File.Appendalllines(String, Ienumerable String, Encoding) Method In C#

In the vast domain of C# development, programmers often face scenarios where adept file manipulation is crucial. Whether it pertains to recording information, storing user settings, or handling application setups, the skill to write to a file seamlessly is essential. A technique that shines for its ease and efficiency is the File.AppendAllLines method.

Part of the System.IO namespace within C#, the File.AppendAllLines function provides a practical way to add lines to a file. Its key advantage is the capability to append new data to a file without replacing the existing content.

Syntax:

It has the following syntax:

Example


File.AppendAllLines(string path, IEnumerable<string> contents, Encoding encoding);

✅ path: It denotes the path to the file to which lines will be appended.
✅ contents: It represents an IEnumerable<string> encapsulating the lines to append.
✅ encoding: It specifies the character encoding applied to the contents.

Example:

Now, let's examine a real-world scenario demonstrating the application of File.AppendAllLines for appending lines to a file. Imagine a basic C# console program designed to record user interactions:

Example


using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
 
class Program
{
 static void Main()
 {
 // Log user activity
 LogUserActivity("John Doe logged in.");
 LogUserActivity("Jane Smith performed a data update.");
 LogUserActivity("Admin user accessed sensitive information.");
 
 // Display the contents of the log file
 DisplayLogFile("user_activity.log");
 }
 
 static void LogUserActivity(string activity)
 {
 // Define the path to the log file
 string logFilePath = "user_activity.log";
 
 // Create or append to the log file
 File.AppendAllLines(logFilePath, new List<string> { activity }, Encoding.UTF8);
 
 Console.WriteLine($"Logged: {activity}");
 }
 
 static void DisplayLogFile(string logFilePath)
 {
 // Read and display the contents of the log file
 try
 {
 string[] logContents = File.ReadAllLines(logFilePath);
 Console.WriteLine("\nLog File Contents:");
 
 foreach (string line in logContents)
 {
 Console.WriteLine(line);
 }
 }
 catch (FileNotFoundException)
 {
 Console.WriteLine($"File not found: {logFilePath}");
 }
 }
}

Output:

Output


Logged: John Doe logged in.
Logged: Jane Smith performed a data update.
Logged: Admin user accessed sensitive information.
 
Log File Contents:
John Doe logged in.
Jane Smith performed a data update.
Admin user accessed sensitive information.

Explanation:

Main Method:

✅ Commences the execution of the program.
✅ Records user activities through the LogUserActivity
✅ Exhibits the contents of the log file via the DisplayLogFile

LogUserActivity Method:

✅ Documents a user activity by adding a line to a designated log file.
✅ Specifies the log file path as "user_activity.log" .
✅ Utilizes AppendAllLines to append the given activity to the log file.
✅ It conveys a console message signifying the successful logging of the activity.

DisplayLogFile Method:

✅ It tries to retrieve and exhibit the contents of a log file.
✅ It utilizes ReadAllLines to fetch all lines from the indicated log file.
✅ It presents the log file contents on the console in an easily readable format.
✅ It captures a FileNotFoundException scenario and displays a pertinent error message.

It utilizes classes from the IO namespace to efficiently handle files, such as File, File.AppendAllLines, and File.ReadAllLines. To maintain accurate character encoding, it designates UTF8 when adding lines to the log file.

Recording Actions:

✅ The software logs three separate user actions: signing in, modifying data, and viewing confidential details.
✅ Every action is added to the "user_activity.log" file as a new entry.

Displaying Log File Contents:

Once the program finishes logging activities, it proceeds to read and display the information stored in the log file.

If the file is not found (FileNotFoundException), a suitable error message will be shown.

✅ It produces console feedback to indicate the recording of each operation.
✅ Afterward, it displays the log file's information on the console.

Conclusion:

In summary, the provided C# code demonstrates the effective use of the File.AppendAllLines function for efficient file handling. The primary program efficiently records user actions, methodically recording them in a designated file using clear and concise code. By utilizing the System.IO namespace, it emphasizes the smooth inclusion of file management functionalities, specifically highlighting the append action (File.AppendAllLines) and data retrieval (File.ReadAllLines). By incorporating Encoding.UTF8, it guarantees both compatibility and correct character encoding when adding lines to the log file.

In addition, the software's resilience is demonstrated by its careful management of exceptions, particularly in handling the possibility of a FileNotFoundException when trying to access the log file. The clarity of the code and its deliberate use of console messages enhance its educational worth, making it a valuable guide for developers looking for clear and efficient methods for working with files in C#. Essentially, this illustration acts as an educational tool, emphasizing optimal techniques in file manipulation and demonstrating the versatility and straightforwardness provided by the File.AppendAllLines function.

Syntax:

Example:

Conclusion:

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