VB.Net by API/System.IO/FileStream

FileStream.Length

<source lang="vbnet"> 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

 </source>

FileStream.Lock

<source lang="vbnet"> 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

 </source>

FileStream.Seek

<source lang="vbnet"> 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

 </source>

FileStream.SetLength

<source lang="vbnet"> 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

 </source>

FileStream.Unlock

<source lang="vbnet"> 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

 </source>

FileSystem.GetFileInfo

<source lang="vbnet"> 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

 </source>

New FileStream(String fileName, FileMode fm)

<source lang="vbnet">

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

 </source>