This example demonstrates how to use a DocumentIterator object and a DocumentVisitor implementation to export a document in a custom format. The DocumentIterator
navigates through document elements. The document visitor is used to export document elements to a lightweight markup language (Markdown).
Implementation
The document visitor is implemented according to the Visitor pattern. In this example, the custom document visitor is inherited from the DocumentVisitorBase class. The DocumentVisitorBase class implements the IDocumentVisitor interface. This means you can override only the methods of the DocumentVisitorBase class to process documents.
The document iterator moves over each document structure item and passes a custom document visitor object to the current item. The custom document visitor builds a string with lightweight markup for the processed document item.
Files to Review
- Program.cs (VB: Program.vb)
- MarkdownVisitor (VB: MarkdownVisitor.vb)
Documentation
Does this example address your development requirements/objectives?
(you will be redirected to DevExpress.com to submit your response)
Example Code
C#using DevExpress.XtraRichEdit;
using DevExpress.XtraRichEdit.API.Native;
using System;
using System.Diagnostics;
using System.IO;
namespace DocumentIteratorExample {
class Program {
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main(string[] args) {
using (RichEditDocumentServer wordProcessor = new RichEditDocumentServer())
{
wordProcessor.LoadDocument("Markdown.docx", DocumentFormat.OpenXml);
Document document = wordProcessor.Document;
MarkdownVisitor visitor = new MarkdownVisitor();
Iterate(visitor, document);
string newFilePath = "output.md";
File.WriteAllText(newFilePath, visitor.Text);
}
var p = new Process();
p.StartInfo = new ProcessStartInfo(@"output.md")
{
UseShellExecute = true
};
p.Start();
}
private static void Iterate(IDocumentVisitor visitor, Document document)
{
DocumentIterator iterator = new DocumentIterator(document, true);
while (iterator.MoveNext())
iterator.Current.Accept(visitor);
}
}
}
C#using DevExpress.XtraRichEdit.API.Native;
using System;
using System.Linq;
using System.Text;
namespace DocumentIteratorExample
{
public abstract class BufferedDocumentVisitor : DocumentVisitorBase
{
readonly StringBuilder buffer;
protected BufferedDocumentVisitor()
{
this.buffer = new StringBuilder();
}
protected StringBuilder Buffer { get { return buffer; } }
}
public class MarkdownVisitor : BufferedDocumentVisitor
{
const char lastLowSpecial = '\x1f';
const char firstHighSpecial = '\xffff';
public string Text { get { return Buffer.ToString(); } }
public override void Visit(DocumentText text)
{
string prefix = GetPrefix(text.TextProperties);
Buffer.Append(prefix);
int count = text.Length;
for (int i = 0; i < count; i++)
{
char ch = text.Text[i];
if (ch > lastLowSpecial && ch < firstHighSpecial)
Buffer.Append(ch);
else if (ch == '\x9' || ch == '\xA' || ch == '\xD')
Buffer.Append(ch);
}
Buffer.Append(prefix);
}
public override void Visit(DocumentParagraphStart paragraphStart)
{
if (paragraphStart.ParagraphProperties.ParagraphStyle.Name == "heading 1")
Buffer.Append("#");
}
public override void Visit(DocumentInlinePicture inlinePicture)
{
InsertImageUri(inlinePicture.Uri);
}
public override void Visit(DocumentPicture picture)
{
InsertImageUri(picture.Uri);
}
public override void Visit(DocumentParagraphEnd paragraphEnd)
{
AppendLineOnNonEmptyContent();
}
public override void Visit(DocumentSectionEnd sectionEnd)
{
AppendLineOnNonEmptyContent();
}
public override void Visit(DocumentHyperlinkStart hyperlinkStart)
{
if (!String.IsNullOrEmpty(hyperlinkStart.NavigateUri))
Buffer.Append("[");
}
public override void Visit(DocumentHyperlinkEnd hyperlinkEnd)
{
if (!String.IsNullOrEmpty(hyperlinkEnd.NavigateUri))
Buffer.Append(String.Format("]({0})", hyperlinkEnd.NavigateUri));
}
void InsertImageUri(string uri)
{
if (!string.IsNullOrEmpty(uri))
Buffer.Append(String.Format("", uri));
else
Buffer.Append("[[img src=attached-image.jpg alt=foobar]]");
}
string GetPrefix(ReadOnlyTextProperties properties)
{
string prefix = string.Empty;
if (properties.FontBold)
prefix = "**";
if (properties.FontItalic)
prefix += "*";
if (properties.StrikeoutType == StrikeoutType.Single)
prefix += "~~";
return prefix;
}
void AppendLineOnNonEmptyContent()
{
if (Buffer.Length > 0)
Buffer.AppendLine();
}
}
}