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

Last Updated : 01 Jun, 2020

File.WriteAllText(String, String) is an inbuilt File class method that is used to create a new file, writes the specified string to the file, and then closes the file. If the target file already exists, it is overwritten.

Syntax:

public static void WriteAllText (string path, string contents);

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

path: This is the specified file where specified string are going to be written.

contents: This is the specified string to write to the file.

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 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.WriteAllText(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# program to illustrate the usage 
// of File.WriteAllText(String, 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"; 
  
        // Creating a string 
        string createText = "GeeksforGeeks" + Environment.NewLine; 
  
        // Writing the string to the file 
        File.WriteAllText(path, createText); 
  
        // Reading the contents of the file 
        string readText = File.ReadAllText(path); 
        Console.WriteLine(readText); 
    } 
} 

Output:

GeeksforGeeks

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

file.txt

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

file.txt

Below code overwrites the file contents with the specified string.

// C# program to illustrate the usage 
// of File.WriteAllText(String, 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"; 
  
        // Creating a string 
        string createText = "GFG is a cs portal." + Environment.NewLine; 
  
        // Overwriting the string to the file 
        File.WriteAllText(path, createText); 
  
        // Reading the contents of the file 
        string readText = File.ReadAllText(path); 
        Console.WriteLine(readText); 
    } 
} 

Output:

GFG is a cs portal.

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

file.txt

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

Kanchan_Ray

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

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