File.Open メソッド
指定したパスの FileStream を開きます。
オーバーロードの一覧
指定したパスの FileStream を読み取り/書き込みアクセスで開きます。
.NET Compact Framework でもサポート。
[Visual Basic] Overloads Public Shared Function Open(String, FileMode) As FileStream
[JScript] public static function Open(String, FileMode) : FileStream;
指定したモードとアクセスで、指定したパスの FileStream を開きます。
.NET Compact Framework でもサポート。
[Visual Basic] Overloads Public Shared Function Open(String, FileMode, FileAccess) As FileStream
[C#] public static FileStream Open(string, FileMode, FileAccess);
[C++] public: static FileStream* Open(String*, FileMode, FileAccess);
[JScript] public static function Open(String, FileMode, FileAccess) : FileStream;
読み取り、書き込み、または読み取り/書き込みアクセスを持つ指定モードと指定した共有オプションで、指定したパスの FileStream を開きます。
.NET Compact Framework でもサポート。
[Visual Basic] Overloads Public Shared Function Open(String, FileMode, FileAccess, FileShare) As FileStream
[C#] public static FileStream Open(string, FileMode, FileAccess, FileShare);
[C++] public: static FileStream* Open(String*, FileMode, FileAccess, FileShare);
[JScript] public static function Open(String, FileMode, FileAccess, FileShare) : FileStream;
使用例
[Visual Basic, C#, C++] ファイル共有を禁止して、ファイルを読み取り専用アクセスで開く例を次に示します。
[Visual Basic, C#, C++] メモ ここでは、Open のオーバーロード形式のうちの 1 つだけについて、使用例を示します。その他の例については、各オーバーロード形式のトピックを参照してください。
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.Open(path, FileMode.Open, FileAccess.Read)
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
Try
' Try to get another handle to the same file.
Dim fs2 As FileStream = File.Open(path, FileMode.Open)
' Do some task here.
fs2.Close()
Catch e As Exception
Console.Write("Opening the file twice is disallowed.")
Console.WriteLine(", as expected: {0}", e.ToString())
End Try
fs.Close()
End Sub
End Class
[C#]
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.Open(path, FileMode.Open, FileAccess.Read, FileShare.None))
{
byte[] b = new byte[1024];
UTF8Encoding temp = new UTF8Encoding(true);
while (fs.Read(b,0,b.Length) > 0)
{
Console.WriteLine(temp.GetString(b));
}
try
{
// Try to get another handle to the same file.
using (FileStream fs2 = File.Open(path, FileMode.Open))
{
// Do some task here.
}
}
catch (Exception e)
{
Console.Write("Opening the file twice is disallowed.");
Console.WriteLine(", as expected: {0}", e.ToString());
}
}
}
}
[C++]
#using <mscorlib.dll>
using namespace System;
using namespace System::IO;
using namespace System::Text;
int main() {
String* path = S"c:\\temp\\MyTest.txt";
// Delete the file if it exists.
if (!File::Exists(path)) {
// Create the file.
FileStream* fs = File::Create(path);
try {
Byte info[] = (new UTF8Encoding(true))->GetBytes(S"This is some text in the file.");
// Add some information to the file.
fs->Write(info, 0, info->Length);
} __finally {
if (fs) __try_cast<IDisposable*>(fs)->Dispose();
}
}
// Open the stream and read it back.
FileStream* fs = File::Open(path, FileMode::Open, FileAccess::Read, FileShare::None);
try {
Byte b[] = new Byte[1024];
UTF8Encoding* temp = new UTF8Encoding(true);
while (fs->Read(b,0,b->Length) > 0) {
Console::WriteLine(temp->GetString(b));
}
try {
// Try to get another handle to the same file.
FileStream* fs2 = File::Open(path, FileMode::Open);
try {
// Do some task here.
} __finally {
if (fs2) __try_cast<IDisposable*>(fs2)->Dispose();
}
} catch (Exception* e) {
Console::Write(S"Opening the file twice is disallowed.");
Console::WriteLine(S", as expected: {0}", e);
}
} __finally {
if (fs) __try_cast<IDisposable*>(fs)->Dispose();
}
}
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をクリックします。