VisitParagraphStart
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[
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]DocumentVisitor.VisitParagraphStart method
Called when enumeration of a paragraph has started.
public virtual VisitorAction VisitParagraphStart(Paragraph paragraph)
| Parameter | Type | Description |
|---|---|---|
| paragraph | Paragraph | The object that is being visited. |
Return Value
A VisitorAction value that specifies how to continue the enumeration.
Examples
Shows how to use a document visitor to print a document’s node structure.
public void DocStructureToText()
{
Document doc = new Document(MyDir + "DocumentVisitor-compatible features.docx");
DocStructurePrinter visitor = new DocStructurePrinter();
// When we get a composite node to accept a document visitor, the visitor visits the accepting node,
// and then traverses all the node's children in a depth-first manner.
// The visitor can read and modify each visited node.
doc.Accept(visitor);
Console.WriteLine(visitor.GetText());
}
/// <summary>
/// Traverses a node's tree of child nodes.
/// Creates a map of this tree in the form of a string.
/// </summary>
public class DocStructurePrinter : DocumentVisitor
{
public DocStructurePrinter()
{
mAcceptingNodeChildTree = new StringBuilder();
}
public string GetText()
{
return mAcceptingNodeChildTree.ToString();
}
/// <summary>
/// Called when a Document node is encountered.
/// </summary>
public override VisitorAction VisitDocumentStart(Document doc)
{
int childNodeCount = doc.GetChildNodes(NodeType.Any, true).Count;
IndentAndAppendLine("[Document start] Child nodes: " + childNodeCount);
mDocTraversalDepth++;
// Allow the visitor to continue visiting other nodes.
return VisitorAction.Continue;
}
/// <summary>
/// Called after all the child nodes of a Document node have been visited.
/// </summary>
public override VisitorAction VisitDocumentEnd(Document doc)
{
mDocTraversalDepth--;
IndentAndAppendLine("[Document end]");
return VisitorAction.Continue;
}
/// <summary>
/// Called when a Section node is encountered in the document.
/// </summary>
public override VisitorAction VisitSectionStart(Section section)
{
// Get the index of our section within the document.
NodeCollection docSections = section.Document.GetChildNodes(NodeType.Section, false);
int sectionIndex = docSections.IndexOf(section);
IndentAndAppendLine("[Section start] Section index: " + sectionIndex);
mDocTraversalDepth++;
return VisitorAction.Continue;
}
/// <summary>
/// Called after all the child nodes of a Section node have been visited.
/// </summary>
public override VisitorAction VisitSectionEnd(Section section)
{
mDocTraversalDepth--;
IndentAndAppendLine("[Section end]");
return VisitorAction.Continue;
}
/// <summary>
/// Called when a Body node is encountered in the document.
/// </summary>
public override VisitorAction VisitBodyStart(Body body)
{
int paragraphCount = body.Paragraphs.Count;
IndentAndAppendLine("[Body start] Paragraphs: " + paragraphCount);
mDocTraversalDepth++;
return VisitorAction.Continue;
}
/// <summary>
/// Called after all the child nodes of a Body node have been visited.
/// </summary>
public override VisitorAction VisitBodyEnd(Body body)
{
mDocTraversalDepth--;
IndentAndAppendLine("[Body end]");
return VisitorAction.Continue;
}
/// <summary>
/// Called when a Paragraph node is encountered in the document.
/// </summary>
public override VisitorAction VisitParagraphStart(Paragraph paragraph)
{
IndentAndAppendLine("[Paragraph start]");
mDocTraversalDepth++;
return VisitorAction.Continue;
}
/// <summary>
/// Called after all the child nodes of a Paragraph node have been visited.
/// </summary>
public override VisitorAction VisitParagraphEnd(Paragraph paragraph)
{
mDocTraversalDepth--;
IndentAndAppendLine("[Paragraph end]");
return VisitorAction.Continue;
}
/// <summary>
/// Called when a Run node is encountered in the document.
/// </summary>
public override VisitorAction VisitRun(Run run)
{
IndentAndAppendLine("[Run] \"" + run.GetText() + "\"");
return VisitorAction.Continue;
}
/// <summary>
/// Called when a SubDocument node is encountered in the document.
/// </summary>
public override VisitorAction VisitSubDocument(SubDocument subDocument)
{
IndentAndAppendLine("[SubDocument]");
return VisitorAction.Continue;
}
/// <summary>
/// Called when a SubDocument node is encountered in the document.
/// </summary>
public override VisitorAction VisitStructuredDocumentTagRangeStart(StructuredDocumentTagRangeStart sdtRangeStart)
{
IndentAndAppendLine("[SdtRangeStart]");
return VisitorAction.Continue;
}
/// <summary>
/// Called when a SubDocument node is encountered in the document.
/// </summary>
public override VisitorAction VisitStructuredDocumentTagRangeEnd(StructuredDocumentTagRangeEnd sdtRangeEnd)
{
IndentAndAppendLine("[SdtRangeEnd]");
return VisitorAction.Continue;
}
/// <summary>
/// Append a line to the StringBuilder and indent it depending on how deep the visitor is into the document tree.
/// </summary>
/// <param name="text"></param>
private void IndentAndAppendLine(string text)
{
for (int i = 0; i < mDocTraversalDepth; i++) mAcceptingNodeChildTree.Append("| ");
mAcceptingNodeChildTree.AppendLine(text);
}
private int mDocTraversalDepth;
private readonly StringBuilder mAcceptingNodeChildTree;
}
Shows how to use a DocumentVisitor implementation to remove all hidden content from a document.
public void RemoveHiddenContentFromDocument()
{
Document doc = new Document(MyDir + "Hidden content.docx");
RemoveHiddenContentVisitor hiddenContentRemover = new RemoveHiddenContentVisitor();
// Below are three types of fields which can accept a document visitor,
// which will allow it to visit the accepting node, and then traverse its child nodes in a depth-first manner.
// 1 - Paragraph node:
Paragraph para = (Paragraph)doc.GetChild(NodeType.Paragraph, 4, true);
para.Accept(hiddenContentRemover);
// 2 - Table node:
Table table = doc.FirstSection.Body.Tables[0];
table.Accept(hiddenContentRemover);
// 3 - Document node:
doc.Accept(hiddenContentRemover);
doc.Save(ArtifactsDir + "Font.RemoveHiddenContentFromDocument.docx");
}
/// <summary>
/// Removes all visited nodes marked as "hidden content".
/// </summary>
public class RemoveHiddenContentVisitor : DocumentVisitor
{
/// <summary>
/// Called when a FieldStart node is encountered in the document.
/// </summary>
public override VisitorAction VisitFieldStart(FieldStart fieldStart)
{
if (fieldStart.Font.Hidden)
fieldStart.Remove();
return VisitorAction.Continue;
}
/// <summary>
/// Called when a FieldEnd node is encountered in the document.
/// </summary>
public override VisitorAction VisitFieldEnd(FieldEnd fieldEnd)
{
if (fieldEnd.Font.Hidden)
fieldEnd.Remove();
return VisitorAction.Continue;
}
/// <summary>
/// Called when a FieldSeparator node is encountered in the document.
/// </summary>
public override VisitorAction VisitFieldSeparator(FieldSeparator fieldSeparator)
{
if (fieldSeparator.Font.Hidden)
fieldSeparator.Remove();
return VisitorAction.Continue;
}
/// <summary>
/// Called when a Run node is encountered in the document.
/// </summary>
public override VisitorAction VisitRun(Run run)
{
if (run.Font.Hidden)
run.Remove();
return VisitorAction.Continue;
}
/// <summary>
/// Called when a Paragraph node is encountered in the document.
/// </summary>
public override VisitorAction VisitParagraphStart(Paragraph paragraph)
{
if (paragraph.ParagraphBreakFont.Hidden)
paragraph.Remove();
return VisitorAction.Continue;
}
/// <summary>
/// Called when a FormField is encountered in the document.
/// </summary>
public override VisitorAction VisitFormField(FormField formField)
{
if (formField.Font.Hidden)
formField.Remove();
return VisitorAction.Continue;
}
/// <summary>
/// Called when a GroupShape is encountered in the document.
/// </summary>
public override VisitorAction VisitGroupShapeStart(GroupShape groupShape)
{
if (groupShape.Font.Hidden)
groupShape.Remove();
return VisitorAction.Continue;
}
/// <summary>
/// Called when a Shape is encountered in the document.
/// </summary>
public override VisitorAction VisitShapeStart(Shape shape)
{
if (shape.Font.Hidden)
shape.Remove();
return VisitorAction.Continue;
}
/// <summary>
/// Called when a Comment is encountered in the document.
/// </summary>
public override VisitorAction VisitCommentStart(Comment comment)
{
if (comment.Font.Hidden)
comment.Remove();
return VisitorAction.Continue;
}
/// <summary>
/// Called when a Footnote is encountered in the document.
/// </summary>
public override VisitorAction VisitFootnoteStart(Footnote footnote)
{
if (footnote.Font.Hidden)
footnote.Remove();
return VisitorAction.Continue;
}
/// <summary>
/// Called when a SpecialCharacter is encountered in the document.
/// </summary>
public override VisitorAction VisitSpecialChar(SpecialChar specialChar)
{
Console.WriteLine(specialChar.GetText());
if (specialChar.Font.Hidden)
specialChar.Remove();
return VisitorAction.Continue;
}
/// <summary>
/// Called when visiting of a Table node is ended in the document.
/// </summary>
public override VisitorAction VisitTableEnd(Table table)
{
// The content inside table cells may have the hidden content flag, but the tables themselves cannot.
// If this table had nothing but hidden content, this visitor would have removed all of it,
// and there would be no child nodes left.
// Thus, we can also treat the table itself as hidden content and remove it.
// Tables which are empty but do not have hidden content will have cells with empty paragraphs inside,
// which this visitor will not remove.
if (!table.HasChildNodes)
table.Remove();
return VisitorAction.Continue;
}
/// <summary>
/// Called when visiting of a Cell node is ended in the document.
/// </summary>
public override VisitorAction VisitCellEnd(Cell cell)
{
if (!cell.HasChildNodes && cell.ParentNode != null)
cell.Remove();
return VisitorAction.Continue;
}
/// <summary>
/// Called when visiting of a Row node is ended in the document.
/// </summary>
public override VisitorAction VisitRowEnd(Row row)
{
if (!row.HasChildNodes && row.ParentNode != null)
row.Remove();
return VisitorAction.Continue;
}
}
See Also
- enum VisitorAction
- class Paragraph
- class DocumentVisitor
- namespace Aspose.Words
- assembly Aspose.Words
