像概念设计的，而不是现代 .NET 模式。类似于GdPictureStatus枚举检查以及1为基的页数相比当代C#惯例显得过时。

**状态码模式：**每个操作返回一个GdPictureStatus枚举，必须检查—错误时不抛出异常，使得错误处理冗长且重复。
**手动资源管理：**需要显式调用Release()。 SDK 并不完全遵循标准的 .NET 处置模式。
**版本锁定：**命名空间GdPicture14包括版本号，使得主要版本升级需要在整个代码库中更改命名空间。

8.**品牌重塑带来的混乱：**最近更名为"Nutrient"导致 gdpicture.com 和 nutrient.io 之间的文档出现碎片化，使支持和学习变得复杂。

###GdPicture.NET SDK与IronPDFfor .NET 对比

方面	GdPicture.NET SDK	IronPDF
翻译重点	文档成像套件（PDF 过犹不及）	PDF 专用库
定价	2,999 美元-10,000 美元以上企业级	具有竞争力，与业务相匹配
API 风格	状态代码、人工管理	异常、IDisposable、现代 .NET
学习曲线	Steep（图像 SDK 概念）	简单（熟悉 HTML/CSS）
HTML 渲染	基本的内部引擎	带有 CSS3/JS 的最新 Chromium
页面索引	1-索引	0 索引（标准 .NET Standard）
线程安全	需要手动同步	线程安全设计
名称空间	特定版本 (`GdPicture14`)	稳定版 (`IronPdf`)

IronPDF与现代.NET模式和惯例一致，使其非常适合当前.NET版本的团队使用。

迁移复杂性评估

按功能估算的工作量

特征	迁移复杂性
HTML 至 PDF	low
URL 至 PDF	low
合并 PDF	low
拆分 PDF	low
水印	low
文本提取	low
密码保护	语言
表格字段	语言
数字签名	中高级
OCR	高的
条形码识别	不适用

迁移决策矩阵

您的情况	建议
纯 PDF 操作	迁移--显著简化并节约成本
大量使用 OCR	考虑将 IronOCR 作为配套产品
条形码/扫描需求	这些功能请保留 GdPicture.NET SDK，PDF 请使用 IronPDF
完整的文档成像	评估您是否实际使用了所有功能

开始之前

前提条件

**.NET版本：**IronPDF支持.NET Framework 4.6.2+和.NET Core 2.0+ / .NET 5+ 2.**许可证密钥：**从ironpdf.com获取您的IronPDF许可证密钥。 3.**备份：**创建一个用于迁移工作的分支

明确GdPicture.NET SDK的所有用法

# Find allGdPicture.NET SDKreferences in your codebase
grep -r "GdPicture14\|GdPicturePDF\|GdPictureDocumentConverter\|GdPictureStatus\|LicenseManager\.RegisterKEY" --include="*.cs" .

# Find all GdPicture package references
grep -r "GdPicture" --include="*.csproj" .

# Find allGdPicture.NET SDKreferences in your codebase
grep -r "GdPicture14\|GdPicturePDF\|GdPictureDocumentConverter\|GdPictureStatus\|LicenseManager\.RegisterKEY" --include="*.cs" .

# Find all GdPicture package references
grep -r "GdPicture" --include="*.csproj" .

SHELL

NuGet 软件包变更

# RemoveGdPicture.NET SDKpackages
dotnet remove package GdPicture.NET.14
dotnet remove package GdPicture.NET.14.API
dotnet remove package GdPicture
dotnet remove package GdPicture.API

# Install IronPDF
dotnet add package IronPdf

# RemoveGdPicture.NET SDKpackages
dotnet remove package GdPicture.NET.14
dotnet remove package GdPicture.NET.14.API
dotnet remove package GdPicture
dotnet remove package GdPicture.API

# Install IronPDF
dotnet add package IronPdf

SHELL

快速启动迁移

步骤 1：更新许可配置

之前（GdPicture.NET SDK）：

// Must be called before anyGdPicture.NET SDKoperations
LicenseManager.RegisterKEY("YOUR-GDPICTURE-LICENSE-KEY");

// Must be called before anyGdPicture.NET SDKoperations
LicenseManager.RegisterKEY("YOUR-GDPICTURE-LICENSE-KEY");

' Must be called before any GdPicture.NET SDK operations
LicenseManager.RegisterKEY("YOUR-GDPICTURE-LICENSE-KEY")

' Must be called before any GdPicture.NET SDK operations
LicenseManager.RegisterKEY("YOUR-GDPICTURE-LICENSE-KEY")

After (IronPDF)：

// Set once at application startup
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

// Or in appsettings.json:
// { "IronPdf.License.LicenseKey": "YOUR-LICENSE-KEY" }

// Set once at application startup
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

// Or in appsettings.json:
// { "IronPdf.License.LicenseKey": "YOUR-LICENSE-KEY" }

Imports IronPdf

' Set once at application startup
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY"

' Or in appsettings.json:
' { "IronPdf.License.LicenseKey": "YOUR-LICENSE-KEY" }

Imports IronPdf

' Set once at application startup
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY"

' Or in appsettings.json:
' { "IronPdf.License.LicenseKey": "YOUR-LICENSE-KEY" }

步骤 2：更新名称空间导入

// Before (GdPicture.NET SDK)
using GdPicture14;

// After (IronPDF)
using IronPdf;
using IronPdf.Editing;

// Before (GdPicture.NET SDK)
using GdPicture14;

// After (IronPDF)
using IronPdf;
using IronPdf.Editing;

Imports IronPdf
Imports IronPdf.Editing

Imports IronPdf
Imports IronPdf.Editing

步骤 3：基本转换模式

GdPicture.NET SDK 移植中最重要的变化是取消了冗长的状态检查模式：

之前（GdPicture.NET SDK）：

using GdPicture14;

LicenseManager.RegisterKEY("YOUR-GDPICTURE-LICENSE-KEY");

using (GdPictureDocumentConverter converter = new GdPictureDocumentConverter())
{
    GdPictureStatus status = converter.LoadFromHTMLString("<h1>Hello World</h1>");

    if (status == GdPictureStatus.OK)
    {
        status = converter.SaveAsPDF("output.pdf");

        if (status != GdPictureStatus.OK)
        {
            Console.WriteLine($"Error: {status}");
        }
    }
    else
    {
        Console.WriteLine($"Load error: {status}");
    }
}

using GdPicture14;

LicenseManager.RegisterKEY("YOUR-GDPICTURE-LICENSE-KEY");

using (GdPictureDocumentConverter converter = new GdPictureDocumentConverter())
{
    GdPictureStatus status = converter.LoadFromHTMLString("<h1>Hello World</h1>");

    if (status == GdPictureStatus.OK)
    {
        status = converter.SaveAsPDF("output.pdf");

        if (status != GdPictureStatus.OK)
        {
            Console.WriteLine($"Error: {status}");
        }
    }
    else
    {
        Console.WriteLine($"Load error: {status}");
    }
}

Imports GdPicture14

LicenseManager.RegisterKEY("YOUR-GDPICTURE-LICENSE-KEY")

Using converter As New GdPictureDocumentConverter()
    Dim status As GdPictureStatus = converter.LoadFromHTMLString("<h1>Hello World</h1>")

    If status = GdPictureStatus.OK Then
        status = converter.SaveAsPDF("output.pdf")

        If status <> GdPictureStatus.OK Then
            Console.WriteLine($"Error: {status}")
        End If
    Else
        Console.WriteLine($"Load error: {status}")
    End If
End Using

Imports GdPicture14

LicenseManager.RegisterKEY("YOUR-GDPICTURE-LICENSE-KEY")

Using converter As New GdPictureDocumentConverter()
    Dim status As GdPictureStatus = converter.LoadFromHTMLString("<h1>Hello World</h1>")

    If status = GdPictureStatus.OK Then
        status = converter.SaveAsPDF("output.pdf")

        If status <> GdPictureStatus.OK Then
            Console.WriteLine($"Error: {status}")
        End If
    Else
        Console.WriteLine($"Load error: {status}")
    End If
End Using

After (IronPDF)：

using IronPdf;

IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1>");
pdf.SaveAs("output.pdf");

using IronPdf;

IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1>");
pdf.SaveAs("output.pdf");

Imports IronPdf

IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY"

Dim renderer As New ChromePdfRenderer()
Dim pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1>")
pdf.SaveAs("output.pdf")

Imports IronPdf

IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY"

Dim renderer As New ChromePdfRenderer()
Dim pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1>")
pdf.SaveAs("output.pdf")

关键差异：

无状态检查-错误时出现例外情况
无需对呈现器进行明确处理
现代流畅的 API
基于 Chromium 的渲染，更好地支持 HTML/CSS

完整的 API 参考

命名空间映射

GdPicture.NET SDK	IronPDF
`GdPicture14`	`IronPdf`
`GdPicture14.PDF`	`IronPdf`
`GdPicture14.Imaging`	不适用（不需要）

核心类映射

GdPicture.NET SDK	IronPDF	说明
`GdPicturePDF`	`PdfDocument`	主要 PDF 文档类别
`GdPictureDocumentConverter`	`ChromePdfRenderer`	HTML/URL 到 PDF 的转换
`LicenseManager`	`IronPdf.License`	许可证管理
`GdPictureStatus`	例外情况	错误处理

文档加载方法

GdPicture.NET SDK	IronPDF
`pdf.LoadFromFile(path, loadInMemory)`	`PdfDocument.FromFile(path)`
`pdf.LoadFromFile(path, password, loadInMemory)`	`PdfDocument.FromFile(path, password)`
`converter.LoadFromHTMLString(html)`	`renderer.RenderHtmlAsPdf(html)`
`converter.LoadFromURL(url)`	`renderer.RenderUrlAsPdf(url)`

页面操作

GdPicture.NET SDK	IronPDF
`pdf.GetPageCount()`	`pdf.PageCount`
`pdf.SelectPage(pageNo)`	`pdf.Pages[index]`
`pdf.GetPageWidth()`	`pdf.Pages[i].Width`
`pdf.GetPageHeight()`	`pdf.Pages[i].Height`

合并和拆分操作

GdPicture.NET SDK	IronPDF
`pdf1.MergePages(pdf2)`	`PdfDocument.Merge(pdf1, pdf2)`
`pdf.ExtractPages(start, end)`	`pdf.CopyPages(indices)`

水印操作

GdPicture.NET SDK	IronPDF
`pdf.DrawText(...)`循环	`pdf.ApplyWatermark(html)`
`pdf.SetTextColor(color)`	CSS 定型
`pdf.SetTextSize(size)`	CSS 定型

代码迁移示例

示例 1：HTML 到 PDF 的转换

之前（GdPicture.NET SDK）：

// NuGet: Install-Package GdPicture.NET
using GdPicture14;
using System;

class Program
{
    static void Main()
    {
        using (GdPictureDocumentConverter converter = new GdPictureDocumentConverter())
        {
            string htmlContent = "<html><body><h1>Hello World</h1></body></html>";
            GdPictureStatus status = converter.LoadFromHTMLString(htmlContent);
            
            if (status == GdPictureStatus.OK)
            {
                converter.SaveAsPDF("output.pdf");
            }
        }
    }
}

// NuGet: Install-Package GdPicture.NET
using GdPicture14;
using System;

class Program
{
    static void Main()
    {
        using (GdPictureDocumentConverter converter = new GdPictureDocumentConverter())
        {
            string htmlContent = "<html><body><h1>Hello World</h1></body></html>";
            GdPictureStatus status = converter.LoadFromHTMLString(htmlContent);
            
            if (status == GdPictureStatus.OK)
            {
                converter.SaveAsPDF("output.pdf");
            }
        }
    }
}

' NuGet: Install-Package GdPicture.NET
Imports GdPicture14
Imports System

Class Program
    Shared Sub Main()
        Using converter As New GdPictureDocumentConverter()
            Dim htmlContent As String = "<html><body><h1>Hello World</h1></body></html>"
            Dim status As GdPictureStatus = converter.LoadFromHTMLString(htmlContent)
            
            If status = GdPictureStatus.OK Then
                converter.SaveAsPDF("output.pdf")
            End If
        End Using
    End Sub
End Class

' NuGet: Install-Package GdPicture.NET
Imports GdPicture14
Imports System

Class Program
    Shared Sub Main()
        Using converter As New GdPictureDocumentConverter()
            Dim htmlContent As String = "<html><body><h1>Hello World</h1></body></html>"
            Dim status As GdPictureStatus = converter.LoadFromHTMLString(htmlContent)
            
            If status = GdPictureStatus.OK Then
                converter.SaveAsPDF("output.pdf")
            End If
        End Using
    End Sub
End Class

After (IronPDF)：

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

class Program
{
    static void Main()
    {
        var renderer = new ChromePdfRenderer();
        string htmlContent = "<html><body><h1>Hello World</h1></body></html>";
        var pdf = renderer.RenderHtmlAsPdf(htmlContent);
        pdf.SaveAs("output.pdf");
    }
}

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

class Program
{
    static void Main()
    {
        var renderer = new ChromePdfRenderer();
        string htmlContent = "<html><body><h1>Hello World</h1></body></html>";
        var pdf = renderer.RenderHtmlAsPdf(htmlContent);
        pdf.SaveAs("output.pdf");
    }
}

Imports IronPdf
Imports System

Class Program
    Shared Sub Main()
        Dim renderer = New ChromePdfRenderer()
        Dim htmlContent As String = "<html><body><h1>Hello World</h1></body></html>"
        Dim pdf = renderer.RenderHtmlAsPdf(htmlContent)
        pdf.SaveAs("output.pdf")
    End Sub
End Class

Imports IronPdf
Imports System

Class Program
    Shared Sub Main()
        Dim renderer = New ChromePdfRenderer()
        Dim htmlContent As String = "<html><body><h1>Hello World</h1></body></html>"
        Dim pdf = renderer.RenderHtmlAsPdf(htmlContent)
        pdf.SaveAs("output.pdf")
    End Sub
End Class

IronPDF的ChromePdfRenderer使用现代Chromium引擎进行准确的HTML/CSS渲染，无需检查状态码。有关更多 HTML 渲染选项，请参阅 HTML to PDF 文档。

示例 2：合并多个 PDF 文件

之前（GdPicture.NET SDK）：

// NuGet: Install-Package GdPicture.NET
using GdPicture14;
using System;

class Program
{
    static void Main()
    {
        using (GdPicturePDF pdf1 = new GdPicturePDF())
        using (GdPicturePDF pdf2 = new GdPicturePDF())
        {
            pdf1.LoadFromFile("document1.pdf", false);
            pdf2.LoadFromFile("document2.pdf", false);
            
            pdf1.MergePages(pdf2);
            pdf1.SaveToFile("merged.pdf");
        }
    }
}

// NuGet: Install-Package GdPicture.NET
using GdPicture14;
using System;

class Program
{
    static void Main()
    {
        using (GdPicturePDF pdf1 = new GdPicturePDF())
        using (GdPicturePDF pdf2 = new GdPicturePDF())
        {
            pdf1.LoadFromFile("document1.pdf", false);
            pdf2.LoadFromFile("document2.pdf", false);
            
            pdf1.MergePages(pdf2);
            pdf1.SaveToFile("merged.pdf");
        }
    }
}

' NuGet: Install-Package GdPicture.NET
Imports GdPicture14
Imports System

Module Program
    Sub Main()
        Using pdf1 As New GdPicturePDF(), pdf2 As New GdPicturePDF()
            pdf1.LoadFromFile("document1.pdf", False)
            pdf2.LoadFromFile("document2.pdf", False)

            pdf1.MergePages(pdf2)
            pdf1.SaveToFile("merged.pdf")
        End Using
    End Sub
End Module

' NuGet: Install-Package GdPicture.NET
Imports GdPicture14
Imports System

Module Program
    Sub Main()
        Using pdf1 As New GdPicturePDF(), pdf2 As New GdPicturePDF()
            pdf1.LoadFromFile("document1.pdf", False)
            pdf2.LoadFromFile("document2.pdf", False)

            pdf1.MergePages(pdf2)
            pdf1.SaveToFile("merged.pdf")
        End Using
    End Sub
End Module

After (IronPDF)：

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

class Program
{
    static void Main()
    {
        var pdf1 = PdfDocument.FromFile("document1.pdf");
        var pdf2 = PdfDocument.FromFile("document2.pdf");
        
        var merged = PdfDocument.Merge(new List<PdfDocument> { pdf1, pdf2 });
        merged.SaveAs("merged.pdf");
    }
}

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

class Program
{
    static void Main()
    {
        var pdf1 = PdfDocument.FromFile("document1.pdf");
        var pdf2 = PdfDocument.FromFile("document2.pdf");
        
        var merged = PdfDocument.Merge(new List<PdfDocument> { pdf1, pdf2 });
        merged.SaveAs("merged.pdf");
    }
}

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

Class Program
    Shared Sub Main()
        Dim pdf1 = PdfDocument.FromFile("document1.pdf")
        Dim pdf2 = PdfDocument.FromFile("document2.pdf")

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

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

Class Program
    Shared Sub Main()
        Dim pdf1 = PdfDocument.FromFile("document1.pdf")
        Dim pdf2 = PdfDocument.FromFile("document2.pdf")

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

IronPDF的静态Merge方法接受文档列表，使得在单次操作中结合多个PDF变得容易。了解有关合并和拆分 PDF 的更多信息。

示例 3：为所有页面添加水印

之前（GdPicture.NET SDK）：

// NuGet: Install-Package GdPicture.NET
using GdPicture14;
using System;
using System.Drawing;

class Program
{
    static void Main()
    {
        using (GdPicturePDF pdf = new GdPicturePDF())
        {
            pdf.LoadFromFile("input.pdf", false);
            
            for (int i = 1; i <= pdf.GetPageCount(); i++)
            {
                pdf.SelectPage(i);
                pdf.SetTextColor(Color.Red);
                pdf.SetTextSize(48);
                pdf.DrawText("CONFIDENTIAL", 200, 400);
            }
            
            pdf.SaveToFile("watermarked.pdf");
        }
    }
}

// NuGet: Install-Package GdPicture.NET
using GdPicture14;
using System;
using System.Drawing;

class Program
{
    static void Main()
    {
        using (GdPicturePDF pdf = new GdPicturePDF())
        {
            pdf.LoadFromFile("input.pdf", false);
            
            for (int i = 1; i <= pdf.GetPageCount(); i++)
            {
                pdf.SelectPage(i);
                pdf.SetTextColor(Color.Red);
                pdf.SetTextSize(48);
                pdf.DrawText("CONFIDENTIAL", 200, 400);
            }
            
            pdf.SaveToFile("watermarked.pdf");
        }
    }
}

' NuGet: Install-Package GdPicture.NET
Imports GdPicture14
Imports System
Imports System.Drawing

Module Program
    Sub Main()
        Using pdf As New GdPicturePDF()
            pdf.LoadFromFile("input.pdf", False)

            For i As Integer = 1 To pdf.GetPageCount()
                pdf.SelectPage(i)
                pdf.SetTextColor(Color.Red)
                pdf.SetTextSize(48)
                pdf.DrawText("CONFIDENTIAL", 200, 400)
            Next

            pdf.SaveToFile("watermarked.pdf")
        End Using
    End Sub
End Module

' NuGet: Install-Package GdPicture.NET
Imports GdPicture14
Imports System
Imports System.Drawing

Module Program
    Sub Main()
        Using pdf As New GdPicturePDF()
            pdf.LoadFromFile("input.pdf", False)

            For i As Integer = 1 To pdf.GetPageCount()
                pdf.SelectPage(i)
                pdf.SetTextColor(Color.Red)
                pdf.SetTextSize(48)
                pdf.DrawText("CONFIDENTIAL", 200, 400)
            Next

            pdf.SaveToFile("watermarked.pdf")
        End Using
    End Sub
End Module

After (IronPDF)：

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

class Program
{
    static void Main()
    {
        var pdf = PdfDocument.FromFile("input.pdf");
        
        pdf.ApplyWatermark("<h1 style='color:red;'>CONFIDENTIAL</h1>", 50, VerticalAlignment.Middle, HorizontalAlignment.Center);
        
        pdf.SaveAs("watermarked.pdf");
    }
}

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

class Program
{
    static void Main()
    {
        var pdf = PdfDocument.FromFile("input.pdf");
        
        pdf.ApplyWatermark("<h1 style='color:red;'>CONFIDENTIAL</h1>", 50, VerticalAlignment.Middle, HorizontalAlignment.Center);
        
        pdf.SaveAs("watermarked.pdf");
    }
}

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

Module Program
    Sub Main()
        Dim pdf = PdfDocument.FromFile("input.pdf")
        
        pdf.ApplyWatermark("<h1 style='color:red;'>CONFIDENTIAL</h1>", 50, VerticalAlignment.Middle, HorizontalAlignment.Center)
        
        pdf.SaveAs("watermarked.pdf")
    End Sub
End Module

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

Module Program
    Sub Main()
        Dim pdf = PdfDocument.FromFile("input.pdf")
        
        pdf.ApplyWatermark("<h1 style='color:red;'>CONFIDENTIAL</h1>", 50, VerticalAlignment.Middle, HorizontalAlignment.Center)
        
        pdf.SaveAs("watermarked.pdf")
    End Sub
End Module

GdPicture.NET SDK 从基于坐标的文本绘制迁移到基于 HTML 的水印，大大简化了代码。 IronPDF的ApplyWatermark方法使用HTML/CSS样式，消除了手动页面迭代和坐标计算的需要。有关其他选项，请参阅完整的 watermarking 文档。

示例 4：密码保护和安全性

之前（GdPicture.NET SDK）：

using GdPicture14;

class Program
{
    static void Main()
    {
        LicenseManager.RegisterKEY("YOUR-GDPICTURE-LICENSE-KEY");

        using (GdPicturePDF pdf = new GdPicturePDF())
        {
            GdPictureStatus status = pdf.LoadFromFile("document.pdf", false);

            if (status != GdPictureStatus.OK) return;

            // Save with encryption - many boolean parameters
            status = pdf.SaveToFile(
                "protected.pdf",
                PdfEncryption.PdfEncryption256BitAES,
                "user123",      // User password
                "owner456",     // Owner password
                true,           // Can print
                false,          // Cannot copy
                false,          // Cannot modify
                false,          // Cannot add notes
                true,           // Can fill forms
                false,          // Cannot extract
                false,          // Cannot assemble
                true            // Can print high quality
            );
        }
    }
}

using GdPicture14;

class Program
{
    static void Main()
    {
        LicenseManager.RegisterKEY("YOUR-GDPICTURE-LICENSE-KEY");

        using (GdPicturePDF pdf = new GdPicturePDF())
        {
            GdPictureStatus status = pdf.LoadFromFile("document.pdf", false);

            if (status != GdPictureStatus.OK) return;

            // Save with encryption - many boolean parameters
            status = pdf.SaveToFile(
                "protected.pdf",
                PdfEncryption.PdfEncryption256BitAES,
                "user123",      // User password
                "owner456",     // Owner password
                true,           // Can print
                false,          // Cannot copy
                false,          // Cannot modify
                false,          // Cannot add notes
                true,           // Can fill forms
                false,          // Cannot extract
                false,          // Cannot assemble
                true            // Can print high quality
            );
        }
    }
}

Imports GdPicture14

Class Program
    Shared Sub Main()
        LicenseManager.RegisterKEY("YOUR-GDPICTURE-LICENSE-KEY")

        Using pdf As New GdPicturePDF()
            Dim status As GdPictureStatus = pdf.LoadFromFile("document.pdf", False)

            If status <> GdPictureStatus.OK Then Return

            ' Save with encryption - many boolean parameters
            status = pdf.SaveToFile(
                "protected.pdf",
                PdfEncryption.PdfEncryption256BitAES,
                "user123",      ' User password
                "owner456",     ' Owner password
                True,           ' Can print
                False,          ' Cannot copy
                False,          ' Cannot modify
                False,          ' Cannot add notes
                True,           ' Can fill forms
                False,          ' Cannot extract
                False,          ' Cannot assemble
                True            ' Can print high quality
            )
        End Using
    End Sub
End Class

Imports GdPicture14

Class Program
    Shared Sub Main()
        LicenseManager.RegisterKEY("YOUR-GDPICTURE-LICENSE-KEY")

        Using pdf As New GdPicturePDF()
            Dim status As GdPictureStatus = pdf.LoadFromFile("document.pdf", False)

            If status <> GdPictureStatus.OK Then Return

            ' Save with encryption - many boolean parameters
            status = pdf.SaveToFile(
                "protected.pdf",
                PdfEncryption.PdfEncryption256BitAES,
                "user123",      ' User password
                "owner456",     ' Owner password
                True,           ' Can print
                False,          ' Cannot copy
                False,          ' Cannot modify
                False,          ' Cannot add notes
                True,           ' Can fill forms
                False,          ' Cannot extract
                False,          ' Cannot assemble
                True            ' Can print high quality
            )
        End Using
    End Sub
End Class

After (IronPDF)：

using IronPdf;

class Program
{
    static void Main()
    {
        var pdf = PdfDocument.FromFile("document.pdf");

        // Configure security settings with clear property names
        pdf.SecuritySettings.OwnerPassword = "owner456";
        pdf.SecuritySettings.UserPassword = "user123";

        // Set permissions
        pdf.SecuritySettings.AllowUserPrinting = PdfPrintSecurity.FullPrintRights;
        pdf.SecuritySettings.AllowUserCopyPasteContent = false;
        pdf.SecuritySettings.AllowUserEdits = PdfEditSecurity.NoEdit;
        pdf.SecuritySettings.AllowUserAnnotations = false;
        pdf.SecuritySettings.AllowUserFormData = true;

        pdf.SaveAs("protected.pdf");
    }
}

using IronPdf;

class Program
{
    static void Main()
    {
        var pdf = PdfDocument.FromFile("document.pdf");

        // Configure security settings with clear property names
        pdf.SecuritySettings.OwnerPassword = "owner456";
        pdf.SecuritySettings.UserPassword = "user123";

        // Set permissions
        pdf.SecuritySettings.AllowUserPrinting = PdfPrintSecurity.FullPrintRights;
        pdf.SecuritySettings.AllowUserCopyPasteContent = false;
        pdf.SecuritySettings.AllowUserEdits = PdfEditSecurity.NoEdit;
        pdf.SecuritySettings.AllowUserAnnotations = false;
        pdf.SecuritySettings.AllowUserFormData = true;

        pdf.SaveAs("protected.pdf");
    }
}

Imports IronPdf

Class Program
    Shared Sub Main()
        Dim pdf = PdfDocument.FromFile("document.pdf")

        ' Configure security settings with clear property names
        pdf.SecuritySettings.OwnerPassword = "owner456"
        pdf.SecuritySettings.UserPassword = "user123"

        ' Set permissions
        pdf.SecuritySettings.AllowUserPrinting = PdfPrintSecurity.FullPrintRights
        pdf.SecuritySettings.AllowUserCopyPasteContent = False
        pdf.SecuritySettings.AllowUserEdits = PdfEditSecurity.NoEdit
        pdf.SecuritySettings.AllowUserAnnotations = False
        pdf.SecuritySettings.AllowUserFormData = True

        pdf.SaveAs("protected.pdf")
    End Sub
End Class

Imports IronPdf

Class Program
    Shared Sub Main()
        Dim pdf = PdfDocument.FromFile("document.pdf")

        ' Configure security settings with clear property names
        pdf.SecuritySettings.OwnerPassword = "owner456"
        pdf.SecuritySettings.UserPassword = "user123"

        ' Set permissions
        pdf.SecuritySettings.AllowUserPrinting = PdfPrintSecurity.FullPrintRights
        pdf.SecuritySettings.AllowUserCopyPasteContent = False
        pdf.SecuritySettings.AllowUserEdits = PdfEditSecurity.NoEdit
        pdf.SecuritySettings.AllowUserAnnotations = False
        pdf.SecuritySettings.AllowUserFormData = True

        pdf.SaveAs("protected.pdf")
    End Sub
End Class

IronPDF的SecuritySettings属性提供了命名的、自我记录的属性，而不是位置布尔参数。

关键迁移说明

页面索引转换

此次GdPicture.NET SDK迁移中最重要的变化之一是页面索引的不同：

// GdPicture.NET SDK:1-索引pages
for (int i = 1; i <= pdf.GetPageCount(); i++)
{
    pdf.SelectPage(i);
    // process page
}

// IronPDF: 0-indexed pages (standard .NET)
for (int i = 0; i < pdf.PageCount; i++)
{
    var page = pdf.Pages[i];
    // process page
}

// GdPicture.NET SDK:1-索引pages
for (int i = 1; i <= pdf.GetPageCount(); i++)
{
    pdf.SelectPage(i);
    // process page
}

// IronPDF: 0-indexed pages (standard .NET)
for (int i = 0; i < pdf.PageCount; i++)
{
    var page = pdf.Pages[i];
    // process page
}

' GdPicture.NET SDK:1-索引pages
For i As Integer = 1 To pdf.GetPageCount()
    pdf.SelectPage(i)
    ' process page
Next

' IronPDF: 0-indexed pages (standard .NET)
For i As Integer = 0 To pdf.PageCount - 1
    Dim page = pdf.Pages(i)
    ' process page
Next

' GdPicture.NET SDK:1-索引pages
For i As Integer = 1 To pdf.GetPageCount()
    pdf.SelectPage(i)
    ' process page
Next

' IronPDF: 0-indexed pages (standard .NET)
For i As Integer = 0 To pdf.PageCount - 1
    Dim page = pdf.Pages(i)
    ' process page
Next

状态代码到异常

用标准的 try-catch 代替冗长的状态检查：

// GdPicture.NET SDK
GdPictureStatus status = converter.LoadFromHTMLString(html);
if (status != GdPictureStatus.OK)
{
    Console.WriteLine($"Error: {status}");
    return;
}

// IronPDF
try
{
    var pdf = renderer.RenderHtmlAsPdf(html);
    pdf.SaveAs("output.pdf");
}
catch (Exception ex)
{
    Console.WriteLine($"Error: {ex.Message}");
}

// GdPicture.NET SDK
GdPictureStatus status = converter.LoadFromHTMLString(html);
if (status != GdPictureStatus.OK)
{
    Console.WriteLine($"Error: {status}");
    return;
}

// IronPDF
try
{
    var pdf = renderer.RenderHtmlAsPdf(html);
    pdf.SaveAs("output.pdf");
}
catch (Exception ex)
{
    Console.WriteLine($"Error: {ex.Message}");
}

' GdPicture.NET SDK
Dim status As GdPictureStatus = converter.LoadFromHTMLString(html)
If status <> GdPictureStatus.OK Then
    Console.WriteLine($"Error: {status}")
    Return
End If

' IronPDF
Try
    Dim pdf = renderer.RenderHtmlAsPdf(html)
    pdf.SaveAs("output.pdf")
Catch ex As Exception
    Console.WriteLine($"Error: {ex.Message}")
End Try

' GdPicture.NET SDK
Dim status As GdPictureStatus = converter.LoadFromHTMLString(html)
If status <> GdPictureStatus.OK Then
    Console.WriteLine($"Error: {status}")
    Return
End If

' IronPDF
Try
    Dim pdf = renderer.RenderHtmlAsPdf(html)
    pdf.SaveAs("output.pdf")
Catch ex As Exception
    Console.WriteLine($"Error: {ex.Message}")
End Try

单位转换

GdPicture.NET SDK 使用英寸表示页边距；IronPDF使用毫米：

// GdPicture.NET SDK: 0.5 inches margin
converter.HtmlSetMargins(0.5f, 0.5f, 0.5f, 0.5f);

// IronPDF: 0.5 inches = 12.7 mm
renderer.RenderingOptions.MarginTop = 12.7;
renderer.RenderingOptions.MarginBottom = 12.7;
renderer.RenderingOptions.MarginLeft = 12.7;
renderer.RenderingOptions.MarginRight = 12.7;

// GdPicture.NET SDK: 0.5 inches margin
converter.HtmlSetMargins(0.5f, 0.5f, 0.5f, 0.5f);

// IronPDF: 0.5 inches = 12.7 mm
renderer.RenderingOptions.MarginTop = 12.7;
renderer.RenderingOptions.MarginBottom = 12.7;
renderer.RenderingOptions.MarginLeft = 12.7;
renderer.RenderingOptions.MarginRight = 12.7;

' GdPicture.NET SDK: 0.5 inches margin
converter.HtmlSetMargins(0.5F, 0.5F, 0.5F, 0.5F)

' IronPDF: 0.5 inches = 12.7 mm
renderer.RenderingOptions.MarginTop = 12.7
renderer.RenderingOptions.MarginBottom = 12.7
renderer.RenderingOptions.MarginLeft = 12.7
renderer.RenderingOptions.MarginRight = 12.7

' GdPicture.NET SDK: 0.5 inches margin
converter.HtmlSetMargins(0.5F, 0.5F, 0.5F, 0.5F)

' IronPDF: 0.5 inches = 12.7 mm
renderer.RenderingOptions.MarginTop = 12.7
renderer.RenderingOptions.MarginBottom = 12.7
renderer.RenderingOptions.MarginLeft = 12.7
renderer.RenderingOptions.MarginRight = 12.7

转换公式：millimeters = inches × 25.4

线程安全

GdPicture.NET SDK 需要对并发操作进行手动同步。 IronPDF的ChromePdfRenderer设计上是线程安全的，简化了多线程PDF生成。

性能考虑

重用 ChromePdfRenderer

为获得最佳性能，请重复使用呈现器实例：

// GOOD - Reuse renderer (thread-safe)
public class PdfService
{
    private static readonly ChromePdfRenderer _renderer = new ChromePdfRenderer();

    public byte[] Generate(string html) => _renderer.RenderHtmlAsPdf(html).BinaryData;
}

// BAD - Creates new instance each time
public byte[] GenerateBad(string html)
{
    var renderer = new ChromePdfRenderer();  // Wasteful
    return renderer.RenderHtmlAsPdf(html).BinaryData;
}

// GOOD - Reuse renderer (thread-safe)
public class PdfService
{
    private static readonly ChromePdfRenderer _renderer = new ChromePdfRenderer();

    public byte[] Generate(string html) => _renderer.RenderHtmlAsPdf(html).BinaryData;
}

// BAD - Creates new instance each time
public byte[] GenerateBad(string html)
{
    var renderer = new ChromePdfRenderer();  // Wasteful
    return renderer.RenderHtmlAsPdf(html).BinaryData;
}

Imports System

Public Class PdfService
    Private Shared ReadOnly _renderer As New ChromePdfRenderer()

    Public Function Generate(html As String) As Byte()
        Return _renderer.RenderHtmlAsPdf(html).BinaryData
    End Function

    ' BAD - Creates new instance each time
    Public Function GenerateBad(html As String) As Byte()
        Dim renderer As New ChromePdfRenderer() ' Wasteful
        Return renderer.RenderHtmlAsPdf(html).BinaryData
    End Function
End Class

Imports System

Public Class PdfService
    Private Shared ReadOnly _renderer As New ChromePdfRenderer()

    Public Function Generate(html As String) As Byte()
        Return _renderer.RenderHtmlAsPdf(html).BinaryData
    End Function

    ' BAD - Creates new instance each time
    Public Function GenerateBad(html As String) As Byte()
        Dim renderer As New ChromePdfRenderer() ' Wasteful
        Return renderer.RenderHtmlAsPdf(html).BinaryData
    End Function
End Class

正确的资源处置

// Use using statements for automatic cleanup
using (var pdf = PdfDocument.FromFile("large.pdf"))
{
    string text = pdf.ExtractAllText();
}  // pdf is disposed automatically

// Use using statements for automatic cleanup
using (var pdf = PdfDocument.FromFile("large.pdf"))
{
    string text = pdf.ExtractAllText();
}  // pdf is disposed automatically

Imports PdfDocument

' Use Using blocks for automatic cleanup
Using pdf = PdfDocument.FromFile("large.pdf")
    Dim text As String = pdf.ExtractAllText()
End Using ' pdf is disposed automatically

Imports PdfDocument

' Use Using blocks for automatic cleanup
Using pdf = PdfDocument.FromFile("large.pdf")
    Dim text As String = pdf.ExtractAllText()
End Using ' pdf is disposed automatically