VB.Net Tutorial/Stream File/FileStream

Convert String to ASCII byte code array and save

Imports System.Text
Imports System.IO

Public Class Tester
    Public Shared Sub Main
    
        Dim strSource As String
        Dim bteEndode() As Byte
        Dim myFileStream As New FileStream("test.txt", FileMode.OpenOrCreate, FileAccess.ReadWrite)

        strSource = "asdf"
        bteEndode = Encoding.ASCII.GetBytes(strSource)
  
        
        myFileStream.Write(bteEndode, 0, bteEndode.Length)
  
        myFileStream.Close()
    End Sub
End Class

Convert String to Unicode byte code array and save

Imports System.Text
Imports System.IO

Public Class Tester
    Public Shared Sub Main
    
        Dim strSource As String
        Dim bteEndode() As Byte
        Dim myFileStream As New FileStream("test.txt", FileMode.OpenOrCreate, FileAccess.ReadWrite)

        strSource = "asdf"
        bteEndode = Encoding.Unicode.GetBytes(strSource)
  
        
        myFileStream.Write(bteEndode, 0, bteEndode.Length)
  
        myFileStream.Close()
    End Sub
End Class

FileStream.Length

Imports System.IO

Public Class Tester
    Public Shared Sub Main
        Dim fs As System.IO.FileStream
        Dim r As System.IO.BinaryReader
        Dim buffer(100) As Char
        Dim mylength As Long
        fs = New System.IO.FileStream("test.txt", IO.FileMode.OpenOrCreate)
        r = New System.IO.BinaryReader(fs)
        mylength = fs.Length
        If mylength > 100 Then
            mylength = 100
        End If
        r.Read(buffer, 0, mylength)
        Console.WriteLine(buffer)
        r.Close()
        fs.Close()

    End Sub
End Class

Read a file by using SeekOrigin

Imports System.IO
Imports System.Text
        
Public Class Tester
    Public Shared Sub Main
    
        Dim myFileStream As FileStream
        Dim bteWrite() As Byte
        Dim intByte As Integer
        Dim lngLoop As Long
       
        Try
            intByte = Encoding.ASCII.GetBytes("asdf").Length
            ReDim bteWrite(intByte)
            bteWrite = Encoding.ASCII.GetBytes("asdf")
            myFileStream = File.OpenWrite("test.txt")
            Dim myOrigin As SeekOrigin
            Dim lngPosition As Long
    
            lngPosition = 123
            myOrigin = SeekOrigin.Begin
"           myOrigin = SeekOrigin.Current
"           myOrigin = SeekOrigin.End
            myFileStream.Seek(lngPosition, myOrigin)

            For lngLoop = 0 To intByte - 1
                myFileStream.Seek(1, SeekOrigin.Current)
                myFileStream.WriteByte(bteWrite(lngLoop))
            Next
            myFileStream.Close()
        Catch ex As IOException
            Console.WriteLine(ex.Message)
        End Try
    End Sub
End Class

Read byte array and convert it to ASCII string

Imports System.Text
Imports System.IO

Public Class Tester
    Public Shared Sub Main
        Dim myFileStream As New FileStream("test.txt", FileMode.OpenOrCreate, FileAccess.ReadWrite)
        Dim bteRead() As Byte
        Dim strRead As String
        Dim lngRead As Long
        lngRead = myFileStream.Length
        ReDim bteRead(lngRead)
        myFileStream.Read(bteRead, 0, lngRead)
        strRead = Encoding.ASCII.GetString(bteRead)
        
        Console.WriteLine(strRead)
        myFileStream.Close()
    End Sub
End Class

Read byte array and convert it to Unicode string

Imports System.Text
Imports System.IO

Public Class Tester
    Public Shared Sub Main
        Dim myFileStream As New FileStream("test.txt", FileMode.OpenOrCreate, FileAccess.ReadWrite)
        Dim bteRead() As Byte
        Dim strRead As String
        Dim lngRead As Long
        lngRead = myFileStream.Length
        ReDim bteRead(lngRead)
        myFileStream.Read(bteRead, 0, lngRead)
        strRead = Encoding.Unicode.GetString(bteRead)
        
        Console.WriteLine(strRead)
        myFileStream.Close()
    End Sub
End Class

Read byte using FileStream

Imports System.IO
Imports System.Text
        
Public Class Tester
    Public Shared Sub Main
    
        Dim myFileStream As FileStream
        Dim intByte As Integer
        Dim lngLoop As Long = 0
        Dim bteRead() As Byte
        Try
            myFileStream = File.OpenRead("test.txt")
            ReDim bteRead(myFileStream.Length)
            Do While Not intByte = -1
                intByte = myFileStream.ReadByte()
                If intByte <> -1 Then bteRead(lngLoop) = CByte(intByte)
                lngLoop += 1
            Loop
            Console.WriteLine(Encoding.ASCII.GetString(bteRead))
            myFileStream.Close()
        Catch ex As IOException
            Console.WriteLine(ex.Message)
        End Try
    End Sub
End Class

Read into a buffer

Imports System.IO

Public Class Tester
    Public Shared Sub Main
        Dim f As System.IO.FileStream
        Dim mylength As Integer
        Dim i As Integer
        Dim mybuffer(100) As Byte
        f = New System.IO.FileStream("test.txt", IO.FileMode.Open, IO.FileAccess.Read)
        f.Read(mybuffer, 0, 100)
        For i = 0 To 99
            Console.WriteLine(Chr(mybuffer(i)))
        Next
        f.Close()
    End Sub
End Class

Save UTF8Encoding string to text file

Imports System.IO
Imports System.Text
public class Test
   public Shared Sub Main
        Dim file_stream As New FileStream("test.txt", FileMode.Create)
        Dim bytes As Byte() = New UTF8Encoding().GetBytes("Hello world!")
        file_stream.Write(bytes, 0, bytes.Length)
        file_stream.Close()
   End Sub
End class

Use FileStream to write byte array

Imports System.IO

Public Class Tester
    Public Shared Sub Main
        Dim fs As System.IO.FileStream
        Dim buffer As String
        Dim i As Integer
        Dim myarray(100) As Byte
        fs = New System.IO.FileStream("test.txt", IO.FileMode.OpenOrCreate)
        For i = 0 To 99
            myarray(i) = i
        Next
        fs.Seek(0, System.IO.SeekOrigin.End)
        fs.Write(myarray, 0, 100)
        fs.Close()
    End Sub
End Class

Write Bytes using FileStream

Imports System.IO
Imports System.Text
        
Public Class Tester
    Public Shared Sub Main
    
        Dim myFileStream As FileStream
        Dim bteWrite() As Byte
        Dim intByte As Integer
        Dim lngLoop As Long
        Try
            intByte = Encoding.ASCII.GetBytes("asdf").Length
            ReDim bteWrite(intByte)
            bteWrite = Encoding.ASCII.GetBytes("asdf")
            myFileStream = File.OpenWrite("test.txt")
            
            For lngLoop = 0 To intByte - 1
                myFileStream.WriteByte(bteWrite(lngLoop))
            Next
            myFileStream.Close()
        Catch ex As IOException
            Console.WriteLine(ex.Message)
        End Try
    End Sub
End Class