File.OpenRead(String) Method

public:
 static System::IO::FileStream ^ OpenRead(System::String ^ path);

public static System.IO.FileStream OpenRead(string path);

static member OpenRead : string -> System.IO.FileStream

Public Shared Function OpenRead (path As String) As FileStream

Parameters

Returns

A read-only FileStream on the specified path.

Exceptions

Examples

The following example opens a file for reading.

using System;
using System.IO;
using System.Text;

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

 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.OpenRead(path))
 {
 byte[] b = new byte[1024];
 UTF8Encoding temp = new UTF8Encoding(true);

 while (fs.Read(b,0,b.Length) > 0)
 {
 Console.WriteLine(temp.GetString(b));
 }
 }
 }
}

open System.IO
open System.Text

let path = @"c:\temp\MyTest.txt"

if File.Exists path |> not then
 // Create the file.
 use fs = File.Create path

 let info =
 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.
do
 use fs = File.OpenRead path
 let b = Array.zeroCreate 1024
 let temp = UTF8Encoding true

 while fs.Read(b, 0, b.Length) > 0 do
 printfn $"{temp.GetString b}"

Imports System.IO
Imports System.Text

Public Class Test
 Public Shared Sub Main()
 Dim path As String = "c:\temp\MyTest.txt"

 If Not File.Exists(path) Then
 ' Create the file.
 Using fs As FileStream = 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)
 End Using
 End If

 ' Open the stream and read it back.
 Using fs As FileStream = File.OpenRead(path)
 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
 End Using

 End Sub
End Class

Remarks

This method is equivalent to the FileStream(String, FileMode, FileAccess, FileShare) constructor overload with a FileMode value of Open, a FileAccess value of Read and a FileShare value of Read.

The path parameter is permitted to specify relative or absolute path information. Relative path information is interpreted as relative to the current working directory. To obtain the current working directory, see GetCurrentDirectory.

For a list of common I/O tasks, see Common I/O Tasks.

See also

• File and Stream I/O
• Reading Text From A File
• How to: Write Text to a File
• How to: Read and Write to a Newly Created Data File