VB.Net Tutorial/Stream File/FileSystem

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Версия от 12:56, 26 мая 2010; Admin (обсуждение | вклад) (1 версия)
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Drive TotalFreeSpace, AvailableFreeSpace and TotalSize

Public Class Tester
    Public Shared Sub Main
        Dim oneDrive As IO.DriveInfo = My.ruputer.FileSystem.GetDriveInfo("C:\\")
        Console.WriteLine(Format(oneDrive.TotalFreeSpace,"#,##0") & " bytes")
        Console.WriteLine(Format(oneDrive.AvailableFreeSpace,"#,##0") & " bytes")
        Console.WriteLine(Format(oneDrive.TotalSize,"#,##0") & " bytes")
    End Sub
End Class
35,532,111,872 bytes
35,532,111,872 bytes
60,003,381,248 bytes

Find in files

Option Strict On
Imports Microsoft.VisualBasic.FileIO
Imports System.Collections.ObjectModel
Public Module FileFind
   Public Sub Main()
      Dim filespec() As String = {"*.vb"}
      Dim matches As ReadOnlyCollection(Of String)
      matches = My.ruputer.FileSystem.FindInFiles(".", "Class", False,SearchOption.SearchTopLevelO
nly, filespec)
      If matches.Count > 0 Then
         Console.WriteLine(""Class" found in:")
         For Each filename As String In matches
            Console.WriteLine(" " & filename)
         Next
      Else
         Console.WriteLine("No matches found.")
      End If
   End Sub
End Module
"Class" found in:
 C:\Java_Dev\WEB\dev\VB\Addaprinterprocess.vb
 C:\Java_Dev\WEB\dev\VB\Addfirstpointandsizetoanotherpoint.vb

List all available Drives

Option Strict On
Imports System.Collections.ObjectModel
Imports System.IO
Public Module IterateDrives
   Public Sub Main()
      Dim drives As ReadOnlyCollection(Of DriveInfo)
      drives = My.ruputer.FileSystem.Drives
      For Each drive As DriveInfo In drives
         Console.WriteLine(drive.Name)
      Next
   End Sub
End Module
C:\
D:\

My.Computer.FileSystem.CurrentDirectory

Public Class Tester
    Public Shared Sub Main
        Dim headings() As String = {"Alpha", "Beta", "Gamma"}
        Dim workText As String = String.Join(",", headings)
        workText &= "1.1, 2.3, 4.5" & vbNewLine
        Dim filePath As String = My.ruputer.FileSystem.CurrentDirectory & "\Test.csv"
        My.ruputer.FileSystem.WriteAllText(filePath, workText, False)

    End Sub
End Class

My.Computer.FileSystem.DirectoryExists

Public Class Tester
    Public Shared Sub Main
        If (My.ruputer.FileSystem.DirectoryExists("C:\\")) Then
            Console.WriteLine("The directory already exists.")
        Else
            Console.WriteLine("The directory does not exist, " & _
               "or is part of an invalid path.")
        End If
    End Sub
End Class
The directory already exists.

My.Computer.FileSystem.FileExists(""FileName"")

Public Class Tester
    Public Shared Sub Main
    
    
        Console.WriteLine(My.ruputer.FileSystem.FileExists("test.txt"))
    End Sub
End Class
True

My.Computer.FileSystem.FindInFiles

Imports System.Collections.ObjectModel
Imports System.IO
public class Test
   public Shared Sub Main
        Dim file_names As ReadOnlyCollection(Of String)
        file_names = My.ruputer.FileSystem.FindInFiles("c:\\", "searchFor.txt",True, _
            FileIO.SearchOption.SearchAllSubDirectories)
        For Each file_name As String In file_names
            Console.WriteLine(file_name)
        Next file_name
   End Sub
End class

My.Computer.FileSystem.GetParentPath

public class Test
   public Shared Sub Main
        Dim start_dir As String = System.Windows.Forms.Application.StartupPath
        start_dir = My.ruputer.FileSystem.GetParentPath(start_dir)
        Console.WriteLine(start_dir)
   End Sub
   
   
End class
C:\Java_Dev\WEB\dev

My.Computer.FileSystem.ReadAllText

Public Class Tester
    Public Shared Sub Main
        Dim csvFile As String = My.Application.Info.DirectoryPath & "\Test.csv"
        Dim outFile As IO.StreamWriter = My.ruputer.FileSystem.OpenTextFileWriter(csvFile, False)

        outFile.WriteLine("Column 1, Column 2, Column 3")
        outFile.WriteLine("1.23, 4.56, 7.89")
        outFile.WriteLine("3.21, 6.54, 9.87")
        outFile.Close()
        Console.WriteLine(My.ruputer.FileSystem.ReadAllText(csvFile))
    End Sub
End Class
Column 1, Column 2, Column 3
1.23, 4.56, 7.89
3.21, 6.54, 9.87

My.Computer.FileSystem.WriteAllText

Public Class Tester
    Public Shared Sub Main
        Dim headings() As String = {"Alpha", "Beta", "Gamma"}
        Dim workText As String = String.Join(",", headings)
        workText &= "1.1, 2.3, 4.5" & vbNewLine
        Dim filePath As String = My.ruputer.FileSystem.CurrentDirectory & "\Test.csv"
        My.ruputer.FileSystem.WriteAllText(filePath, workText, False)

    End Sub
End Class

Test for a valid directory

Public Class Tester
    Public Shared Sub Main
        If (My.ruputer.FileSystem.DirectoryExists("C:\\")) Then
            Console.WriteLine("The directory already exists.")
        Else
            Console.WriteLine("The directory does not exist, " & _
               "or is part of an invalid path.")
        End If
    End Sub
End Class
The directory already exists.

Use pattern(wildcard) to match directories

Imports System.Runtime.Serialization
Public Class Tester
    Public Shared Sub Main
        For Each oneItem As String In My.ruputer.FileSystem.GetDirectories("c:\\",FileIO.SearchOption.SearchTopLevelOnly, "*.txt")
            Console.WriteLine("[" & My.ruputer.FileSystem.GetName(oneItem) & "]")
        Next oneItem
    End Sub
End Class

Use pattern(wildcard) to match files

Imports System.Runtime.Serialization
Public Class Tester
    Public Shared Sub Main
        For Each oneItem As String In My.ruputer.FileSystem.GetFiles("c:\\", _
              FileIO.SearchOption.SearchTopLevelOnly,"*.txt")
            Console.WriteLine(My.ruputer.FileSystem.GetName(oneItem))
        Next oneItem
    End Sub
End Class
DebugMessages.txt
test.txt
test1.txt