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

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