如何使用 WaitFor 來延遲 C# PDF 渲染

# Remove whichever PDFium wrapper you used:
#   PdfiumViewer            (Apache 2.0 - archived 2019, .NET Framework only)
#   PdfiumViewer.Updated    (community fork, .NET Core / .NET 6)
#   PDFiumCore              (Dtronix - .NET Standard 2.1 P/Invoke bindings)
#   Pdfium.Net.SDK          (Patagames - commercial, perpetual license)
dotnet remove package PdfiumViewer
dotnet remove package PdfiumViewer.Updated
dotnet remove package PDFiumCore
dotnet remove package Pdfium.Net.SDK

# Install IronPDF
dotnet add package IronPdf

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

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

# Find PDFium wrapper usage
grep -rE "PdfiumViewer|PDFiumCore|Patagames\.Pdf|PdfDocument\.Load|\.Render\(" --include="*.cs" .

# Find native binary references
grep -rE "pdfium\.dll|libpdfium\.(so|dylib)" --include="*.csproj" --include="*.config" .

# Find platform-specific code
grep -rE "#if.*64|WIN32|WIN64|LINUX|OSX" --include="*.cs" .

// PDFium wrappers (use the one you installed)
using PdfiumViewer;             // PdfiumViewer / PdfiumViewer.Updated
using PDFiumCore;               // Dtronix PDFiumCore (P/Invoke bindings)
using Patagames.Pdf;            // Patagames Pdfium.Net.SDK
using Patagames.Pdf.Net;        // Patagames Pdfium.Net.SDK

// IronPDF
using IronPdf;
using IronPdf.Rendering;
using IronPdf.Editing;

Imports PdfiumViewer ' PdfiumViewer / PdfiumViewer.Updated
Imports PDFiumCore ' Dtronix PDFiumCore (P/Invoke bindings)
Imports Patagames.Pdf ' Patagames Pdfium.Net.SDK
Imports Patagames.Pdf.Net ' Patagames Pdfium.Net.SDK

Imports IronPdf
Imports IronPdf.Rendering
Imports IronPdf.Editing

// NuGet: Install-Package PdfiumViewer  (Apache 2.0； archived Aug 2019, .NET Framework 2.0+)
//        or Install-Package PdfiumViewer.Updated  (maintained fork, .NET Core / .NET 6)
//        or Install-Package PDFiumCore             (Dtronix, .NET Standard 2.1 P/Invoke)
//        or Install-Package Pdfium.Net.SDK         (Patagames, commercial perpetual license)
using PdfiumViewer;
using System;
using System.IO;
using System.Text;

class Program
{
    static void Main()
    {
        string pdfPath = "document.pdf";

        using (var document = PdfDocument.Load(pdfPath))
        {
            StringBuilder text = new StringBuilder();

            for (int i = 0; i < document.PageCount; i++)
            {
                // PdfiumViewer's text extraction is per-page raw text via GetPdfText(int).
                // No layout / format metadata is exposed.
                string pageText = document.GetPdfText(i);
                text.AppendLine(pageText);
            }

            Console.WriteLine(text.ToString());
        }
    }
}

Imports PdfiumViewer
Imports System
Imports System.IO
Imports System.Text

Module Program
    Sub Main()
        Dim pdfPath As String = "document.pdf"

        Using document = PdfDocument.Load(pdfPath)
            Dim text As New StringBuilder()

            For i As Integer = 0 To document.PageCount - 1
                ' PdfiumViewer's text extraction is per-page raw text via GetPdfText(int).
                ' No layout / format metadata is exposed.
                Dim pageText As String = document.GetPdfText(i)
                text.AppendLine(pageText)
            Next

            Console.WriteLine(text.ToString())
        End Using
    End Sub
End Module

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

class Program
{
    static void Main()
    {
        IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

        string pdfPath = "document.pdf";

        var pdf = PdfDocument.FromFile(pdfPath);
        string text = pdf.ExtractAllText();

        Console.WriteLine(text);
    }
}

Imports IronPdf
Imports System

Class Program
    Shared Sub Main()
        IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY"

        Dim pdfPath As String = "document.pdf"

        Dim pdf = PdfDocument.FromFile(pdfPath)
        Dim text As String = pdf.ExtractAllText()

        Console.WriteLine(text)
    End Sub
End Class

// NuGet: Install-Package PdfiumViewer  (representative open-source PDFium wrapper)
// PdfiumViewer and PDFiumCore do not expose PDF merge APIs - PDFium itself
// is a rendering / parsing engine, not a document-authoring engine.
// (Patagames Pdfium.Net.SDK exposes some document-edit operations but is commercial.)
using PdfiumViewer;
using System;
using System.IO;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        List<string> pdfFiles = new List<string>
        {
            "document1.pdf",
            "document2.pdf",
            "document3.pdf"
        };

        // To merge PDFs from a PDFium wrapper you must reach for another library
        // (PdfSharp, iText, IronPDF) or, with Patagames Pdfium.Net.SDK, use its
        // document-edit APIs.

        Console.WriteLine("PDF merging is not supported by PdfiumViewer / PDFiumCore.");
    }
}

Imports PdfiumViewer
Imports System
Imports System.IO
Imports System.Collections.Generic

Module Program
    Sub Main()
        Dim pdfFiles As New List(Of String) From {
            "document1.pdf",
            "document2.pdf",
            "document3.pdf"
        }

        ' To merge PDFs from a PDFium wrapper you must reach for another library
        ' (PdfSharp, iText, IronPDF) or, with Patagames Pdfium.Net.SDK, use its
        ' document-edit APIs.

        Console.WriteLine("PDF merging is not supported by PdfiumViewer / PDFiumCore.")
    End Sub
End Module

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

class Program
{
    static void Main()
    {
        IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

        List<string> pdfFiles = new List<string>
        {
            "document1.pdf",
            "document2.pdf",
            "document3.pdf"
        };

        // PdfDocument.Merge accepts an IEnumerable<PdfDocument>, so load each file first.
        var docs = pdfFiles.Select(path => PdfDocument.FromFile(path)).ToList();
        var merged = PdfDocument.Merge(docs);
        merged.SaveAs("merged.pdf");

        Console.WriteLine("PDFs merged successfully");
    }
}

Imports IronPdf
Imports System
Imports System.Collections.Generic
Imports System.Linq

Module Program
    Sub Main()
        IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY"

        Dim pdfFiles As New List(Of String) From {
            "document1.pdf",
            "document2.pdf",
            "document3.pdf"
        }

        ' PdfDocument.Merge accepts an IEnumerable(Of PdfDocument), so load each file first.
        Dim docs = pdfFiles.Select(Function(path) PdfDocument.FromFile(path)).ToList()
        Dim merged = PdfDocument.Merge(docs)
        merged.SaveAs("merged.pdf")

        Console.WriteLine("PDFs merged successfully")
    End Sub
End Module

// NuGet: Install-Package PdfiumViewer  (representative PDFium wrapper)
// PDFium is a PDF rendering / parsing engine. It has NO HTML parser, so no
// PDFium .NET wrapper (PdfiumViewer, PdfiumViewer.Updated, PDFiumCore,
// Pdfium.Net.SDK) can convert HTML to PDF on its own.
using PdfiumViewer;
using System;
using System.IO;
using System.Drawing.Printing;

class Program
{
    static void Main()
    {
        // PDFium has no native HTML-to-PDF capability.
        // Produce the PDF with another engine (wkhtmltopdf, headless Chromium,
        // IronPDF, etc.) and then load it with PdfDocument.Load(...) for rendering.
        string htmlContent = "<h1>Hello World</h1>";

        Console.WriteLine("HTML to PDF conversion is not supported by PDFium.");
    }
}

Imports PdfiumViewer
Imports System
Imports System.IO
Imports System.Drawing.Printing

Module Program
    Sub Main()
        ' PDFium has no native HTML-to-PDF capability.
        ' Produce the PDF with another engine (wkhtmltopdf, headless Chromium,
        ' IronPDF, etc.) and then load it with PdfDocument.Load(...) for rendering.
        Dim htmlContent As String = "<h1>Hello World</h1>"

        Console.WriteLine("HTML to PDF conversion is not supported by PDFium.")
    End Sub
End Module

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

class Program
{
    static void Main()
    {
        IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

        var renderer = new ChromePdfRenderer();
        string htmlContent = "<h1>Hello World</h1>";

        var pdf = renderer.RenderHtmlAsPdf(htmlContent);
        pdf.SaveAs("output.pdf");

        Console.WriteLine("PDF created successfully");
    }
}

Imports IronPdf
Imports System

Module Program
    Sub Main()
        IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY"

        Dim renderer As New ChromePdfRenderer()
        Dim htmlContent As String = "<h1>Hello World</h1>"

        Dim pdf = renderer.RenderHtmlAsPdf(htmlContent)
        pdf.SaveAs("output.pdf")

        Console.WriteLine("PDF created successfully")
    End Sub
End Module

# Delete native PDFium binaries
rm -rf x86/x64/runtimes/

# Remove from .csproj
# Delete any <Content Include="pdfium.dll" /> entries
# Delete any <None Include="x86/pdfium.dll" /> entries

// Formula:IronPDFDPI = 72 × PDFium scale
// PDFium scale 2.0 →IronPDFDPI 144
pdf.RasterizeToImageFiles("*.png", DPI: 144);

' Formula: IronPDFDPI = 72 × PDFium scale
' PDFium scale 2.0 → IronPDFDPI 144
pdf.RasterizeToImageFiles("*.png", DPI:=144)

// PdfiumViewer
PdfDocument.Load(path)

// IronPDF
PdfDocument.FromFile(path)

' PdfiumViewer
PdfDocument.Load(path)

' IronPDF
PdfDocument.FromFile(path)

// PdfiumViewer (takes a Stream)
document.Save(stream)

//IronPDF(takes a path)
pdf.SaveAs(path)

// PdfiumViewer: explicit disposal of document and the rendered Image
using (var document = PdfDocument.Load(path))
using (var bitmap = document.Render(0, 1024, 768, 96, 96, PdfRenderFlags.None))
{
    bitmap.Save("output.png");
}

// IronPDF: Simplified
var pdf = PdfDocument.FromFile(path);
pdf.RasterizeToImageFiles("output.png");

Imports PdfiumViewer

' PdfiumViewer: explicit disposal of document and the rendered Image
Using document = PdfDocument.Load(path)
    Using bitmap = document.Render(0, 1024, 768, 96, 96, PdfRenderFlags.None)
        bitmap.Save("output.png")
    End Using
End Using

' IronPDF: Simplified
Dim pdf = PdfDocument.FromFile(path)
pdf.RasterizeToImageFiles("output.png")

// PDFium wrapper: required platform detection / RID-specific binaries
#if WIN64
    // Load x64 pdfium.dll
#else
    // Load x86 pdfium.dll
#endif

// IronPDF: Remove all platform-specific code
// Just use the API directly