Compartir a través de


FileInfo.Open Método

Definición

Abre un archivo con varios privilegios de lectura y escritura y de uso compartido.

Sobrecargas

Open(FileMode)

Abre un archivo en el modo especificado.

Open(FileStreamOptions)

Inicializa una nueva instancia de la FileStream clase con el modo de creación especificado, el permiso de lectura y escritura y uso compartido, el acceso a otros FileStreams puede tener en el mismo archivo, el tamaño del búfer, las opciones de archivo adicionales y el tamaño de asignación.

Open(FileMode, FileAccess)

Abre un archivo en el modo especificado, con acceso de lectura o escritura (o ambos).

Open(FileMode, FileAccess, FileShare)

Abre un archivo en el modo especificado, con acceso de lectura o escritura (o ambos) y la opción de uso compartido especificada.

Open(FileMode)

Source:
FileInfo.cs
Source:
FileInfo.cs
Source:
FileInfo.cs

Abre un archivo en el modo especificado.

public:
 System::IO::FileStream ^ Open(System::IO::FileMode mode);
public System.IO.FileStream Open (System.IO.FileMode mode);
member this.Open : System.IO.FileMode -> System.IO.FileStream
Public Function Open (mode As FileMode) As FileStream

Parámetros

mode
FileMode

Constante FileMode que especifica el modo (por ejemplo, Open o Append) en que se abre el archivo.

Devoluciones

Archivo abierto en el modo especificado, con acceso de lectura y escritura y de uso no compartido.

Excepciones

No se encuentra el archivo.

El archivo es de solo lectura o es un directorio.

La ruta de acceso especificada no es válida, por ejemplo, está en una unidad no asignada.

El archivo ya está abierto.

Ejemplos

En el ejemplo siguiente se abre un archivo, se agrega información al archivo y se lee el archivo.

using namespace System;
using namespace System::IO;
using namespace System::Text;

int main()
{
   String^ path = "c:\\MyTest.txt";
   FileInfo^ fi = gcnew FileInfo( path );
   
   // Delete the file if it exists.
   if (  !fi->Exists )
   {
      //Create the file.
      FileStream^ fs = fi->Create();
      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 = fi->Open( FileMode::Open );
   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;
   }
}

//This code produces output similar to the following; 
//results may vary based on the computer/file structure/etc.:
//
//This is some text in the file.
//
//
//
//
//
//
//
//
//
//
//
//
//
using System;
using System.IO;
using System.Text;

class Test
{
    
    public static void Main()
    {
        string path = @"c:\MyTest.txt";
        FileInfo fi = new FileInfo(path);

        // Delete the file if it exists.
        if (!fi.Exists)
        {
            //Create the file.
            using (FileStream fs = fi.Create())
            {
                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 = fi.Open(FileMode.Open))
        {
            byte[] b = new byte[1024];
            UTF8Encoding temp = new UTF8Encoding(true);
            while (fs.Read(b,0,b.Length) > 0)
            {
                Console.WriteLine(temp.GetString(b));
            }
        }
    }
}
//This code produces output similar to the following;
//results may vary based on the computer/file structure/etc.:
//
//This is some text in the file.
//
//
//
//
//
//
//
//
//
//
//
//
Imports System.IO
Imports System.Text

Public Class Test

    Public Shared Sub Main()
        Dim path As String = "c:\temp\MyTest.txt"
        Dim fi As FileInfo = New FileInfo(path)
        Dim fs As FileStream

        ' Delete the file if it exists.
        If fi.Exists = False Then
            'Create the file.
            fs = fi.Create()
            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 = fi.Open(FileMode.Open)
        Dim b(1023) 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
'This code produces output similar to the following; 
'results may vary based on the computer/file structure/etc.:
'
'This is some text in the file.
'
'
'
'
'
'
'
'
'
'
'
'

Consulte también

Se aplica a

Open(FileStreamOptions)

Source:
FileInfo.cs
Source:
FileInfo.cs
Source:
FileInfo.cs

Inicializa una nueva instancia de la FileStream clase con el modo de creación especificado, el permiso de lectura y escritura y uso compartido, el acceso a otros FileStreams puede tener en el mismo archivo, el tamaño del búfer, las opciones de archivo adicionales y el tamaño de asignación.

public:
 System::IO::FileStream ^ Open(System::IO::FileStreamOptions ^ options);
public System.IO.FileStream Open (System.IO.FileStreamOptions options);
member this.Open : System.IO.FileStreamOptions -> System.IO.FileStream
Public Function Open (options As FileStreamOptions) As FileStream

Parámetros

options
FileStreamOptions

Objeto que describe los parámetros opcionales FileStream que se van a usar.

Devoluciones

que FileStream encapsula el archivo abierto.

Comentarios

FileStream(String, FileStreamOptions) para obtener información sobre las excepciones.

Se aplica a

Open(FileMode, FileAccess)

Source:
FileInfo.cs
Source:
FileInfo.cs
Source:
FileInfo.cs

Abre un archivo en el modo especificado, con acceso de lectura o escritura (o ambos).

public:
 System::IO::FileStream ^ Open(System::IO::FileMode mode, System::IO::FileAccess access);
public System.IO.FileStream Open (System.IO.FileMode mode, System.IO.FileAccess access);
member this.Open : System.IO.FileMode * System.IO.FileAccess -> System.IO.FileStream
Public Function Open (mode As FileMode, access As FileAccess) As FileStream

Parámetros

mode
FileMode

Constante FileMode que especifica el modo (por ejemplo, Open o Append) en que se abre el archivo.

access
FileAccess

Constante FileAccess que especifica si el archivo se abre con el acceso de archivo Read, Write o ReadWrite.

Devoluciones

Objeto FileStream abierto en el modo y con el acceso especificados y de uso no compartido.

Excepciones

El llamador no dispone del permiso requerido.

No se encuentra el archivo.

Name es de solo lectura o es un directorio.

La ruta de acceso especificada no es válida, por ejemplo, está en una unidad no asignada.

El archivo ya está abierto.

Name está vacía o solo contiene espacios en blanco.

Como mínimo un argumento es nulo.

Ejemplos

En el ejemplo siguiente se abre un archivo como de solo lectura y lectura del archivo.

using namespace System;
using namespace System::IO;
using namespace System::Text;

int main()
{
   String^ path = "c:\\MyTest.txt";
   FileInfo^ fi = gcnew FileInfo( path );
   
   // Delete the file if it exists.
   if (  !fi->Exists )
   {
      
      //Create the file.
      FileStream^ fs = fi->Create();
      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 = fi->Open( FileMode::Open, FileAccess::Read );
   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 ) );
      }
      try
      {
         //Try to write to the file.
         fs->Write( b, 0, b->Length );
      }
      catch ( Exception^ e ) 
      {
         Console::WriteLine( "Writing was disallowed, as expected: {0}", e );
      }
   }
   finally
   {
      if ( fs )
         delete (IDisposable^)fs;
   }
}
//This code produces output similar to the following; 
//results may vary based on the computer/file structure/etc.:
//
//This is some text in the file.
//
//
//
//
//
//
//
//
//
//
//
//
//Writing was disallowed, as expected: System.NotSupportedException: Stream does 
//not support writing.
//   at System.IO.__Error.WriteNotSupported()
//   at System.IO.FileStream.Write(Byte[] array, Int32 offset, Int32 count)
//   at main() in c:\documents and settings\MyComputer\my documents\
//visual studio 2005\projects\finfo open2\finfo open2\
//cpp_console_application.cpp:line 46
using System;
using System.IO;
using System.Text;

class Test
{
    
    public static void Main()
    {
        string path = @"c:\MyTest.txt";
        FileInfo fi = new FileInfo(path);

        // Delete the file if it exists.
        if (!fi.Exists)
        {
            //Create the file.
            using (FileStream fs = fi.Create())
            {
                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 = fi.Open(FileMode.Open, FileAccess.Read))
        {
            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 write to the file.
                fs.Write(b,0,b.Length);
            }
            catch (Exception e)
            {
                Console.WriteLine("Writing was disallowed, as expected: {0}",
                    e.ToString());
            }
        }
    }
}
//This code produces output similar to the following;
//results may vary based on the computer/file structure/etc.:
//
//This is some text in the file.
//
//
//
//
//
//
//
//
//
//
//
//
//Writing was disallowed, as expected: System.NotSupportedException: Stream does
//not support writing.
//   at System.IO.__Error.WriteNotSupported()
//   at System.IO.FileStream.Write(Byte[] array, Int32 offset, Int32 count)
//   at Test.Main() in C:\Documents and Settings\My Computer\My Documents\
//Visual Studio 2005\Projects\finfo open2\finfo open2\Program.cs:line 39
imports System.IO
imports System.Text

Public Class Test
    Public Shared Sub Main()
        Dim path As String = "c:\MyTest.txt"
        Dim fi As FileInfo = new FileInfo(path)
        Dim fs As FileStream

        ' Delete the file if it exists.
        If fi.Exists = False
            'Create the file.
            fs = fi.Create()
            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 = fi.Open(FileMode.Open, FileAccess.Read)
        Dim b(1023) 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
                fs.Write(b,0,b.Length)
                Catch e As Exception
                Console.WriteLine("Writing was disallowed, as expected: {0}", e.ToString())
            End Try
        fs.Close()
    End Sub
End Class
'This code produces output similar to the following; 
'results may vary based on the computer/file structure/etc.:
'
'This is some text in the file.
'
'
'
'
'
'
'
'
'
'
'
'
'Writing was disallowed, as expected: System.NotSupportedException: Stream does 
'not support writing.
'   at System.IO.__Error.WriteNotSupported()
'   at System.IO.FileStream.Write(Byte[] array, Int32 offset, Int32 count)
'   at VB_Console_Application.Test.Main() in C:\Documents and Settings\MyComputer
'\My Documents\Visual Studio 2005\Projects\finfo open2\finfo open2\Module1.vb:line 34
'

Consulte también

Se aplica a

Open(FileMode, FileAccess, FileShare)

Source:
FileInfo.cs
Source:
FileInfo.cs
Source:
FileInfo.cs

Abre un archivo en el modo especificado, con acceso de lectura o escritura (o ambos) y la opción de uso compartido especificada.

public:
 System::IO::FileStream ^ Open(System::IO::FileMode mode, System::IO::FileAccess access, System::IO::FileShare share);
public System.IO.FileStream Open (System.IO.FileMode mode, System.IO.FileAccess access, System.IO.FileShare share);
member this.Open : System.IO.FileMode * System.IO.FileAccess * System.IO.FileShare -> System.IO.FileStream
Public Function Open (mode As FileMode, access As FileAccess, share As FileShare) As FileStream

Parámetros

mode
FileMode

Constante FileMode que especifica el modo (por ejemplo, Open o Append) en que se abre el archivo.

access
FileAccess

Constante FileAccess que especifica si el archivo se abre con el acceso de archivo Read, Write o ReadWrite.

share
FileShare

Constante FileShare que especifica el tipo de acceso que otros objetos FileStream tienen en este archivo.

Devoluciones

Objeto FileStream abierto en el modo y con el acceso especificados y con opciones de uso compartido.

Excepciones

El llamador no dispone del permiso requerido.

No se encuentra el archivo.

Name es de solo lectura o es un directorio.

La ruta de acceso especificada no es válida, por ejemplo, está en una unidad no asignada.

El archivo ya está abierto.

Name está vacía o solo contiene espacios en blanco.

Como mínimo un argumento es nulo.

Ejemplos

En el ejemplo siguiente se muestra cómo abrir un archivo para leer y escribir, pero no permitir el acceso a otros usuarios o procesos.

using namespace System;
using namespace System::IO;
int main()
{
   
   // Open an existing file, or create a new one.
   FileInfo^ fi = gcnew FileInfo( "temp.txt" );
   
   // Open the file just specified such that no one else can use it.
   FileStream^ fs = fi->Open( FileMode::OpenOrCreate, FileAccess::ReadWrite, FileShare::None );
   
   // Create another reference to the same file.
   FileInfo^ nextfi = gcnew FileInfo( "temp.txt" );
   try
   {
      
      // Try opening the same file, which was locked by the previous process.
      nextfi->Open( FileMode::OpenOrCreate, FileAccess::Read );
      Console::WriteLine( "The file was not locked, and was opened by a second process." );
   }
   catch ( IOException^ ) 
   {
      Console::WriteLine( "The file could not be opened because it was locked by another process." );
   }
   catch ( Exception^ e ) 
   {
      Console::WriteLine( e );
   }

   
   // Close the file so it can be deleted.
   fs->Close();
}
//This code produces output similar to the following; 
//results may vary based on the computer/file structure/etc.:
//
//The file could not be opened because it was locked by another process.
using System;
using System.IO;

public class OpenTest
{
    public static void Main()
    {
        // Open an existing file, or create a new one.
        FileInfo fi = new FileInfo("temp.txt");

        // Open the file just specified such that no one else can use it.
        FileStream fs = fi.Open( FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.None );

        // Create another reference to the same file.
        FileInfo nextfi = new FileInfo("temp.txt");

        try
        {
            // Try opening the same file, which was locked by the previous process.
            nextfi.Open( FileMode.OpenOrCreate, FileAccess.Read );

            Console.WriteLine("The file was not locked, and was opened by a second process.");
        }
        catch (IOException)
        {
            Console.WriteLine("The file could not be opened because it was locked by another process.");
        }
        catch (Exception e)
        {
            Console.WriteLine(e.ToString());
        }

        // Close the file so it can be deleted.
        fs.Close();
    }
}

//This code produces output similar to the following;
//results may vary based on the computer/file structure/etc.:
//
//The file could not be opened because it was locked by another process.
Imports System.IO

Public Class OpenTest

    Public Shared Sub Main()
        ' Open an existing file, or create a new one.
        Dim fi As New FileInfo("temp.txt")

        ' Open the file just specified such that no one else can use it.
        Dim fs As FileStream = fi.Open(FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.None)

        ' Create another reference to the same file.
        Dim nextfi As New FileInfo("temp.txt")

        Try
            ' Try opening the same file, which was locked by the previous process.
            nextfi.Open(FileMode.OpenOrCreate, FileAccess.Read)
            Console.WriteLine("The file was not locked, and was opened by a second process.")
        Catch i as IOException
            Console.WriteLine(i.ToString())
        Catch e As Exception
            Console.WriteLine(e.ToString())
        End Try

        ' Close the file so it can be deleted.
        fs.Close()
    End Sub
End Class
'This code produces output similar to the following; 
'results may vary based on the computer/file structure/etc.:
'
'System.IO.IOException: The process cannot access the file 
''C:\Documents and Settings\mydirectory\My Documents\Visual Studio 2005
'\Projects\fileinfoopen\fileinfoopen\obj\Release\temp.txt' 
'because it is being used by another process.
'at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
'at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, 
'Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions
'options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy)
'at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access,
'FileShare share) at System.IO.FileInfo.Open(FileMode mode, FileAccess access)
'at VB_Console_Application.OpenTest.Main() in C:\Documents and Settings
'\mydirectory\My Documents\Visual Studio 2005\Projects\VB_Console_Application
'\VB_Console_Application\Module1.vb:line 19

Consulte también

Se aplica a