VB.Net Tutorial/Stream File/File Utilities

Copy a file

Imports System.IO
Imports System.Text
        
Public Class Tester
    Public Shared Sub Main
    
        Dim mySourceFileStream As FileStream
        Dim myDestFileStream As FileStream
        Dim bteRead() As Byte
        Dim intByte As Integer
        Dim bteMessage(128) As Byte
        Dim strCopyMessage As String = ""
        Try
            myDestFileStream = New FileStream("dest.txt", FileMode.OpenOrCreate, FileAccess.Write)
            bteMessage = Encoding.ASCII.GetBytes(strCopyMessage)
            myDestFileStream.Write(bteMessage, 0, bteMessage.Length)
            mySourceFileStream = New FileStream("source.txt", FileMode.OpenOrCreate, FileAccess.Read)
            intByte = mySourceFileStream.Length
            ReDim bteRead(intByte)
            mySourceFileStream.Read(bteRead, 0, intByte)
            myDestFileStream.Write(bteRead, 0, intByte)
            myDestFileStream.Close()
            mySourceFileStream.Close()
        Catch ex As IOException
            Console.WriteLine(ex.Message)
        End Try
    End Sub
End Class

Delete a file

Imports System.IO
Public Class Tester
    Public Shared Sub Main
        Dim f As File
        f.Delete("test.txt")
    End Sub
End Class

Delete a file with kill

Public Class Tester
    Public Shared Sub Main
        Kill("Test.csv")
    End Sub
End Class

File copy

Imports System.Windows.Forms
public class FileOpenDialogFilter
   public Shared Sub Main
      System.IO.File.Copy("c:\\test.txt", "c:\\test1.txt", True)
   End Sub
End class

Move a File

Public Class Tester
    Declare Auto Function MoveFile Lib "KERNEL32.dll" Alias "MoveFile" (ByVal src As String, ByVal
dst As String) As Boolean
    Public Shared Sub Main
    
    
            MoveFile("d:\\test.txt", "c:\\test.txt")
    End Sub
End Class

Move a file with File.Move

Imports System.IO
Public Class Tester
    Public Shared Sub Main
        Dim f As File
        f.Move("test.txt", "text2.txt")
    End Sub
End Class

Unhandled Exception: System.IO.IOException: Cannot create a file when that file already exists.
   at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
   at System.IO.__Error.WinIOError()
   at System.IO.File.Move(String sourceFileName, String destFileName)
   at Tester.Main()

Use FreeFile

Option Strict On
Public Module Checking
   Private Const filename As String = "CheckFile.dat"
   Public Sub Main()
      Dim fn As Integer = FreeFile
      Dim fileOpened As Boolean
      Try
         FileOpen(fn, filename, OpenMode.Append)
         fileOpened = True
         WriteLine(fn, 1605, Date.Now, "Books", 2.19)
      Catch e As Exception
         Console.WriteLine(e.GetType().Name & ": " & e.Message)
      Finally
         If fileOpened Then FileClose(fn)
      End Try
   End Sub
End Module

Use FreeFile to read a text file

public class Test
   public Shared Sub Main
        Dim file_num As Integer = FreeFile()
        Dim file_name As String = "test.txt"
        FileOpen(file_num, file_name, OpenMode.Input, OpenAccess.Read, OpenShare.Shared)
        Do While Not EOF(file_num)
            Dim txt As String = LineInput(file_num)
            Console.WriteLine(txt)
        Loop
        FileClose(file_num)
   End Sub
End class

Use the HMACSHA1 hashing function to generate a checksum for a file.

Imports System.Text
Imports System.Security.Cryptography
Public Class Tester
    Public Shared Sub Main
        Dim checksum1 As Byte()
        checksum1 = GenerateFileChecksum("test.txt")
    End Sub
    Public Shared Function GenerateFileChecksum(ByVal filePath As String) As Byte()
        Dim hashingFunction As HMACSHA1
        Dim hasingBase() As Byte
        Dim hashValue() As Byte
        Dim inStream As IO.Stream
        If (My.ruputer.FileSystem.FileExists(filePath)= False) Then
            Throw New IO.FileNotFoundException
            Return Nothing
        End If
        hasingBase = (New UnicodeEncoding).GetBytes("Cookbook")
        hashingFunction = New HMACSHA1(hasingBase, True)
        inStream = New IO.FileStream(filePath,IO.FileMode.Open, IO.FileAccess.Read)
        hashValue = hashingFunction.ruputeHash(inStream)
        inStream.Close()
        Return hashValue
    End Function
End Class