Opens an existing file for reading.
(in mscorlib.dll)
Visual Basic (Declaration)
Public Shared Function OpenRead ( _
path As String _
) As FileStream
Dim path As String
Dim returnValue As FileStream
returnValue = File.OpenRead(path)
public static FileStream OpenRead(
string path
)
public:
static FileStream^ OpenRead(
String^ path
)
public static function OpenRead(
path : String
) : FileStream
This method is equivalent to the FileStream(String, FileMode, FileAccess, FileShare) constructor overload with a FileMode value of Open, a FileAccess value of Read and a FileShare value of Read.
The path parameter is permitted to specify relative or absolute path information. Relative path information is interpreted as relative to the current working directory. To obtain the current working directory, see GetCurrentDirectory.
For a list of common I/O tasks, see Common I/O Tasks.
The following example opens a file for reading.
Imports System
Imports System.IO
Imports System.Text
Public Class Test
Public Shared Sub Main()
Dim path As String = "c:\temp\MyTest.txt"
Dim fs As FileStream
' Delete the file if it exists.
If File.Exists(path) = False Then
' Create the file.
fs = File.Create(path)
Dim info As Byte() = New UTF8Encoding(True).GetBytes("This is some text in the file.")
' Add some information to the file.
fs.Write(info, 0, info.Length)
fs.Close()
End If
' Open the stream and read it back.
fs = File.OpenRead(path)
Dim b(1024) As Byte
Dim temp As UTF8Encoding = New UTF8Encoding(True)
Do While fs.Read(b, 0, b.Length) > 0
Console.WriteLine(temp.GetString(b))
Loop
fs.Close()
End Sub
End Class
using System;
using System.IO;
using System.Text;
class Test
{
public static void Main()
{
string path = @"c:\temp\MyTest.txt";
// Delete the file if it exists.
if (!File.Exists(path))
{
// Create the file.
using (FileStream fs = File.Create(path))
{
Byte[] info = new UTF8Encoding(true).GetBytes("This is some text in the file.");
// Add some information to the file.
fs.Write(info, 0, info.Length);
}
}
// Open the stream and read it back.
using (FileStream fs = File.OpenRead(path))
{
byte[] b = new byte[1024];
UTF8Encoding temp = new UTF8Encoding(true);
while (fs.Read(b,0,b.Length) > 0)
{
Console.WriteLine(temp.GetString(b));
}
}
}
}
using namespace System;
using namespace System::IO;
using namespace System::Text;
int main()
{
String^ path = "c:\\temp\\MyTest.txt";
// Delete the file if it exists.
if ( !File::Exists( path ) )
{
// Create the file.
FileStream^ fs = File::Create( path );
try
{
array<Byte>^info = (gcnew UTF8Encoding( true ))->GetBytes( "This is some text in the file." );
// Add some information to the file.
fs->Write( info, 0, info->Length );
}
finally
{
if ( fs )
delete (IDisposable^)fs;
}
}
// Open the stream and read it back.
FileStream^ fs = File::OpenRead( path );
try
{
array<Byte>^b = gcnew array<Byte>(1024);
UTF8Encoding^ temp = gcnew UTF8Encoding( true );
while ( fs->Read( b, 0, b->Length ) > 0 )
{
Console::WriteLine( temp->GetString( b ) );
}
}
finally
{
if ( fs )
delete (IDisposable^)fs;
}
}
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
.NET Framework
Supported in: 3.5, 3.0, 2.0, 1.1, 1.0
.NET Compact Framework
Supported in: 3.5, 2.0, 1.0
XNA Framework
Supported in: 3.0, 2.0, 1.0
Reference
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