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File.ReadAllText Method (String, Encoding)

Opens a file, reads all lines of the file with the specified encoding, and then closes the file.

Namespace:  System.IO
Assembly:  mscorlib (in mscorlib.dll)

'Declaration
Public Shared Function ReadAllText ( _
	path As String, _
	encoding As Encoding _
) As String

Parameters

path
Type: System.String

The file to open for reading.

encoding
Type: System.Text.Encoding

The encoding applied to the contents of the file.

Return Value

Type: System.String
A string containing all lines of the file.

ExceptionCondition
ArgumentException

path is a zero-length string, contains only white space, or contains one or more invalid characters as defined by InvalidPathChars.

ArgumentNullException

path is Nothing.

PathTooLongException

The specified path, file name, or both exceed the system-defined maximum length. For example, on Windows-based platforms, paths must be less than 248 characters, and file names must be less than 260 characters.

DirectoryNotFoundException

The specified path is invalid (for example, it is on an unmapped drive).

IOException

An I/O error occurred while opening the file.

UnauthorizedAccessException

path specified a file that is read-only.

-or-

This operation is not supported on the current platform.

-or-

path specified a directory.

-or-

The caller does not have the required permission.

FileNotFoundException

The file specified in path was not found.

NotSupportedException

path is in an invalid format.

SecurityException

The caller does not have the required permission.

This method opens a file, reads each line of the file, and then adds each line as an element of a string. It then closes the file. A line is defined as a sequence of characters followed by a carriage return ('\r'), a line feed ('\n'), or a carriage return immediately followed by a line feed. The resulting string does not contain the terminating carriage return and/or line feed.

This method attempts to automatically detect the encoding of a file based on the presence of byte order marks. Encoding formats UTF-8 and UTF-32 (both big-endian and little-endian) can be detected.

The file handle is guaranteed to be closed by this method, even if exceptions are raised.

To use the encoding settings as configured for your operating system, specify the Encoding.Default property for the encoding parameter.

The following code example demonstrates the use of the ReadAllText method to display the contents of a file. In this example a file is created, if it doesn't already exist, and text is added to it.

Imports System
Imports System.IO
Imports System.Text

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

        ' This text is added only once to the file. 
        If File.Exists(path) = False Then 

            ' Create a file to write to. 
            Dim createText As String = "Hello and Welcome" + Environment.NewLine
            File.WriteAllText(path, createText, Encoding.UTF8)
        End If 

        ' This text is always added, making the file longer over time 
        ' if it is not deleted. 
        Dim appendText As String = "This is extra text" + Environment.NewLine
        File.AppendAllText(path, appendText, Encoding.UTF8)

        ' Open the file to read from. 
        Dim readText As String = File.ReadAllText(path)
        Console.WriteLine(readText)
    End Sub 
End Class

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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