в 16:40, 26 мая 2010

2010-05-26T16:40:06Z

Admin: 1 версия

2010-05-26T12:45:20Z

1 версия

Новая страница

==Check Files Are Identical==

<source lang="vbnet">
Public Class MainClass
Public Shared Function CompareFiles(ByVal File1 As String, ByVal File2 As String) As Boolean
Dim blnIdentical As Boolean = True
Dim objFS1 As System.IO.FileStream = New System.IO.FileStream(File1, System.IO.FileMode.Open)
Dim objFS2 As System.IO.FileStream = New System.IO.FileStream(File2, System.IO.FileMode.Open)
If (objFS1.Length <> objFS2.Length) Then
blnIdentical = False
Else
Dim intByteF1 As Integer
Dim intByteF2 As Integer
Do
intByteF1 = objFS1.ReadByte()
intByteF2 = objFS2.ReadByte()
If intByteF1 <> intByteF2 Then
blnIdentical = False
Exit Do
End If
Loop While (intByteF1 <> -1)
End If
objFS1.Close()
objFS2.Close()
Return blnIdentical
End Function
Public Shared Sub Main()
If CompareFiles("1.jpg", "2.bmp") Then
System.Console.WriteLine("Files are identical!")
Else
System.Console.WriteLine("Files do not match!")
End If
End Sub
End Class

</source>

==Read and Write Binary file: int, string ==

<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>

==Read from a binary file==

<source lang="vbnet">
Imports System
Imports System.IO
Imports System.Windows.Forms
Public Class MainClass
Shared Sub Main()
Dim emp As New Employee
Dim file_num As Integer = FreeFile()
FileOpen(file_num, "MYFILE.DAT", OpenMode.Random, _
OpenAccess.ReadWrite, OpenShare.Shared, _
Len(emp))
FilePut(file_num, New Employee(1, "A", "A"))
FilePut(file_num, New Employee(2, "B", "B"))
FilePut(file_num, New Employee(3, "C", "C"))
FilePut(file_num, New Employee(4, "D", "D"))
FilePut(file_num, New Employee(5, "E", "E"))
FilePut(file_num, New Employee(6, "F", "F"))
Dim obj As ValueType = DirectCast(emp, ValueType)
For Each i As Integer In New Integer() {3, 1, 5, 2, 6}
FileGet(file_num, obj, i)
emp = DirectCast(obj, Employee)
Console.WriteLine(emp.ToString())
Next i
" Close the file.
FileClose(file_num)
End Sub
End Class
Public Structure Employee
Public ID As Integer
<VBFixedString(15)> Public FirstName As String
<VBFixedString(15)> Public LastName As String
Public Sub New(ByVal new_id As Integer, ByVal first_name As String, _
ByVal last_name As String)
ID = new_id
FirstName = first_name
LastName = last_name
End Sub
Public Overrides Function ToString() As String
Return ID & ": " & FirstName & " " & LastName
End Function
End Structure

</source>

==Reading a sequential-access file==

<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()
Dim formatter As BinaryFormatter = New BinaryFormatter()
Dim output As FileStream
Dim fileName As String = "test.dat"
Dim employee As Employee = New Employee("First Name", "Last Name")
Try
output = New FileStream(fileName,FileMode.OpenOrCreate, FileAccess.Write)

formatter.Serialize(output, employee)
output.Close()

Catch fileException As FileNotFoundException
Console.WriteLine("File Does Not Exits")
Catch serializableException As SerializationException
Console.WriteLine("Error Writing to File")
Catch formattingException As FormatException
Console.WriteLine("Invalid Format")
Catch e As IOException
Console.WriteLine("Cannot close file")
End Try

Dim input As FileStream
Dim reader As BinaryFormatter = New BinaryFormatter()
input = New FileStream(fileName, FileMode.Open,FileAccess.Read)
Try
Dim em As Employee = CType(reader.Deserialize(input), Employee)

Console.WriteLine(em)
Catch serializableException As SerializationException
input.Close()
Console.WriteLine("No more records in file")
End Try
End Sub
End Class
<Serializable()> Public Class Employee
Private firstName, lastName As String
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>

← Предыдущая	Версия 16:40, 26 мая 2010
(нет различий)

VB.Net/File Directory/Binary File Read - История изменений

в 16:40, 26 мая 2010

Admin: 1 версия