File.ReadAllText Method (String)


Opens a text file, reads all lines of the file, and then closes the file.

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

public static string ReadAllText(
	string path


Type: System.String

The file to open for reading.

Return Value

Type: System.String

A string containing all lines of the file.

Exception Condition

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


path is null.


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.


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


An I/O error occurred while opening the file.


path specified a file that is read-only.


This operation is not supported on the current platform.


path specified a directory.


The caller does not have the required permission.


The file specified in path was not found.


path is in an invalid format.


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.

Use the ReadAllText(String, Encoding) method overload when reading files that might contain imported text, because unrecognized characters may not be read correctly.

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

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.

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

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

        // This text is added only once to the file.
        if (!File.Exists(path))
            // Create a file to write to.
            string createText = "Hello and Welcome" + Environment.NewLine;
            File.WriteAllText(path, createText);

        // This text is always added, making the file longer over time
        // if it is not deleted.
        string appendText = "This is extra text" + Environment.NewLine;
        File.AppendAllText(path, appendText);

        // Open the file to read from.
        string readText = File.ReadAllText(path);


for access to read from a file or directory. Associated enumeration: FileIOPermissionAccess.Read

Universal Windows Platform
Available since 10
.NET Framework
Available since 2.0
Available since 4.0
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