生成PDF文档我们通常可以通过文档转换的形式来得到想要的PDF，但我们也可以通过最直接的方式来创建PDF文档，由此本篇文章将介绍C#如何来创建带图、文元素的PDF文档。同理，对于需要读取PDF文档的情况，我们也可以分情况来读取想要的文档元素（文本、图片）。在下面的示例中将做详细介绍。
示例要点梳理：
一、创建PDF文档（可支持中文）
1.写入文本（包括页边距、字体、字号等设置）
2.绘入图片
二、读取PDF文档
1.读取文本
1.1读取全部文本
1.2读取指定区域文本
2.读取图片
使用工具：Free Spire.PDF for .NET4.3 (最新免费版)
注：在编辑代码前引用Spire.PDF.dll，dll文件可在安装路径下的Bin文件夹中获取。
一、创建PDF文档
C#
using Spire.Pdf;
using Spire.Pdf.Graphics;
using System.Drawing;
namespace CreatePDF_PDF
{
class Program
{
static void Main(string[] args)
{
//初始化一个PdfDocument类实例
PdfDocument document = new PdfDocument();
//声明 PdfUnitConvertor和PdfMargins类对象
PdfUnitConvertor unitCvtr = new PdfUnitConvertor();
PdfMargins margins = new PdfMargins();
//设置页边距
margins.Top = unitCvtr.ConvertUnits(2.54f, PdfGraphicsUnit.Centimeter, PdfGraphicsUnit.Point);
margins.Bottom = margins.Top;
margins.Left = unitCvtr.ConvertUnits(3.17f, PdfGraphicsUnit.Centimeter, PdfGraphicsUnit.Point);
margins.Right = margins.Left;
//新添加一个A4大小的页面
PdfPageBase page = document.Pages.Add(PdfPageSize.A4, margins);
//自定义PdfTrueTypeFont、PdfPen实例，设置字体类型、字号和字体颜色
PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("楷体", 11f),true);
PdfPen pen = new PdfPen(Color.Black);
//调用DrawString()方法在指定位置写入文本
string text = ("《蝶恋花 送春》 \n 楼外垂杨千万缕，欲系青春，少住春还去。犹自风前飘柳絮，随春且看归何处？\n 绿满山川闻杜宇，便作无情，莫也愁人苦。把酒送春春不语，黄昏却下潇潇雨。");
page.Canvas.DrawString(text, font, pen, 15, 13);
//加载图片，并调用DrawImage()方法在指定位置绘入图片
PdfImage image = PdfImage.FromFile("image1.jpg");
float width = image.Width * 0.55f;
float height = image.Height * 0.55f;
float y = (page.Canvas.ClientSize.Width - width) / 3;
page.Canvas.DrawImage(image, y, 60, width, height);
//保存并打开文档
document.SaveToFile("PDF创建.pdf");
System.Diagnostics.Process.Start("PDF创建.pdf");
}
}
}
创建结果：
VB.NET
Imports Spire.Pdf
Imports Spire.Pdf.Graphics
Imports System.Drawing
Namespace CreatePDF_PDF
Class Program
Private Shared Sub Main(ByVal args As String())
Dim document As PdfDocument = New PdfDocument()
Dim unitCvtr As PdfUnitConvertor = New PdfUnitConvertor()
Dim margins As PdfMargins = New PdfMargins()
margins.Top = unitCvtr.ConvertUnits(2.54F, PdfGraphicsUnit.Centimeter, PdfGraphicsUnit.Point)
margins.Bottom = margins.Top
margins.Left = unitCvtr.ConvertUnits(3.17F, PdfGraphicsUnit.Centimeter, PdfGraphicsUnit.Point)
margins.Right = margins.Left
Dim page As PdfPageBase = document.Pages.Add(PdfPageSize.A4, margins)
Dim font As PdfTrueTypeFont = New PdfTrueTypeFont(New Font("楷体", 11F), True)
Dim pen As PdfPen = New PdfPen(Color.Black)
Dim text As String =("《蝶恋花 送春》 " & vbLf & " 楼外垂杨千万缕，欲系青春，少住春还去。犹自风前飘柳絮，随春且看归何处？" & vbLf & " 绿满山川闻杜宇，便作无情，莫也愁人苦。把酒送春春不语，黄昏却下潇潇雨。")
page.Canvas.DrawString(text, font, pen, 15, 13)
Dim image As PdfImage = PdfImage.FromFile("image1.jpg")
Dim width As Single = image.Width * 0.55F
Dim height As Single = image.Height * 0.55F
Dim y As Single =(page.Canvas.ClientSize.Width - width) / 3
page.Canvas.DrawImage(image, y, 60, width, height)
document.SaveToFile("PDF创建.pdf")
System.Diagnostics.Process.Start("PDF创建.pdf")
End Sub
End Class
End Namespace这里创建PDF文档，Spire.PDF支持直接生成PDF文档并同时实现添加文本、图片、图形、水印、表格、页眉页脚、页码等操作，这里示例代码以添加文本、图片为例，有需要可以参见以下博客：
- C# 添加PDF水印
- C# 创建PDF表格
二、 读取PDF文档
测试文档：
1. 读取PDF文本
1.1读取全部文本
C#
using Spire.Pdf;
using System;
using System.IO;
using System.Text;
namespace ExtractText_PDF
{
class Program
{
static void Main(string[] args)
{
//实例化PdfDocument类对象，并加载PDF文档
PdfDocument doc = new PdfDocument();
doc.LoadFromFile("sample.pdf");
//实例化一个StringBuilder 对象
StringBuilder content = new StringBuilder();
//遍历文档所有PDF页面，提取文本
foreach (PdfPageBase page in doc.Pages)
{
content.Append(page.ExtractText());
}
//将提取到的文本写为.txt格式并保存到本地路径
String fileName = "获取文本.txt";
File.WriteAllText(fileName, content.ToString());
System.Diagnostics.Process.Start("获取文本.txt");
}
}
}
读取结果：
VB.NET
Imports Spire.Pdf
Imports System
Imports System.IO
Imports System.Text
Namespace ExtractText_PDF
Class Program
Private Shared Sub Main(ByVal args As String())
Dim doc As PdfDocument = New PdfDocument()
doc.LoadFromFile("sample.pdf")
Dim content As StringBuilder = New StringBuilder()
For Each page As PdfPageBase In doc.Pages
content.Append(page.ExtractText())
Next
Dim fileName As String = "获取文本.txt"
File.WriteAllText(fileName, content.ToString())
System.Diagnostics.Process.Start("获取文本.txt")
End Sub
End Class
End Namespace1.2 读取指定区域文本
C#
using Spire.Pdf;
using System.IO;
using System.Text;
using System.Drawing;
namespace ExtractText1_PDF
{
class Program
{
static void Main(string[] args)
{
//创建PdfDocument类实例，并加载PDF文档
PdfDocument pdf = new PdfDocument();
pdf.LoadFromFile("sample.pdf");
//获取PDF第一页
PdfPageBase page = pdf.Pages[0];
//从第一页的指定矩形区域内提取文本
string text = page.ExtractText(new RectangleF(50, 50, 500, 170));
//保存文本到.txt文件，并打开文档
StringBuilder sb = new StringBuilder();
sb.AppendLine(text);
File.WriteAllText("Extract.txt", sb.ToString());
System.Diagnostics.Process.Start("Extract.txt");
}
}
}
读取结果：
（此时读取的就只是指定区域内的文本）
VB.NET
Imports Spire.Pdf
Imports System.IO
Imports System.Text
Imports System.Drawing
Namespace ExtractText1_PDF
Class Program
Private Shared Sub Main(ByVal args As String())
Dim pdf As PdfDocument = New PdfDocument()
pdf.LoadFromFile("sample.pdf")
Dim page As PdfPageBase = pdf.Pages(0)
Dim text As String = page.ExtractText(New RectangleF(50, 50, 500, 170))
Dim sb As StringBuilder = New StringBuilder()
sb.AppendLine(text)
File.WriteAllText("Extract.txt", sb.ToString())
System.Diagnostics.Process.Start("Extract.txt")
End Sub
End Class
End Namespace2. 读取PDF图片
C#
using Spire.Pdf;
using System.Collections.Generic;
using System.Drawing;
namespace ExtractImages_PDF
{
class Program
{
static void Main(string[] args)
{
//创建一个PdfDocument类对象，加载PDF测试文档
PdfDocument doc = new PdfDocument();
doc.LoadFromFile("sample.pdf");
//声明List类对象
List ListImage = new List();
//遍历PDF文档所有页面
for (int i = 0; i < doc.Pages.Count; i++)
{
//获取文档所有页，并提取页面中的所有图片
PdfPageBase page = doc.Pages[i];
Image[] images = page.ExtractImages();
if (images != null && images.Length > 0)
{
ListImage.AddRange(images);
}
}
//将获取到的图片保存到本地路径
if (ListImage.Count > 0)
{
for (int i = 0; i < ListImage.Count; i++)
{
Image image = ListImage[i];
image.Save("image" + (i + 1).ToString() + ".png", System.Drawing.Imaging.ImageFormat.Png);
}
//打开获取到的图片
System.Diagnostics.Process.Start("image1.png");
}
}
}
}
读取结果：
VB.NET
Imports Spire.Pdf
Imports System.Collections.Generic
Imports System.Drawing
Namespace ExtractImages_PDF
Class Program
Private Shared Sub Main(ByVal args As String())
Dim doc As PdfDocument = New PdfDocument()
doc.LoadFromFile("sample.pdf")
Dim ListImage As List(Of Image) = New List(Of Image)()
For i As Integer = 0 To doc.Pages.Count - 1
Dim page As PdfPageBase = doc.Pages(i)
Dim images As Image() = page.ExtractImages()
If images IsNot Nothing AndAlso images.Length > 0 Then
ListImage.AddRange(images)
End If
Next
If ListImage.Count > 0 Then
For i As Integer = 0 To ListImage.Count - 1
Dim image As Image = ListImage(i)
image.Save("image" & (i + 1).ToString() & ".png", System.Drawing.Imaging.ImageFormat.Png)
Next
System.Diagnostics.Process.Start("image1.png")
End If
End Sub
End Class
End Namespace