Projizieren von XML in eine andere Form
Aktualisiert: November 2007
In diesem Thema wird anhand eines Beispiels gezeigt, wie Sie XML in eine andere Form als das Quell-XML projizieren können.
Viele typische XML-Transformationen bestehen aus verketteten Abfragen. Dies trifft auch auf dieses Beispiel zu. Üblicherweise wird mit einer bestimmten Form von XML begonnen, die Zwischenergebnisse werden als Auflistungen anonymer Typen oder benannter Typen projiziert und zum Schluss werden die Ergebnisse zurück in XML projiziert, das eine vollkommen andere Form als das Quell-XML besitzt.
Beispiel
Dieses Beispiel verarbeitet ein WordprocessingML-Dokument, indem es die Absatzknoten aus einem WordprocessingML-Dokument abruft. Außerdem identifiziert es die Formatvorlage und den Text der einzelnen Absätze. Schließlich projiziert das Beispiel XML mit einer anderen Form. Das Beispiel baut auf den vorherigen Beispielen dieses Lernprogramms auf. Die neue Anweisung, die die Projektion ausführt, wird im Code unten durch entsprechende Kommentare gekennzeichnet.
Anweisungen zum Erstellen des Quelldokuments für dieses Beispiel finden Sie unter Erstellen des Office Open XML-Quelldokuments.
Dieses Beispiel verwendet Klassen aus der WindowsBase-Assembly. Außerdem werden Typen im System.IO.Packaging-Namespace verwendet.
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 =
"https://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument";
const string stylesRelationshipType =
"https://schemas.openxmlformats.org/officeDocument/2006/relationships/styles";
const string wordmlNamespace =
"https://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="https://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 VB does not 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 = _
"https://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument"
Dim stylesRelationshipType = _
"https://schemas.openxmlformats.org/officeDocument/2006/relationships/styles"
Dim wordmlNamespace = _
"https://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
Dieses Beispiel führt zur folgenden Ausgabe:
<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>
Nächste Schritte
Im nächsten Beispiel erstellen wir eine Abfrage, die sämtlichen Text in einem Word-Dokument ermittelt:
Siehe auch
Konzepte
Lernprogramm: Bearbeiten des Inhalts eines WordprocessingML-Dokuments