Refaktor menggunakan fungsi murni (LINQ ke XML)

Contoh berikut merefaktor contoh sebelumnya, Refaktor menggunakan metode ekstensi, untuk menggunakan fungsi murni. Ini memindahkan kode yang menemukan teks paragraf ke metode ParagraphTextstatik murni.

Contoh: Mengambil node paragraf dan gayanya

Contoh ini memproses dokumen WordprocessingML, mengambil simpul paragraf. Ini juga mengidentifikasi gaya setiap paragraf. Contoh ini dibangun pada contoh sebelumnya dalam tutorial ini. Kode yang direfaktor dipanggil dalam komentar dalam kode di bawah ini.

Instruksi untuk membuat dokumen sumber untuk contoh ini ada di Membuat dokumen Office Open XML sumber.

Contoh ini menggunakan kelas dari rakitan WindowsBase. Ini menggunakan jenis di namespace 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
{
    // This is a new method that assembles the paragraph text.
    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)
            };

        foreach (var p in paraWithText)
            Console.WriteLine("StyleName:{0} >{1}<", p.StyleName, p.Text);
    }
}

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 = New StringBuilder()
        For Each s 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 = 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 = 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 = New StringBuilder()
        For Each item As T In source
            sb.Append(func(item)).Append(separator)
        Next
        Return sb.ToString()
    End Function

    ' This is a new method that assembles the paragraph text.
    Public Function ParagraphText(ByVal e As XElement) As String
        Dim w = 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 styleRelation IsNot 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 = _
            ( _
                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 = 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) _
            }

        For Each p In paraWithText
            Console.WriteLine("StyleName:{0} >{1}<", p.StyleName, p.Text)
        Next
    End Sub
End Module

Contoh ini menghasilkan output yang sama seperti sebelum refaktor:

StyleName:Heading1 >Parsing WordprocessingML with LINQ to XML<
StyleName:Normal ><
StyleName:Normal >The following example prints to the console.<
StyleName:Normal ><
StyleName:Code >using System;<
StyleName:Code ><
StyleName:Code >class Program {<
StyleName:Code >    public static void (string[] args) {<
StyleName:Code >        Console.WriteLine("Hello World");<
StyleName:Code >    }<
StyleName:Code >}<
StyleName:Normal ><
StyleName:Normal >This example produces the following output:<
StyleName:Normal ><
StyleName:Code >Hello World<

StyleName:Heading1 >Parsing WordprocessingML with LINQ to XML<
StyleName:Normal ><
StyleName:Normal >The following example prints to the console.<
StyleName:Normal ><
StyleName:Code >Imports System<
StyleName:Code ><
StyleName:Code >Class Program<
StyleName:Code >    Public Shared  Sub Main(ByVal args() As String)<
StyleName:Code >        Console.WriteLine("Hello World")<
StyleName:Code >   End Sub<
StyleName:Code >End Class<
StyleName:Normal ><
StyleName:Normal >This example produces the following output:<
StyleName:Normal ><
StyleName:Code >Hello World<

Artikel berikutnya dalam tutorial ini menunjukkan cara memproyeksikan XML ke dalam bentuk yang berbeda:

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