XML do projeto em uma forma diferente (LINQ to XML)

Este artigo mostra um exemplo de projeção de XML em uma forma que difere do XML de origem.

Muitas transformações XML típicas consistem em consultas encadeadas, como neste exemplo. É comum começar com alguma forma de XML, resultados intermediários do projeto como coleções de tipos anônimos ou tipos nomeados e, em seguida, projetar os resultados de volta em XML de uma forma totalmente diferente do XML de origem.

Exemplo: Recuperar nós de parágrafo e identificar o estilo e o texto de cada parágrafo

Este exemplo recupera os nós de parágrafo de um documento WordprocessingML e identifica o estilo e o texto de cada parágrafo. Em seguida, projeta XML de uma forma diferente. O exemplo baseia-se nos exemplos anteriores neste tutorial. A afirmação que foi adicionada para fazer a projeção é apontada por comentários no código.

As instruções para criar o documento de origem para este exemplo estão em Criar o documento Office Open XML de origem.

Este exemplo usa classes do assembly WindowsBase. Ele usa tipos no System.IO.Packaging namespace.

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

A versão C# deste exemplo produz a seguinte saída:

<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>

A versão do Visual Basic deste exemplo produz a seguinte saída:

<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>

O próximo artigo neste tutorial mostra como encontrar todo o texto em um documento do Word:

• Localizar texto em documentos do Word

Consulte também

• Tutorial: Manipular conteúdo em um documento WordprocessingML