將文檔從一種格式轉換為另一種格式是Spire.PDF的主要功能之一。這種轉換只不過是加載和保存操作的組合。因此，使用Spire.PDF可以將文檔從任何受支持的加載格式轉換為任何受支持的保存格式。

本文整理了包括在C#中以下文件格式的轉換指南，希望對您有所幫助：

• HTML和PDF互轉
  
• 文本轉PDF
  
• 圖像和PDF互轉
  
• XPS和PDF互轉
• PDF轉DOC
  
• PDF轉SVG
  
• PDF轉TIFF
  

>>你可以點擊這里下載Spire.PDF for .NET測試體驗。

（篇幅較長，建議收藏閱讀）

HTML轉換為PDF

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using Spire.Pdf;
using System.Drawing;
using Spire.Pdf.Widget;
using Spire.Pdf.Fields;
using System.Threading;
using Spire.Pdf.HtmlConverter;


namespace PDF
{
    class Program
    {
        static void Main(string[] args)
        {

            //Create a pdf document.
            PdfDocument doc = new PdfDocument();

            PdfPageSettings setting = new PdfPageSettings();

            setting.Size = new SizeF(1000,1000);
            setting.Margins = new Spire.Pdf.Graphics.PdfMargins(20);

            PdfHtmlLayoutFormat htmlLayoutFormat = new PdfHtmlLayoutFormat();
            htmlLayoutFormat.IsWaiting = true;
            
            String url = "http://www.wikipedia.org/";
         
            Thread thread = new Thread(() =>
            { doc.LoadFromHTML(url, false, false, false, setting,htmlLayoutFormat); });
            thread.SetApartmentState(ApartmentState.STA);
            thread.Start();
            thread.Join();
            //Save pdf file.
            doc.SaveToFile("output-wiki.pdf");
            doc.Close();
            //Launching the Pdf file.
            System.Diagnostics.Process.Start("output-wiki.pdf");
        }
    }
}

PDF轉換為HTML

using Spire.Pdf;

namespace ConvertPDFtoHtml
{
    class Program
    {
        static void Main(string[] args)
        {
            PdfDocument pdf = new PdfDocument();
            pdf.LoadFromFile("Test.pdf");

            pdf.SaveToFile("Result.html", FileFormat.HTML);
        }
    }
}

文本轉換為PDF

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Spire.Pdf;
using System.IO;
using Spire.Pdf.Graphics;
using System.Drawing;

namespace TexttoPDF
{
    class Program
    {
        static void Main(string[] args)
        {
            string text = File.ReadAllText("TestDocument.txt");
            PdfDocument doc = new PdfDocument();
            PdfSection section = doc.Sections.Add();
            PdfPageBase page = section.Pages.Add();
            PdfFont font = new PdfFont(PdfFontFamily.Helvetica, 11);
            PdfStringFormat format = new PdfStringFormat();
            format.LineSpacing = 20f;
            PdfBrush brush = PdfBrushes.Black;
            PdfTextWidget textWidget = new PdfTextWidget(text, font, brush);
            float y = 0;
            PdfTextLayout textLayout = new PdfTextLayout();
            textLayout.Break = PdfLayoutBreakType.FitPage;
            textLayout.Layout = PdfLayoutType.Paginate;
            RectangleF bounds = new RectangleF(new PointF(0, y), page.Canvas.ClientSize);
            textWidget.StringFormat = format;
            textWidget.Draw(page, bounds, textLayout);
            doc.SaveToFile("TxtToPDf.pdf", FileFormat.PDF);
        }
    }

圖像轉換為PDF

//save and launch the file
doc.SaveToFile("image to pdf.pdf");
doc.Close();
System.Diagnostics.Process.Start("image to pdf.pdf");

PDF轉換為圖像

using Spire.Pdf;
using System.Drawing;
using System.Drawing.Imaging;

namespace PDFtoImage
{
    class Program
    {
        static void Main(string[] args)
        {
            PdfDocument doc = new PdfDocument();
            doc.LoadFromFile("sample.pdf");
            Image bmp = doc.SaveAsImage(0);
            Image emf = doc.SaveAsImage(0, Spire.Pdf.Graphics.PdfImageType.Metafile);
            Image zoomImg = new Bitmap((int)(emf.Size.Width * 2), (int)(emf.Size.Height * 2));
            using (Graphics g = Graphics.FromImage(zoomImg))
            {
                g.ScaleTransform(2.0f, 2.0f);
                g.DrawImage(emf, new Rectangle(new Point(0, 0), emf.Size), new Rectangle(new Point(0, 0), emf.Size), GraphicsUnit.Pixel);
            }
            bmp.Save("convertToBmp.bmp", ImageFormat.Bmp);
            System.Diagnostics.Process.Start("convertToBmp.bmp");
            emf.Save("convertToEmf.png", ImageFormat.Png);
            System.Diagnostics.Process.Start("convertToEmf.png");
            zoomImg.Save("convertToZoom.png", ImageFormat.Png);
            System.Diagnostics.Process.Start("convertToZoom.png");

        }
    }
}

XPS轉換為PDF

doc.SaveToFile(pdfFile, FileFormat.PDF);

PDF轉換為XPS

using System;
using System.Collections.Generic;
using System.Text;
using Spire.Pdf;

namespace ConvertPdfToXps
{
    class Program
    {
        static void Main(string[] args)
        {
            //  Instatate an object of Spire.Pdf.PdfDocument
            PdfDocument doc = new PdfDocument();
            // Load PDF document 
            doc.LoadFromFile("sample.pdf");
            // Save it to XPS format 
            doc.SaveToFile("sample.xps", FileFormat.XPS);
            doc.Close();
            System.Diagnostics.Process.Start("sample.xps");
        }
    }
}

PDF轉換為DOC

using Spire.Pdf;

namespace ConvertPDFtoDoc
{
    class Program
    {
        static void Main(string[] args)
        {
            PdfDocument doc = new PdfDocument();
            doc.LoadFromFile("test.pdf");
            doc.SaveToFile("PDFtoDoc.doc", FileFormat.DOC);
            System.Diagnostics.Process.Start("PDFtoDoc.doc");
        }
    }
}

PDF轉換為SVG

using Spire.Pdf;

namespace Convert_PDF_to_SVG
{
    class Program
    {
        static void Main(string[] args)
        {
            PdfDocument document = new PdfDocument();
            document.LoadFromFile("Test.pdf");

            document.SaveToFile(@"E:\Program Files\Result.svg", FileFormat.SVG);
        }
    }
}

PDF轉換為TIFF

using System;
using System.Drawing;
using System.Drawing.Imaging;
using Spire.Pdf;
namespace SavePdfAsTiff
{
    class Program
    {
        static void Main(string[] args)
        {
            PdfDocument document = new PdfDocument();
            document.LoadFromFile(@"01.pdf");
    JoinTiffImages(SaveAsImage(document),"result.tiff",EncoderValue.CompressionLZW);
            System.Diagnostics.Process.Start("result.tiff");
        }
        private static Image[] SaveAsImage(PdfDocument document)
        {
            Image[] images = new Image[document.Pages.Count];
            for (int i = 0; i < document.Pages.Count; i++)
            {
                images[i] = document.SaveAsImage(i);
            }
            return images;
        }

        private static ImageCodecInfo GetEncoderInfo(string mimeType)
        {
            ImageCodecInfo[] encoders = ImageCodecInfo.GetImageEncoders();
            for (int j = 0; j < encoders.Length; j++)
            {
                if (encoders[j].MimeType == mimeType)
                    return encoders[j];
            }
            throw new Exception(mimeType + " mime type not found in ImageCodecInfo");
        }

        public static void JoinTiffImages(Image[] images, string outFile, EncoderValue compressEncoder)
        {
            //use the save encoder
            Encoder enc = Encoder.SaveFlag;
            EncoderParameters ep = new EncoderParameters(2);
            ep.Param[0] = new EncoderParameter(enc, (long)EncoderValue.MultiFrame);
            ep.Param[1] = new EncoderParameter(Encoder.Compression, (long)compressEncoder);
            Image pages = images[0];
            int frame = 0;
            ImageCodecInfo info = GetEncoderInfo("image/tiff");
            foreach (Image img in images)
            {
                if (frame == 0)
                {
                    pages = img;
                    //save the first frame
                    pages.Save(outFile, info, ep);
                }

                else
                {
                    //save the intermediate frames
                    ep.Param[0] = new EncoderParameter(enc, (long)EncoderValue.FrameDimensionPage);

                    pages.SaveAdd(img, ep);
                }
                if (frame == images.Length - 1)
                {
                    //flush and close.
                    ep.Param[0] = new EncoderParameter(enc, (long)EncoderValue.Flush);
                    pages.SaveAdd(ep);
                }
                frame++;
            }
        }
    }
}