File.WriteAllLines(String, String[], Encoding) Method in C# with Examples

Last Updated : 25 Apr, 2025

File.WriteAllLines(String, String[], Encoding) is an inbuilt File class method that is used to create a new file, writes the specified string array to the file by using the specified encoding, and then closes the file.
Syntax:

public static void WriteAllLines (string path, string[] contents, System.Text.Encoding encoding);

Parameter: This function accepts three parameters which are illustrated below:

path: This is the specified file where specified string array are going to be written.
contents: This is the specified string array to write to the file.
encoding: This represents the character encoding applied to the string array.

Exceptions:

ArgumentException: The path is a zero-length string, contains only white space, or one or more invalid characters as defined by InvalidPathChars.
ArgumentNullException: Either path or contents are 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 the path specified a file that is hidden. 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.
NotSupportedException: The path is in an invalid format.
SecurityException: The caller does not have the required permission.

Below are the programs to illustrate the File.WriteAllLines(String, String[]) method.
Program 1: Initially, no file was created. Below code itself create a file file.txt and write the specified string array into the file.

C#

// C# program to illustrate the usage 
// of File.WriteAllLines(String, String[],  
// Encoding) 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"; 
  
        // Creating some string array to 
        // write into the file 
        string[] createText = { "GFG", "is a", "CS portal." }; 
  
        // Calling WriteAllLines() function to write 
        // the specified string array into the file 
        File.WriteAllLines(path, createText, Encoding.UTF8); 
  
        // Reading the file contents 
        string[] readText = File.ReadAllLines(path, Encoding.UTF8); 
        foreach(string s in readText) 
        { 
            Console.WriteLine(s); 
        } 
    } 
} 

Output:

GFG
is a
CS portal.

After running the above code, the above output is shown, and a new file file.txt is created shown below-

Program 2: Initially, a file file.txt is created with some contents shown below-

Below code overwrites the file contents with the specified string array.

C#

// C# program to illustrate the usage 
// of File.WriteAllLines(String,  
// String[], Encoding) 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"; 
  
        // Creating some string array to 
        // write into the file 
        string[] createText = { "GFG", "Geeks", "GeeksforGeeks" }; 
  
        // Calling WriteAllLines() function to overwrite 
        // the specified string array into the file 
        File.WriteAllLines(path, createText, Encoding.UTF8); 
  
        // Reading the file contents 
        string[] readText = File.ReadAllLines(path, Encoding.UTF8); 
        foreach(string s in readText) 
        { 
            Console.WriteLine(s); 
        } 
    } 
} 

Output:

GFG
Geeks
GeeksforGeeks

After running the above code, the above output is shown, and the file file.txt contents became like shown below-

File.WriteAllLines(String, String[]) Method in C# with Examples

Kanchan_Ray

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File.WriteAllLines(String, String[], Encoding) Method in C# with Examples

C#

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