FileInfo.OpenText Method

Reference

Definition

Namespace:: System.IO

Assemblies:: mscorlib.dll, System.IO.FileSystem.dll

Assemblies:: netstandard.dll, System.Runtime.dll

Assemblies:: netstandard.dll, System.IO.FileSystem.dll

Assemblies:: netstandard.dll, System.IO.FileSystem.dll, System.Runtime.dll

Assembly:: System.IO.FileSystem.dll

Assembly:: mscorlib.dll

Assembly:: netstandard.dll

Source:: FileInfo.cs

Source:: FileInfo.cs

Source:: FileInfo.cs

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

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

Returns

StreamReader

A new StreamReader with UTF8 encoding.

Exceptions

SecurityException

The caller does not have the required permission.

FileNotFoundException

The file is not found.

UnauthorizedAccessException

Name is read-only or is a directory.

DirectoryNotFoundException

The specified path is invalid, such as being on an unmapped drive.

Examples

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.
'

Applies to

Product	Versions
.NET	Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10
.NET Framework	1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard	1.3, 1.4, 1.6, 2.0, 2.1
UWP	10.0

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