Podstawy programowania
(4)
dr Jerzy Bartoszek
jerzy.bartoszek@put.poznan.p
l
Obsługa plików
Przydatne składowe:
• przestrzeń nazw
System.IO
• Klasy:
– FileStream,
– StreamReader,
– StreamWriter
– BinaryReader,
– BinaryWriter,
Zapisywanie do pliku
tekstowego
Dim
fs
As New System.IO.
FileStream
( _
"
file.txt
", FileMode.
Create
, _
FileAccess.
Write
)
Dim w As New
StreamWriter
(
fs
)
w.BaseStream.
Seek
(0, SeekOrigin.End)
w.
WriteLine
("Here is the file's text.")
w.
Write
("Here is more file text." & _
ControlChars.CrLf)
w.WriteLine("And that's about it.")
w.
Flush
()
w.
Close
()
file.txt
fs
w
File
FileStrea
m
StreamWri
ter
Odczytywanie z pliku
tekstowego
Dim
fs
As New System.IO.
FileStream
( _
"
file.txt
", FileMode.
Open
, _
FileAccess.
Read
)
Dim r As New
StreamReader
(
fs
)
r.BaseStream.
Seek
(0, SeekOrigin.Begin)
While r.
Peek()
> -1
Text &= r.
ReadLine
() & _
ControlChars.CrLf
End While
r.
Close
()
file.txt
fs
r
File
FileStrea
m
StreamRead
er
Zapisywanie do pliku
binarnego
Dim
fs
As New System.IO.
FileStream
( _
"data.txt", FileMode.
Create
, _
FileAccess.
Write
)
Dim w As New
BinaryWriter
(
fs
)
w.BaseStream.
Seek
(0, SeekOrigin.End)
Dim LoopIndex As Int32
For LoopIndex = 0 To 19
w.
Write
(LoopIndex)
Next
w.
Flush
()
w.
Close
()
Odczytywanie z pliku
binarnego
Dim
fs
As New System.IO.
FileStream
( _
"data.dat", FileMode.
Open
, _
FileAccess.
Read
)
Dim r As New
BinaryReader
(
fs
)
r.BaseStream.
Seek
(0,
SeekOrigin.Begin)
For LoopIndex = 0 To 19
Text &= r.
ReadInt32
() & _
ControlChars.CrLf
r.
Close
()