FileInfo.OpenText Метод

Определение

Создает поток StreamReader с кодировкой UTF-8, который считывает данные из существующего текстового файла.Creates a StreamReader with UTF8 encoding that reads from an existing text file.

public:
 System::IO::StreamReader ^ OpenText();
public System.IO.StreamReader OpenText ();
member this.OpenText : unit -> System.IO.StreamReader
Public Function OpenText () As StreamReader

Возвращаемое значение

Новый объект StreamReader с кодировкой UTF8.A new StreamReader with UTF8 encoding.

Исключения

У вызывающего кода отсутствуют необходимые разрешения.The caller does not have the required permission.

Файл не найден.The file is not found.

path доступен только для чтения или является каталогом.path is read-only or is a directory.

Указан недопустимый путь (например, ведущий на несопоставленный диск).The specified path is invalid, such as being on an unmapped drive.

Примеры

Следующий пример считывает текст из файла.The following example reads text from a file.

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

public ref class OpenTextTest
{
public:
    static void Main()
    {
        String^ path = "c:\\MyTest.txt";

        FileInfo^ fi = gcnew FileInfo(path);

        // Check for existing file
        if (!fi->Exists)
        {
            // Create the file.
            FileStream^ fs = fi->Create();
            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);
            fs->Close();
        }

        // Open the stream and read it back.
        StreamReader^ sr = fi->OpenText();
        String^ s = "";
        while ((s = sr->ReadLine()) != nullptr)
        {
            Console::WriteLine(s);
        }
    }
};

int main()
{
    OpenTextTest::Main();
}
//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);

        // Check for existing file
        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);
                fs.Close();
            }
        }

        // Open the stream and read it back.
        using (StreamReader sr = fi.OpenText())
        {
            string s = "";
            while ((s = sr.ReadLine()) != null) 
            {
                Console.WriteLine(s);
            }
        }
    }
}
//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 OpenTextTest
    Public Shared Sub Main()
        Dim path As String = "c:\MyTest.txt"

        Dim fi As New FileInfo(path)

        ' Check for existing file
        If fi.Exists = false Then
            ' Create the file.
            Dim fs As FileStream = 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.
        Dim sr As StreamReader = fi.OpenText()
        Dim s As String = ""
        While sr.EndOfStream = false
            s = sr.ReadLine()
            Console.WriteLine(s)
        End While
        sr.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.
'

Безопасность

FileIOPermission
для чтения и записи файлов.for reading and writing files. Связанные перечисления: Read, WriteAssociated enumerations: Read, Write

Применяется к

Дополнительно