FileInfo(String) Constructeur

Définition

Espace de noms:

System.IO

Assembly:

System.Runtime.dll

Source:

FileInfo.cs

Initialise une nouvelle instance de la classe FileInfo, qui sert de wrapper pour un chemin d'accès de fichier.

public:
 FileInfo(System::String ^ fileName);

public FileInfo (string fileName);

new System.IO.FileInfo : string -> System.IO.FileInfo

Public Sub New (fileName As String)

Paramètres

fileName

String

Nom qualifié complet du nouveau fichier, ou nom de fichier relatif. Ne placez pas de caractère de séparation de répertoire à la fin du chemin d’accès.

Exceptions

ArgumentNullException

fileName a la valeur null.

SecurityException

L'appelant n'a pas l'autorisation requise.

ArgumentException

.NET Framework et .NET Core versions antérieures à 2.1 : le nom de fichier est vide, contient uniquement des espaces blancs ou contient des caractères non valides.

UnauthorizedAccessException

L’accès à fileName a été refusé.

PathTooLongException

Le chemin et/ou le nom de fichier spécifiés dépassent la longueur maximale définie par le système.

NotSupportedException

fileName contient un signe deux-points (:) au milieu de la chaîne.

Exemples

L’exemple suivant utilise ce constructeur pour créer deux fichiers, qui sont ensuite écrits, lus à partir de, copiés et supprimés.

using namespace System;
using namespace System::IO;

int main()
{
   String^ path = "c:\\MyTest.txt";
   FileInfo^ fi1 = gcnew FileInfo( path );
   if (  !fi1->Exists )
   {
      //Create a file to write to.
      StreamWriter^ sw = fi1->CreateText();
      try
      {
         sw->WriteLine( "Hello" );
         sw->WriteLine( "And" );
         sw->WriteLine( "Welcome" );
      }
      finally
      {
         if ( sw )
            delete (IDisposable^)sw;
      }
   }

   //Open the file to read from.
   StreamReader^ sr = fi1->OpenText();
   try
   {
      String^ s = "";
      while ( s = sr->ReadLine() )
      {
         Console::WriteLine( s );
      }
   }
   finally
   {
      if ( sr )
         delete (IDisposable^)sr;
   }

   try
   {
      String^ path2 = String::Concat( path, "temp" );
      FileInfo^ fi2 = gcnew FileInfo( path2 );
      
      //Ensure that the target does not exist.
      fi2->Delete();
      
      //Copy the file.
      fi1->CopyTo( path2 );
      Console::WriteLine( "{0} was copied to {1}.", path, path2 );
      
      //Delete the newly created file.
      fi2->Delete();
      Console::WriteLine( "{0} was successfully deleted.", path2 );
   }
   catch ( Exception^ e ) 
   {
      Console::WriteLine( "The process failed: {0}", e );
   }
}

//This code produces output similar to the following; 
//results may vary based on the computer/file structure/etc.:
//
//Hello
//And
//Welcome
//c:\MyTest.txt was copied to c:\MyTest.txttemp.
//c:\MyTest.txttemp was successfully deleted.

using System;
using System.IO;

class Test
{
    
    public static void Main()
    {
        string path = @"c:\temp\MyTest.txt";
        FileInfo fi1 = new FileInfo(path);

        if (!fi1.Exists)
        {
            //Create a file to write to.
            using (StreamWriter sw = fi1.CreateText())
            {
                sw.WriteLine("Hello");
                sw.WriteLine("And");
                sw.WriteLine("Welcome");
            }	
        }

        //Open the file to read from.
        using (StreamReader sr = fi1.OpenText())
        {
            string s = "";
            while ((s = sr.ReadLine()) != null)
            {
                Console.WriteLine(s);
            }
        }

        try
        {
            string path2 = path + "temp";
            FileInfo fi2 = new FileInfo(path2);

            //Ensure that the target does not exist.
            fi2.Delete();

            //Copy the file.
            fi1.CopyTo(path2);
            Console.WriteLine("{0} was copied to {1}.", path, path2);

            //Delete the newly created file.
            fi2.Delete();
            Console.WriteLine("{0} was successfully deleted.", path2);
        }
        catch (Exception e)
        {
            Console.WriteLine("The process failed: {0}", e.ToString());
        }
    }
}
//This code produces output similar to the following;
//results may vary based on the computer/file structure/etc.:
//
//Hello
//And
//Welcome
//c:\MyTest.txt was copied to c:\MyTest.txttemp.
//c:\MyTest.txttemp was successfully deleted.

Imports System.IO

Class Test

    Public Shared Sub Main()
        Dim path As String = "c:\temp\MyTest.txt"
        Dim fi1 As FileInfo = New FileInfo(path)

        If fi1.Exists = False Then
            'Create a file to write to.
            Dim sw As StreamWriter = fi1.CreateText()
            sw.WriteLine("Hello")
            sw.WriteLine("And")
            sw.WriteLine("Welcome")
            sw.Flush()
            sw.Close()
        End If

        'Open the file to read from.
        Dim sr As StreamReader = fi1.OpenText()

        Do While sr.Peek() >= 0
            Console.WriteLine(sr.ReadLine())
        Loop

        Try
            Dim path2 As String = path + "temp"
            Dim fi2 As FileInfo = New FileInfo(path2)

            'Ensure that the target does not exist.
            fi2.Delete()

            'Copy the file.
            fi1.CopyTo(path2)
            Console.WriteLine("{0} was copied to {1}.", path, path2)

            'Delete the newly created file.
            fi2.Delete()
            Console.WriteLine("{0} was successfully deleted.", path2)

        Catch e As Exception
            Console.WriteLine("The process failed: {0}", e.ToString())
        End Try
    End Sub
End Class
'This code produces output similar to the following; 
'results may vary based on the computer/file structure/etc.:
'
'Hello
'And
'Welcome
'c:\MyTest.txt was copied to c:\MyTest.txttemp.
'c:\MyTest.txttemp was successfully deleted.

L’exemple suivant ouvre un fichier existant ou crée un fichier, ajoute du texte au fichier et affiche les résultats.

using namespace System;
using namespace System::IO;
int main()
{
   
   // Open an existing file, or create a new one.
   FileInfo^ fi = gcnew FileInfo( "temp.txt" );
   
   // Create a writer, ready to add entries to the file.
   StreamWriter^ sw = fi->AppendText();
   sw->WriteLine( "This is a new entry to add to the file" );
   sw->WriteLine( "This is yet another line to add..." );
   sw->Flush();
   sw->Close();
   
   // Get the information out of the file and display it.
   StreamReader^ sr = gcnew StreamReader( fi->OpenRead() );
   while ( sr->Peek() != -1 )
      Console::WriteLine( sr->ReadLine() );
}
//This code produces output similar to the following; 
//results may vary based on the computer/file structure/etc.:
//
//This is a new entry to add to the file
//This is yet another line to add...

using System;
using System.IO;

public class FileInfoMainTest
{
    public static void Main()
    {
        // Open an existing file, or create a new one.
        FileInfo fi = new FileInfo("temp.txt");
        // Create a writer, ready to add entries to the file.
        StreamWriter sw = fi.AppendText();
        sw.WriteLine("This is a new entry to add to the file");
        sw.WriteLine("This is yet another line to add...");
        sw.Flush();
        sw.Close();
        // Get the information out of the file and display it.
        StreamReader sr = new StreamReader( fi.OpenRead() );
        while (sr.Peek() != -1)
            Console.WriteLine( sr.ReadLine() );
    }
}
//This code produces output similar to the following;
//results may vary based on the computer/file structure/etc.:
//
//Add as many lines as you like...
//Add another line to the output...
//This is a new entry to add to the file
//This is yet another line to add...

Imports System.IO

Public Class FileInfoMainTest

    Public Shared Sub Main()
        ' Open an existing file, or create a new one.
        Dim fi As New FileInfo("temp.txt")
        ' Create a writer, ready to add entries to the file.
        Dim sw As StreamWriter = fi.AppendText()
        sw.WriteLine("This is a new entry to add to the file")
        sw.WriteLine("This is yet another line to add...")
        sw.Flush()
        sw.Close()
        Dim sr As New StreamReader(fi.OpenRead())
        ' Get the information out of the file and display it.
        While sr.Peek() <> -1
            Console.WriteLine(sr.ReadLine())
        End While
    End Sub
End Class
'This code produces output similar to the following; 
'results may vary based on the computer/file structure/etc.:
'
'This is a new entry to add to the file
'This is yet another line to add...

Remarques

Vous pouvez spécifier le nom complet ou le nom de fichier relatif, mais le case activée de sécurité obtient le nom complet.

Voir aussi

• Fichier et flux de données E/S
• Procédure : lire le texte d’un fichier
• Procédure : écrire du texte dans un fichier