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Questo articolo illustra un esempio di proiezione di XML in una forma diversa dal codice XML di origine.
Molte trasformazioni XML tipiche sono costituite da query concatenate, come nel caso di questo esempio. Non è infrequente iniziare con un qualche tipo di codice XML, proiettare i risultati intermedi come raccolte di tipi anonimi o con nome e quindi proiettare i risultati nuovamente nel codice XML in una forma completamente diversa rispetto al codice XML di origine.
Esempio: Recuperare i nodi di paragrafi e identificare lo stile e il testo di ogni paragrafo
Questo esempio recupera i nodi di paragrafi da un documento WordprocessingML e identifica lo stile e il testo di ogni paragrafo. Proietta quindi il codice XML di una forma diversa. L'esempio si basa sugli esempi precedenti di questa esercitazione. L'istruzione aggiunta per eseguire la proiezione viene evidenziata dai commenti nel codice.
Per istruzioni per la creazione del documento di origine di questo esempio, vedere Creare il documento Office Open XML di origine.
In questo esempio vengono usate classi dell'assembly WindowsBase e i tipi dello spazio dei nomi System.IO.Packaging.
public static class LocalExtensions
{
public static string StringConcatenate(this IEnumerable<string> source)
{
StringBuilder sb = new StringBuilder();
foreach (string s in source)
sb.Append(s);
return sb.ToString();
}
public static string StringConcatenate<T>(this IEnumerable<T> source,
Func<T, string> func)
{
StringBuilder sb = new StringBuilder();
foreach (T item in source)
sb.Append(func(item));
return sb.ToString();
}
public static string StringConcatenate(this IEnumerable<string> source, string separator)
{
StringBuilder sb = new StringBuilder();
foreach (string s in source)
sb.Append(s).Append(separator);
return sb.ToString();
}
public static string StringConcatenate<T>(this IEnumerable<T> source,
Func<T, string> func, string separator)
{
StringBuilder sb = new StringBuilder();
foreach (T item in source)
sb.Append(func(item)).Append(separator);
return sb.ToString();
}
}
class Program
{
public static string ParagraphText(XElement e)
{
XNamespace w = e.Name.Namespace;
return e
.Elements(w + "r")
.Elements(w + "t")
.StringConcatenate(element => (string)element);
}
static void Main(string[] args)
{
const string fileName = "SampleDoc.docx";
const string documentRelationshipType =
"http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument";
const string stylesRelationshipType =
"http://schemas.openxmlformats.org/officeDocument/2006/relationships/styles";
const string wordmlNamespace =
"http://schemas.openxmlformats.org/wordprocessingml/2006/main";
XNamespace w = wordmlNamespace;
XDocument xDoc = null;
XDocument styleDoc = null;
using (Package wdPackage = Package.Open(fileName, FileMode.Open, FileAccess.Read))
{
PackageRelationship docPackageRelationship =
wdPackage.GetRelationshipsByType(documentRelationshipType).FirstOrDefault();
if (docPackageRelationship != null)
{
Uri documentUri = PackUriHelper.ResolvePartUri(new Uri("/", UriKind.Relative),
docPackageRelationship.TargetUri);
PackagePart documentPart = wdPackage.GetPart(documentUri);
// Load the document XML in the part into an XDocument instance.
xDoc = XDocument.Load(XmlReader.Create(documentPart.GetStream()));
// Find the styles part. There will only be one.
PackageRelationship styleRelation =
documentPart.GetRelationshipsByType(stylesRelationshipType).FirstOrDefault();
if (styleRelation != null)
{
Uri styleUri =
PackUriHelper.ResolvePartUri(documentUri, styleRelation.TargetUri);
PackagePart stylePart = wdPackage.GetPart(styleUri);
// Load the style XML in the part into an XDocument instance.
styleDoc = XDocument.Load(XmlReader.Create(stylePart.GetStream()));
}
}
}
string defaultStyle =
(string)(
from style in styleDoc.Root.Elements(w + "style")
where (string)style.Attribute(w + "type") == "paragraph" &&
(string)style.Attribute(w + "default") == "1"
select style
).First().Attribute(w + "styleId");
// Find all paragraphs in the document.
var paragraphs =
from para in xDoc
.Root
.Element(w + "body")
.Descendants(w + "p")
let styleNode = para
.Elements(w + "pPr")
.Elements(w + "pStyle")
.FirstOrDefault()
select new
{
ParagraphNode = para,
StyleName = styleNode != null ?
(string)styleNode.Attribute(w + "val") :
defaultStyle
};
// Retrieve the text of each paragraph.
var paraWithText =
from para in paragraphs
select new
{
ParagraphNode = para.ParagraphNode,
StyleName = para.StyleName,
Text = ParagraphText(para.ParagraphNode)
};
// The following is the new code that projects XML in a new shape.
XElement root = new XElement("Root",
from p in paraWithText
select new XElement("Paragraph",
new XElement("StyleName", p.StyleName),
new XElement("Text", p.Text)
)
);
Console.WriteLine(root);
}
}
Imports <xmlns:w="http://schemas.openxmlformats.org/wordprocessingml/2006/main">
Module Module1
<System.Runtime.CompilerServices.Extension()> _
Public Function StringConcatenate(ByVal source As IEnumerable(Of String)) As String
Dim sb As StringBuilder = New StringBuilder()
For Each s As String In source
sb.Append(s)
Next
Return sb.ToString()
End Function
<System.Runtime.CompilerServices.Extension()> _
Public Function StringConcatenate(Of T)(ByVal source As IEnumerable(Of T), _
ByVal func As Func(Of T, String)) As String
Dim sb As StringBuilder = New StringBuilder()
For Each item As T In source
sb.Append(func(item))
Next
Return sb.ToString()
End Function
<System.Runtime.CompilerServices.Extension()> _
Public Function StringConcatenate(Of T)(ByVal source As IEnumerable(Of T), _
ByVal separator As String) As String
Dim sb As StringBuilder = New StringBuilder()
For Each s As T In source
sb.Append(s).Append(separator)
Next
Return sb.ToString()
End Function
<System.Runtime.CompilerServices.Extension()> _
Public Function StringConcatenate(Of T)(ByVal source As IEnumerable(Of T), _
ByVal func As Func(Of T, String), ByVal separator As String) As String
Dim sb As StringBuilder = New StringBuilder()
For Each item As T In source
sb.Append(func(item)).Append(separator)
Next
Return sb.ToString()
End Function
Public Function ParagraphText(ByVal e As XElement) As String
Dim w As XNamespace = e.Name.Namespace
Return (e.<w:r>.<w:t>).StringConcatenate(Function(element) CStr(element))
End Function
' Following function is required because Visual Basic doesn't support short circuit evaluation
Private Function GetStyleOfParagraph(ByVal styleNode As XElement, _
ByVal defaultStyle As String) As String
If (styleNode Is Nothing) Then
Return defaultStyle
Else
Return styleNode.@w:val
End If
End Function
Sub Main()
Dim fileName = "SampleDoc.docx"
Dim documentRelationshipType = _
"http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument"
Dim stylesRelationshipType = _
"http://schemas.openxmlformats.org/officeDocument/2006/relationships/styles"
Dim wordmlNamespace = _
"http://schemas.openxmlformats.org/wordprocessingml/2006/main"
Dim xDoc As XDocument = Nothing
Dim styleDoc As XDocument = Nothing
Using wdPackage As Package = Package.Open(fileName, FileMode.Open, FileAccess.Read)
Dim docPackageRelationship As PackageRelationship = _
wdPackage.GetRelationshipsByType(documentRelationshipType).FirstOrDefault()
If (docPackageRelationship IsNot Nothing) Then
Dim documentUri As Uri = PackUriHelper.ResolvePartUri(New Uri("/", UriKind.Relative), _
docPackageRelationship.TargetUri)
Dim documentPart As PackagePart = wdPackage.GetPart(documentUri)
' Load the document XML in the part into an XDocument instance.
xDoc = XDocument.Load(XmlReader.Create(documentPart.GetStream()))
' Find the styles part. There will only be one.
Dim styleRelation As PackageRelationship = _
documentPart.GetRelationshipsByType(stylesRelationshipType).FirstOrDefault()
If (Not (styleRelation Is Nothing)) Then
Dim styleUri As Uri = _
PackUriHelper.ResolvePartUri(documentUri, styleRelation.TargetUri)
Dim stylePart As PackagePart = wdPackage.GetPart(styleUri)
' Load the style XML in the part into an XDocument instance.
styleDoc = XDocument.Load(XmlReader.Create(stylePart.GetStream()))
End If
End If
End Using
Dim defaultStyle As String = _
( _
From style In styleDoc.Root.<w:style> _
Where style.@w:type = "paragraph" And _
style.@w:default = "1" _
Select style _
).First().@w:styleId
' Find all paragraphs in the document.
Dim paragraphs = _
From para In xDoc.Root.<w:body>...<w:p> _
Let styleNode As XElement = para.<w:pPr>.<w:pStyle>.FirstOrDefault _
Select New With { _
.ParagraphNode = para, _
.StyleName = GetStyleOfParagraph(styleNode, defaultStyle) _
}
' Retrieve the text of each paragraph.
Dim paraWithText = _
From para In paragraphs _
Select New With { _
.ParagraphNode = para.ParagraphNode, _
.StyleName = para.StyleName, _
.Text = ParagraphText(para.ParagraphNode) _
}
' Following is the new code that projects XML in a new shape
Dim root As XElement = _
<Root>
<%= _
From p In paraWithText _
Select _
<Paragraph>
<StyleName><%= p.StyleName %></StyleName>
<Text><%= p.Text %></Text>
</Paragraph> _
%>
</Root>
Console.WriteLine(root)
End Sub
End Module
La versione in C# di questo esempio produce l'output seguente:
<Root>
<Paragraph>
<StyleName>Heading1</StyleName>
<Text>Parsing WordprocessingML with LINQ to XML</Text>
</Paragraph>
<Paragraph>
<StyleName>Normal</StyleName>
<Text></Text>
</Paragraph>
<Paragraph>
<StyleName>Normal</StyleName>
<Text>The following example prints to the console.</Text>
</Paragraph>
<Paragraph>
<StyleName>Normal</StyleName>
<Text></Text>
</Paragraph>
<Paragraph>
<StyleName>Code</StyleName>
<Text>using System;</Text>
</Paragraph>
<Paragraph>
<StyleName>Code</StyleName>
<Text></Text>
</Paragraph>
<Paragraph>
<StyleName>Code</StyleName>
<Text>class Program {</Text>
</Paragraph>
<Paragraph>
<StyleName>Code</StyleName>
<Text> public static void (string[] args) {</Text>
</Paragraph>
<Paragraph>
<StyleName>Code</StyleName>
<Text> Console.WriteLine("Hello World");</Text>
</Paragraph>
<Paragraph>
<StyleName>Code</StyleName>
<Text> }</Text>
</Paragraph>
<Paragraph>
<StyleName>Code</StyleName>
<Text>}</Text>
</Paragraph>
<Paragraph>
<StyleName>Normal</StyleName>
<Text></Text>
</Paragraph>
<Paragraph>
<StyleName>Normal</StyleName>
<Text>This example produces the following output:</Text>
</Paragraph>
<Paragraph>
<StyleName>Normal</StyleName>
<Text></Text>
</Paragraph>
<Paragraph>
<StyleName>Code</StyleName>
<Text>Hello World</Text>
</Paragraph>
</Root>
La versione in Visual Basic di questo esempio produce l'output seguente:
<Root>
<Paragraph>
<StyleName>Heading1</StyleName>
<Text>Parsing WordprocessingML with LINQ to XML</Text>
</Paragraph>
<Paragraph>
<StyleName>Normal</StyleName>
<Text></Text>
</Paragraph>
<Paragraph>
<StyleName>Normal</StyleName>
<Text>The following example prints to the console.</Text>
</Paragraph>
<Paragraph>
<StyleName>Normal</StyleName>
<Text></Text>
</Paragraph>
<Paragraph>
<StyleName>Code</StyleName>
<Text>Imports System</Text>
</Paragraph>
<Paragraph>
<StyleName>Code</StyleName>
<Text></Text>
</Paragraph>
<Paragraph>
<StyleName>Code</StyleName>
<Text>Class Program</Text>
</Paragraph>
<Paragraph>
<StyleName>Code</StyleName>
<Text> Public Shared Sub Main(ByVal args() As String)</Text>
</Paragraph>
<Paragraph>
<StyleName>Code</StyleName>
<Text> Console.WriteLine("Hello World")</Text>
</Paragraph>
<Paragraph>
<StyleName>Code</StyleName>
<Text> End Sub</Text>
</Paragraph>
<Paragraph>
<StyleName>Code</StyleName>
<Text>End Class</Text>
</Paragraph>
<Paragraph>
<StyleName>Normal</StyleName>
<Text></Text>
</Paragraph>
<Paragraph>
<StyleName>Normal</StyleName>
<Text>This example produces the following output:</Text>
</Paragraph>
<Paragraph>
<StyleName>Normal</StyleName>
<Text></Text>
</Paragraph>
<Paragraph>
<StyleName>Code</StyleName>
<Text>Hello World</Text>
</Paragraph>
</Root>
L'articolo successivo di questa esercitazione illustra come trovare tutto il testo in un documento di Word:
Vedi anche
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