VB.Net by API/System.IO/FileStream

FileStream.Length

  
Imports System
Imports System.IO
Public Class MainClass
  Shared Sub Main()
    Dim i As Integer
    Dim theBytes(255) As Byte
    For i = 0 To 255
      theBytes(i) = CByte(i)
    Next
    Dim myFileStream As FileStream
    Try
      myFileStream = New FileStream("test.txt", FileMode.OpenOrCreate, FileAccess.Write)
      myFileStream.Write(theBytes, 0, 256)
    Finally
      If Not (myFileStream Is Nothing) Then myFileStream.Close()
    End Try

    Dim theFile As FileStream
    Try
      theFile = New FileStream("test.txt",FileMode.Open, FileAccess.Read)
      For i = 0 To (theFile.Length - 1)
        Console.Write(theFile.ReadByte)
      Next
    Catch e As Exception
      Throw e
    Finally
      If Not (theFile Is Nothing) Then theFile.Close()
    End Try
  End Sub
  
End Class

FileStream.Lock

  
Imports System.IO
Module Module1
    Sub Main()
        Dim FileSt As FileStream = New FileStream("test.dat", FileMode.Create, FileAccess.Write, FileShare.Write)
        Try
            FileSt.Lock(0, 100)
            Console.WriteLine("Locked")
        Catch Ex As Exception
            Console.WriteLine(Ex.Message)
        End Try
        Try
            FileSt.Unlock(0, 100)
            Console.WriteLine("Unlocked")
        Catch Ex As Exception
            Console.WriteLine(Ex.Message)
        End Try
        Dim Values As Byte()
        Values = New Byte() {1, 2, 3, 4, 5}
        Try
            FileSt.Seek(0, SeekOrigin.Begin)
            FileSt.Write(Values, 0, 5)
            Console.WriteLine("Successfully updated file")
        Catch Ex As Exception
            Console.WriteLine(Ex.Message)
        End Try
    End Sub
End Module

FileStream.Seek

  
Imports System.IO
Module Module1
    Sub Main()
        Dim FileSt As FileStream = New FileStream("test.dat", FileMode.Create, FileAccess.Write, FileShare.Write)
        Try
            FileSt.Lock(0, 100)
            Console.WriteLine("Locked")
        Catch Ex As Exception
            Console.WriteLine(Ex.Message)
        End Try
        Try
            FileSt.Unlock(0, 100)
            Console.WriteLine("Unlocked")
        Catch Ex As Exception
            Console.WriteLine(Ex.Message)
        End Try
        Dim Values As Byte()
        Values = New Byte() {1, 2, 3, 4, 5}
        Try
            FileSt.Seek(0, SeekOrigin.Begin)
            FileSt.Write(Values, 0, 5)
            Console.WriteLine("Successfully updated file")
        Catch Ex As Exception
            Console.WriteLine(Ex.Message)
        End Try
    End Sub
End Module

FileStream.SetLength

  
Imports System.IO
Imports System.Collections
Imports System.Windows.Forms
Imports System.Runtime.Serialization.Formatters.Binary
Imports System.Runtime.Serialization
Public Class MainClass
   Public Shared Sub Main()
      Const NUMBER_OF_RECORDS As Integer = 100
      Dim blankRecord As Employee = New Employee("f","l")
      Dim fileOutput As FileStream
      Dim binaryOutput As BinaryWriter
      Dim fileName As String = "test.dat"
      Dim i As Integer
         Try
            fileOutput = New FileStream(fileName,FileMode.Create, FileAccess.Write)
            fileOutput.SetLength(Employee.SIZE * NUMBER_OF_RECORDS)
            binaryOutput = New BinaryWriter(fileOutput)
            For i = 0 To NUMBER_OF_RECORDS - 1
               fileOutput.Position = i * Employee.SIZE
               binaryOutput.Write(blankRecord.firstName)
               binaryOutput.Write(blankRecord.lastName)
            Next
            Console.WriteLine("File Created")
         Catch fileException As IOException
            Console.WriteLine("Cannot write to file")
         End Try

      " close FileStream
      If (fileOutput Is Nothing) <> False Then
         fileOutput.Close()
      End If
      " close BinaryWriter
      If (binaryOutput Is Nothing) <> False Then
         binaryOutput.Close()
      End If
   End Sub
End Class
<Serializable()> Public Class Employee
   Public firstName, lastName As String
   Shared Public SIZE As Integer = 200 
   Public Sub New(ByVal first As String, ByVal last As String)
      firstName = first
      lastName = last
   End Sub 
   Public Overrides Function ToString() As String
      Return firstName & " " & lastName
   End Function 
End Class

FileStream.Unlock

  
Imports System.IO
Module Module1
    Sub Main()
        Dim FileSt As FileStream = New FileStream("test.dat", FileMode.Create, FileAccess.Write, FileShare.Write)
        Try
            FileSt.Lock(0, 100)
            Console.WriteLine("Locked")
        Catch Ex As Exception
            Console.WriteLine(Ex.Message)
        End Try
        Try
            FileSt.Unlock(0, 100)
            Console.WriteLine("Unlocked")
        Catch Ex As Exception
            Console.WriteLine(Ex.Message)
        End Try
        Dim Values As Byte()
        Values = New Byte() {1, 2, 3, 4, 5}
        Try
            FileSt.Seek(0, SeekOrigin.Begin)
            FileSt.Write(Values, 0, 5)
            Console.WriteLine("Successfully updated file")
        Catch Ex As Exception
            Console.WriteLine(Ex.Message)
        End Try
    End Sub
End Module

FileSystem.GetFileInfo

  
Public Class Tester
    Public Shared Sub Main
    
        Dim fileDetail As IO.FileInfo = My.ruputer.FileSystem.GetFileInfo("test.txt")
        Console.WriteLine(fileDetail.IsReadOnly)
        Console.WriteLine(CBool(fileDetail.Attributes And IO.FileAttributes.Hidden))
    End Sub
End Class

New FileStream(String fileName, FileMode fm)

  

Imports System.IO
Module Module1
    Sub Main()
        Dim Stream As FileStream
        Try
            Stream = New FileStream("test.dat", FileMode.Create)
        Catch E As Exception
            Console.WriteLine("Error creating test.Dat")
            Console.WriteLine("Error {0}", E.Message)
        End Try
        Dim BinaryStream As New BinaryWriter(Stream)
        Dim Age As Integer = 21
        Dim Salary As Double = 100000.0
        Dim Name As String = "Joe"
        Try
            BinaryStream.Write(Age)
            BinaryStream.Write(Salary)
            BinaryStream.Write(Name)
            BinaryStream.Close()
            Console.WriteLine("Data written to test.Dat")
        Catch E As Exception
            Console.WriteLine("Error writing to test.Dat")
            Console.WriteLine("Error {0}", E.Message)
        End Try
        
        "Read 
        
        Try
            Stream = New FileStream("test.dat", FileMode.Open)
        Catch E As Exception
            Console.WriteLine("Error opening test.Dat")
            Console.WriteLine("Error {0}", E.Message)
        End Try
        Dim BinaryStreamReader As New BinaryReader(Stream)
        Try
            Age = BinaryStreamReader.ReadInt32()
            Salary = BinaryStreamReader.ReadDouble()
            Name = BinaryStreamReader.ReadString()
            BinaryStreamReader.Close()
            Console.WriteLine("Age: {0}", Age)
            Console.WriteLine("Salary: {0}", Salary)
            Console.WriteLine("Name: {0}", Name)
        Catch E As Exception
            Console.WriteLine("Error reading to test.Dat")
            Console.WriteLine("Error {0}", E.Message)
        End Try
    End Sub
End Module