File.ReadAllText(String) Method in C# with Examples

Last Updated : 25 Apr, 2025

File.ReadAllText(String) is an inbuilt File class method that is used to open a text file then reads all the text in the file and then closes the file.
Syntax:

public static string ReadAllText (string path);

Parameter: This function accepts a parameter which is illustrated below:

path: This is the specified file to open for reading.

Exceptions:

ArgumentException: The path is a zero-length string, contains only white space, or one or more invalid characters as defined by InvalidPathChars.
ArgumentNullException: The path is null.
PathTooLongException: The specified path, file name, or both exceed the system-defined maximum length.
DirectoryNotFoundException: The specified path is invalid.
IOException: An I/O error occurred while opening the file.
UnauthorizedAccessException: The path specified a file that is read-only. OR this operation is not supported on the current platform. OR the path specified a directory. OR the caller does not have the required permission.
FileNotFoundException: The file specified in the path was not found.
NotSupportedException: The path is in an invalid format.
SecurityException: The caller does not have the required permission.

Return Value: Returns a string containing all the text in the file.
Below are the programs to illustrate the File.ReadAllText(String) method.
Program 1: Initially, a file file.txt is created with some contents shown below-

C#

// C# program to illustrate the usage 
// of File.ReadAllText(String) method 
  
// Using System, System.IO and 
// System.Text namespaces 
using System; 
using System.IO; 
using System.Text; 
  
class GFG { 
    public static void Main() 
    { 
        // Specifying a file 
        string path = @"file.txt"; 
  
        // Calling the ReadAllText() function 
        string readText = File.ReadAllText(path); 
  
        // Printing the file contents 
        Console.WriteLine(readText); 
    } 
} 

Output:

GFG
gfg
Geeks
GeeksforGeeks
geeksforgeeks

Program 2: Initially, no file was created. Below code itself create a file file.txt with some specified contents.

C#

// C# program to illustrate the usage 
// of File.ReadAllText(String) method 
  
// Using System, System.IO and 
// System.Text namespaces 
using System; 
using System.IO; 
using System.Text; 
  
class GFG { 
    public static void Main() 
    { 
        // Specifying a file 
        string path = @"file.txt"; 
  
        // Adding below contents to the file 
        string[] createText = { "GFG", "is", "a", "CS", "portal" }; 
        File.WriteAllLines(path, createText); 
  
        // Calling the ReadAllText() function 
        string readText = File.ReadAllText(path); 
  
        // Printing the file contents 
        Console.WriteLine(readText); 
    } 
} 

Output:

GFG
is
a
CS
portal

File.ReadAllText(String, Encoding) Method in C# with Examples

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File.ReadAllText(String) Method in C# with Examples

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