在.NET中使用iTextSharp建立/讀取PDF報告： Part I [翻譯]

時間 2019-11-12

標籤使用 itextsharp 建立讀取 pdf 報告翻譯简体版

原文原文鏈接

原文地址：Create/Read Advance PDF Report using iTextSharp in C# .NET: Part I By Debopam Pal, 27 Nov 2013html

到PDF原文介紹了iTextSharp這個類庫，並演示了一些基本的操做，基本屬於入門級別的，惋惜做者並無在編寫後續的文章。java

剛好本身也在學習這個類庫，想實現一個導出ASPX頁面到PDF的功能，如做者所說，網上找到的示例好多都是針對舊版本iTextSharp編寫的，還有些驢脣不對馬嘴，並且，不少照抄的連驗證都省了，一點價值都沒有。這篇文章算是詳實的入門文章，實例也都基本操做了一遍實現沒有問題。c#

ps.：第一次翻譯老外的文章，英語水平通常，有些地方詞不達意，還望海涵，若是出入但願幫忙指出。api

文章內容

簡介

最近我一直在尋找一個高級的工具來建立複雜的PDF報告用在C#.NET中，我找到了iTextSharp.主要的問題是iTextSharp.缺少文檔。好吧，有少許的C#代碼例子，可是那些對初學者來講是不夠的而且這些示例代碼都是創建在iTextSharp的舊版本上，在最新版本上有不少變化。因此，對初學者來講轉換舊版本到新版本比較困難。此外，我認爲假如我寫一篇關於iTextSharp的文章，它能幫助我同時也能做爲往後的參考，我將爲每個功能點書寫示例。老實說，在這篇文章，我編寫的全部示例，你都能在《iText in Action, Second Edition》這本書的第一節找到，這本書是針對Java開發者編寫的。我將在個人文章中解釋[從java到c#]這本書餘下章節的全部的示例.因此，若是有人對這個庫(iTextSharp)感興趣，這裏將是一個好的開始。ruby

想知道關於(iTextSharp)的更多細節，能夠經過他們的官方網站瞭解app

要求

編譯這個類庫，你須要一個C#2008(vs2008)編譯器或者更高版本，Visual Studio 2008 or Visual C# 2008 Express Edition
這個庫代碼運行在:
- .NET 2.0
- .NET 3.0
- .NET 3.5
- .NET 4.0
- .NET 4.0 Client Profile
- .NET 4.5
- .NET 4.5 Client Profile

安裝

你須要安裝 NuGet package

或者你能夠從下面這個SourceForge的連接下載DLL，而後參照下面步驟:ide

添加引用BlahBlah(步驟以下，翻譯掠過). Just see the image below:
你須要引入到C#文件中的命名空間:
- iTextSharp.text
- iTextSharp.text.pdf

快速入門

6步建立一個PDF文檔:

Step 1: 建立一個 System.IO.FileStream 對象:

FileStream fs = new FileStream("Chapter1_Example1.pdf", FileMode.Create, FileAccess.Write, FileShare.None);

Step 2: 建立一個 iTextSharp.text.Document 對象:

Document doc = new Document();

Step 3: 建立一個 iTextSharp.text.pdf.PdfWriter 對象: 它有助於把Document書寫到特定的FileStream:

PdfWriter writer = PdfWriter.GetInstance(doc, fs);

Step 4: 打開 Document:

doc.Open();

Step 5: 建立一個 iTextSharp.text.Paragraph 對象並添加到Document裏:

doc.Add(new Paragraph("Hello World"));

Step 6: 關閉 Document:

doc.Close();

關聯PDF文檔的頁面大小:

建立一個特定大小的頁面，咱們須要建立一個iTextSharp.text.Rectangle 對象同時傳遞一個頁面大小的參數到它的構造函數裏面，下面是定義頁面大小的方法:函數

第一種定義一個版面大小的方式:
經過定義像素或者英寸定義一個頁面尺寸。注意：在iTextSharp裏面頁面大小的單位是‘point。72point=1英寸。假設咱們須要一個寬度=2英寸&高度=10英寸的PDF文件，那麼咱們須要144pt&72pt，讓咱們看下該怎麼作:

Rectangle rec = new Rectangle(144, 720);

第二種定義版面大小的方式:
使用內建的 iTextSharp.text.PageSize 類定義:
```
Rectangle rec2 = new Rectangle(PageSize.A4);
```
下面是內建的版面大小。. 完整的頁面大小說明連接 Documentation of Page Size:
- _11X17
- A0
- A1
- A10
- A2
- A3
- A4
- A4_LANDSCAPE
- A5
- A6
- A7
- A8
- A9
- ARCH_A
- ARCH_B
- ARCH_C
- ARCH_D
- ARCH_E
- B0
- B1
- B10
- B2
- B3
- B4
- B5
- B6
- B7
- B8
- B9
- CROWN_OCTAVO
- CROWN_QUARTO
- DEMY_OCTAVO
- DEMY_QUARTO
- EXECUTIVE
- FLSA
- FLSE
- HALFLETTER
- ID_1
- ID_2
- ID_3
- LARGE_CROWN_OCTAVO
- LARGE_CROWN_QUARTO
- LEDGER
- LEGAL
- LEGAL_LANDSCAPE
- LETTER
- LETTER_LANDSCAPE
- NOTE
- PENGUIN_LARGE_PAPERBACK
- PENGUIN_SMALL_PAPERBACK
- POSTCARD
- ROYAL_OCTAVO
- ROYAL_QUARTO
- SMALL_PAPERBACK
- TABLOID
第三種定義版面大小的方式:
反轉文檔的高度變成寬度&反之亦然:
```
Rectangle rec3 = new Rectangle(PageSize.A4.Rotate());
```

如今，把剛剛的這個 iTextSharp.text.Rectangle 對象 (任意一個)也就是上面的 'rec',或者 'rec2'或者 'rec3'加入iTextSharp.text.Document's 的構造函數中:工具

Document doc = new Document(rec);

設置PDF文檔背景色:

有幾種方式來設置背景色:oop

第一種方法:
須要使用對象 iTextSharp.text.BaseColor. 實例化BaseColor 採用System.Drawing.Color （.NET）對象或者你也能夠用傳遞RGB值的形式來定義:
```
rec.BackgroundColor = new BaseColor(System.Drawing.Color.WhiteSmoke);
```
第二種方法:
須要使用對象 iTextSharp.text.pdf.CMYKColor. CMYKColor 經過傳遞 CMYK 值的方式來構造:
```
rec2.BackgroundColor = new CMYKColor(25, 90, 25, 0);
```

設置PDF文檔邊距:

頁邊距能夠像設置版面大小同樣來定義
加入咱們設置以下的頁邊距:

Left : 0.5 inch
Right : 1 inch
Top : 1.5 inch
Bottom : 2.5 inch

因此咱們須要分別設置頁面的 Left, Right, Top, Bottom 頁邊距使用point單位，由於咱們知道 iTextSharp 中是使用point做爲單位的，而且 72 points = 1 inch.

Left : 36pt => 0.5 inch
Right : 72pt => 1 inch
Top : 108pt => 1.5 inch
Bottom : 180pt => 2.5 inch

實現以下:

Document doc = new Document(PageSize.A4, 36, 72, 108, 180);

設置PDF文檔文字對齊方式:

Alignment 是iTextSharp.text.Paragraph對象的屬性. iTextSharp 提供了各類對齊方式. 能夠經過iTextSharp.text.Element 類設置對其.如下是iTextSharp提供的對齊方式:

咱們已經知道在 iTextSharp.text.Document 的構造函數中須要iTextSharp.text.Paragraph 對象，因此在建立Paragraph對象之後咱們能夠設置它的對齊方式，咱們能夠在Document建立過程把Prargraph傳遞進去.

實現以下:

Paragraph para = new Paragraph("Hello World Hello World Hello World Hello World Hello World Hello World Hello World Hello World Hello World Hello World Hello World");
// Setting paragraph's text alignment using iTextSharp.text.Element class
para.Alignment = Element.ALIGN_JUSTIFIED;
// Adding this 'para' to the Document object
doc.Add(para);

設置PDF文檔的元信息或屬性:

下面這些PDF文檔的元信息你能夠經過iTextSharp.text.Document建立的對象doc(上文的doc)裏面的方法來設置:

Author Name[^]
Creation Date[^]
Creator Name[^]
Header Name & Content[^]
Keywords[^]
Langugae[^]
Producer[^]
Subject[^]
Title[^]

下面是他們的一些實現:

// Setting Document properties e.g.
// 1. Title
// 2. Subject
// 3. Keywords
// 4. Creator
// 5. Author
// 6. Header
doc.AddTitle("Hello World example");
doc.AddSubject("This is an Example 4 of Chapter 1 of Book 'iText in Action'");
doc.AddKeywords("Metadata, iTextSharp 5.4.4, Chapter 1, Tutorial");
doc.AddCreator("iTextSharp 5.4.4");
doc.AddAuthor("Debopam Pal");
doc.AddHeader("Nothing", "No Header");

如今，打開一個PDF文檔後，右鍵->屬性，你會看到剛纔設置的信息:

建立多頁文檔:

咱們能夠經過iTextSharp.text.Document的NewPage()方法建立新頁面，咱們來建立5個PDF文檔(頁面) :

for (int i = 1; i <= 5; i++)
{
    doc.NewPage();
    doc.Add(new Paragraph(string.Format("This is a page {0}", i)));
}

從已有文檔建立新的PDF文檔:

咱們可使用iTextSharp.text.pdf.PdfReader對象讀取一個PDF文檔，而後使用 iTextSharp.text.pdf.PdfStamper對象來把它寫到另外一個PDF文檔。實現以下:

string originalFile = "Original.pdf";
string copyOfOriginal = "Copy.pdf";
using (FileStream fs = new FileStream(originalFile, FileMode.Create, FileAccess.Write, FileShare.None))
using (Document doc = new Document(PageSize.LETTER))
using (PdfWriter writer = PdfWriter.GetInstance(doc, fs))
{
    doc.Open();
    doc.Add(new Paragraph("Hi! I'm Original"));
    doc.Close();
}
PdfReader reader = new PdfReader(originalFile);
using (FileStream fs = new FileStream(copyOfOriginal, FileMode.Create, FileAccess.Write, FileShare.None))
// Creating iTextSharp.text.pdf.PdfStamper object to write
// Data from iTextSharp.text.pdf.PdfReader object to FileStream object
using (PdfStamper stamper = new PdfStamper(reader, fs)) { }

使用Layer爲PDF文檔添加水印:

再iTextSharp中，PDF文檔建立後能夠添加水印，在這裏我將使用iTextSharp.text.pdf.PdfLayer爲已有的PDF文檔（Original.pdf）添加水印。實現以下:

string watermarkedFile = "Watermarked.pdf";
// Creating watermark on a separate layer
// Creating iTextSharp.text.pdf.PdfReader object to read the Existing PDF Document
PdfReader reader1 = new PdfReader(originalFile);
using (FileStream fs = new FileStream(watermarkedFile, FileMode.Create, FileAccess.Write, FileShare.None))
// Creating iTextSharp.text.pdf.PdfStamper object to write Data from iTextSharp.text.pdf.PdfReader object to FileStream object
using (PdfStamper stamper = new PdfStamper(reader1, fs))
{
    // Getting total number of pages of the Existing Document
    int pageCount = reader1.NumberOfPages;

    // Create New Layer for Watermark
    PdfLayer layer = new PdfLayer("WatermarkLayer", stamper.Writer);
    // Loop through each Page
    for (int i = 1; i <= pageCount; i++)
    {
        // Getting the Page Size
        Rectangle rect = reader1.GetPageSize(i);

        // Get the ContentByte object
        PdfContentByte cb = stamper.GetUnderContent(i);

        // Tell the cb that the next commands should be "bound" to this new layer
        cb.BeginLayer(layer);
        cb.SetFontAndSize(BaseFont.CreateFont(
          BaseFont.HELVETICA, BaseFont.CP1252, BaseFont.NOT_EMBEDDED), 50);

        PdfGState gState = new PdfGState();
        gState.FillOpacity = 0.25f;
        cb.SetGState(gState);

        cb.SetColorFill(BaseColor.BLACK);
        cb.BeginText();
        cb.ShowTextAligned(PdfContentByte.ALIGN_CENTER, watermarkText, rect.Width / 2, rect.Height / 2, 45f);
        cb.EndText();

        // Close the layer
        cb.EndLayer();
    }
}

實現結果以下:

使用Removing Layer移除剛剛建立Layer水印的PDF文檔:

Whenever we add Layer in PDF Document, then the content of the Layer resides under OCG Group. So if I remove this Layer we can remove the content of the Layer also e.g. here it is Watermark Text. To remove all the Layers from PDF Document, you have to remove OCG Group completely from the Document usingreader.Catalog.Remove(PdfName.OCPROPERTIES). Now follow the Steps below to remove the Watermark Text from Layer:

Read the existing watermarked document using iTextSharp.text.pdf.PdfReader's object
Taking each Page in the iTextSharp.text.pdf.PdfDictionary's object using GetPageN(int pageNumber) method of iTextSharp.text.pdf.PdfReader's object.
Taking the Content of the Page in the iTextSharp.text.pdf.PdfArray's object usingGetAsArray(PdfName.CONTENTS) method of iTextSharp.text.pdf.PdfDictionary's object
Loop through this array and Get each element as iTextSharp.text.pdf.PRStream's object usingGetAsStream(int arrayIndex) method of iTextSharp.text.pdf.PdfArray's object
Convert each stream into Bytes using Static method GetStreamBytes(PRStream stream) ofiTextSharp.text.pdf.PdfReader class
Convert these Bytes into String using System.Text.Encoding.ASCII.GetString(byte[] bytes)method
Search for the String "/OC" and also the Watermarked Text. If found then remove it by giving it zero length and zero data using two methods: Put() & SetData() of iTextSharp.text.pdf.PRStream class
Write this modified document exists in the reader to a new document usingiTextSharp.text.pdf.PdfStamper's object

Lets Implement it:

// Removing the layer created above
// 1. First we bind a reader to the watermarked file
// 2. Then strip out a branch of things
// 3. Finally use a simple stamper to write out the edited reader
PdfReader reader2 = new PdfReader(watermarkedFile);

// NOTE: This will destroy all layers in the Document, only use if you don't have any addtional layers
// Remove the OCG group completely from the Document: reader2.Catalog.Remove(PdfName.OCPROPERTIES);

// Clean up the reader, optional
reader2.RemoveUnusedObjects();

// Placeholder variables
PRStream stream;
string content;
PdfDictionary page;
PdfArray contentArray;

// Get the number of pages
int pageCount2 = reader2.NumberOfPages;

// Loop through each page
for (int i = 1; i <= pageCount2; i++)
{
    // Get the page
    page = reader2.GetPageN(i);

    // Get the raw content
    contentArray = page.GetAsArray(PdfName.CONTENTS);

    if (contentArray != null)
    {
        // Loop through content
        for (int j = 0; j < contentArray.Size; j++)
        {
            stream = (PRStream)contentArray.GetAsStream(j);

            // Convert to a String, NOTE: you might need a different encoding here
            content = System.Text.Encoding.ASCII.GetString(PdfReader.GetStreamBytes(stream));

            //Look for the OCG token in the stream as well as our watermarked text
            if (content.IndexOf("/OC") >= 0 && content.IndexOf(watermarkText) >= 0)
            {
                //Remove it by giving it zero length and zero data
                stream.Put(PdfName.LENGTH, new PdfNumber(0));
                stream.SetData(new byte[0]);
            }
        }
    }
}

// Write the content out
using (FileStream fs = new FileStream(unwatermarkedFile, 
          FileMode.Create, FileAccess.Write, FileShare.None))
using (PdfStamper stamper = new PdfStamper(reader2, fs)) { }

在建立過程爲每一頁添加水印:

Now, we already know that, watermark cannot be add during Page creation, it have to add after document creation. So, I've created a class PDFWriterEvents which implements the interface iTextSharp.text.pdf.IPdfPageEventand modify the event OnStartPage. This interface contains a set of events from the Openning & to Closing the PDF Document. The events are following:

public void OnOpenDocument(PdfWriter writer, Document document)
public void OnCloseDocument(PdfWriter writer, Document document)
public void OnStartPage(PdfWriter writer, Document document)
public void OnEndPage(PdfWriter writer, Document document)
public void OnParagraph(PdfWriter writer, Document document, float paragraphPosition)
public void OnParagraphEnd(PdfWriter writer, Document document, float paragraphPosition)
public void OnChapter(PdfWriter writer, Document document, float paragraphPosition, Paragraph title)
public void OnChapterEnd(PdfWriter writer, Document document, float paragraphPosition)
public void OnSection(PdfWriter writer, Document document, float paragraphPosition, int depth, Paragraph title)
public void OnSectionEnd(PdfWriter writer, Document document, float paragraphPosition)
public void OnGenericTag(PdfWriter writer, Document document, Rectangle rect, String text)

You may modify other events accroding to your needs which occured against a particular action. Let see the which I've created:

// Creating Watermark inside OnStartPage Event by implementing IPdfPageEvent interface
// So that, dusring Page Creation, Watermark will be create
class PDFWriterEvents : IPdfPageEvent
{
    string watermarkText;
    float fontSize = 80f;
    float xPosition = 300f;
    float yPosition = 800f;
    float angle = 45f;

    public PDFWriterEvents(string watermarkText, float fontSize = 80f, 
       float xPosition = 300f, float yPosition = 400f, float angle = 45f)
    {
        this.watermarkText = watermarkText;
        this.xPosition = xPosition;
        this.yPosition = yPosition;
        this.angle = angle;
    }

    public void OnOpenDocument(PdfWriter writer, Document document) { }
    public void OnCloseDocument(PdfWriter writer, Document document) { }
    public void OnStartPage(PdfWriter writer, Document document)
    {
        try
        {
            PdfContentByte cb = writer.DirectContentUnder;
            BaseFont baseFont = BaseFont.CreateFont(BaseFont.HELVETICA, BaseFont.WINANSI, BaseFont.EMBEDDED);
            cb.BeginText();
            cb.SetColorFill(BaseColor.LIGHT_GRAY);
            cb.SetFontAndSize(baseFont, fontSize);
            cb.ShowTextAligned(PdfContentByte.ALIGN_CENTER, watermarkText, xPosition, yPosition, angle);
            cb.EndText();
        }
        catch (DocumentException docEx)
        {
            throw docEx;
        }
    }
    public void OnEndPage(PdfWriter writer, Document document) { }
    public void OnParagraph(PdfWriter writer, Document document, float paragraphPosition) { }
    public void OnParagraphEnd(PdfWriter writer, Document document, float paragraphPosition) { }
    public void OnChapter(PdfWriter writer, Document document, float paragraphPosition, Paragraph title) { }
    public void OnChapterEnd(PdfWriter writer, Document document, float paragraphPosition) { }
    public void OnSection(PdfWriter writer, Document document, float paragraphPosition, int depth, Paragraph title) { }
    public void OnSectionEnd(PdfWriter writer, Document document, float paragraphPosition) { }
    public void OnGenericTag(PdfWriter writer, Document document, Rectangle rect, String text) { }
}

Lets see how & when you use the object of this class:

using (FileStream fs = new FileStream(
      "Watermark_During_Page_Creation.pdf", FileMode.Create, FileAccess.Write, FileShare.None))
using (Document doc = new Document(PageSize.LETTER))
using (PdfWriter writer = PdfWriter.GetInstance(doc, fs))
{
    writer.PageEvent = new PDFWriterEvents("This is a Test");
    doc.Open();
    doc.Add(new Paragraph("This is a page 1"));
    doc.Close();
}

See, OnStartPage event called during adding a new paragraph. So I don't need to add watermark later

在不存盤的狀況下，導出/打印/輸出PDF文件到客戶端:

We can create PDF File in memory by creatig System.IO.MemorySystem's object. Lets see:

using (MemoryStream ms = new MemoryStream())
using(Document document = new Document(PageSize.A4, 25, 25, 30, 30))
using(PdfWriter writer = PdfWriter.GetInstance(document, ms))
{
    document.Open();
    document.Add(new Paragraph("Hello World"));
    document.Close();
    writer.Close();
    ms.Close();
    Response.ContentType = "pdf/application";
    Response.AddHeader("content-disposition", "attachment;filename=First_PDF_document.pdf");
    Response.OutputStream.Write(ms.GetBuffer(), 0, ms.GetBuffer().Length);
}

設置PDF瀏覽參數:

The values of the different ViewerPreferences were originally stored in iTextSharp.text.pdf.PdfWriter class as an integer constant. You can set the ViewerPreferences by following two ways:

By setting property ViewerPreferences of iTextSharp.text.pdf.PdfWriter class. To know all theViewerPreferences and its purpose, please read this first. E.g.-
```
writer.ViewerPreferences = PdfWriter.HideMenubar;
```
By calling method AddViewerPreference(PdfName key, PdfObject value) ofiTextSharp.text.pdf.PdfWriter's object. To know which value is appropiate for which key, read thisfirst. E.g.-
```
writer.AddViewerPreference(PdfName.HIDEMENUBAR, new PdfBoolean(true));
```

加密PDF文檔:

By SetEncryption() method of iTextSharp.text.pdf.PdfWriter's object, we can encrypt a PDF document. Read full documentation of this method here. To know all the encryption types, click here. E.g.-

writer.SetEncryption(PdfWriter.STRENGTH40BITS, null, null, PdfWriter.ALLOW_COPY);

聲明

Please download the source code for detail. I hope you'll understand as the source code is documented. If any doubt, just post your comment below. Thank you.