Bagikan melalui

Cara mengkueri konten file dalam folder (LINQ) (Visual Basic)

Contoh ini memperlihatkan cara mengkueri semua file dalam pohon direktori tertentu, membuka setiap file, dan memeriksa kontennya. Jenis teknik ini dapat digunakan untuk membuat indeks atau indeks terbalik konten pohon direktori. Pencarian string sederhana dilakukan dalam contoh ini. Namun, jenis pencocokan pola yang lebih kompleks dapat dilakukan dengan ekspresi reguler. Untuk informasi selengkapnya, lihat Cara: Menggabungkan Kueri LINQ dengan Ekspresi Reguler (Visual Basic).

Contoh

Imports System.IO

Module Module1
    'QueryContents
    Public Sub Main()

        ' Modify this path as necessary.
        Dim startFolder = "C:\Program Files (x86)\Microsoft Visual Studio 14.0"

        ' Take a snapshot of the folder contents.
        Dim dir As New DirectoryInfo(startFolder)
        Dim fileList = dir.GetFiles("*.*", SearchOption.AllDirectories)

        Dim searchTerm = "Welcome"

        ' Search the contents of each file.
        ' A regular expression created with the Regex class
        ' could be used instead of the Contains method.
        Dim queryMatchingFiles = From file In fileList _
                                 Where file.Extension = ".html" _
                                 Let fileText = GetFileText(file.FullName) _
                                 Where fileText.Contains(searchTerm) _
                                 Select file.FullName

        Console.WriteLine("The term " & searchTerm & " was found in:")

        ' Execute the query.
        For Each filename In queryMatchingFiles
            Console.WriteLine(filename)
        Next

        ' Keep the console window open in debug mode.
        Console.WriteLine("Press any key to exit")
        Console.ReadKey()

    End Sub

    ' Read the contents of the file. This is done in a separate
    ' function in order to handle potential file system errors.
    Function GetFileText(name As String) As String

        ' If the file has been deleted, the right thing
        ' to do in this case is return an empty string.
        Dim fileContents = String.Empty

        ' If the file has been deleted since we took
        ' the snapshot, ignore it and return the empty string.
        If File.Exists(name) Then
            fileContents = File.ReadAllText(name)
        End If

        Return fileContents

    End Function
End Module

Mengkompilasi kode

Buat proyek aplikasi konsol Visual Basic, salin dan tempel sampel kode, dan sesuaikan nilai objek Startup di properti proyek.

Lihat juga

  • Last updated on