File.AppendText() Method in C# with Examples
File.AppendText() is an inbuilt File class method which is used to create a StreamWriter that appends UTF-8 encoded text to an existing file else it creates a new file if the specified file does not exist.
public static System.IO.StreamWriter AppendText (string path);
Parameter: This function accepts a parameter which is illustrated below:
- path: This is the file where UTF-8 encoded texts are going to be appended. The file is created if it doesn’t already exist.
- UnauthorizedAccessException: The caller does not have the required permission.
- ArgumentException: The path is a zero-length string, contains only white space, or contains one or more invalid characters as defined by InvalidPathChars.
- ArgumentNullException: The path is null.
- PathTooLongException: The given path, file name, or both exceed the system-defined maximum length.
- DirectoryNotFoundException: The given path is invalid i.e, the directory doesn’t exist or it is on an unmapped drive.
- NotSupportedException: The path is in an invalid format.
Return Value: Returns a stream writer that appends specified UTF-8 encoded texts to the specified file or to a new file.
Below are the programs to illustrate the File.AppendText() method.
Program 1: Before running the below code, a file file.txt is created with some contents which is shown below:
mcs -out:main.exe main.cs mono main.exe Geeks Gfg GFG GeeksforGeeks
After running the above code, above output is shown and the existing file file.txt becomes like below:
Program 2: Initially, no file is created and hence below code itself create a file named as file.txt
mcs -out:main.exe main.cs mono main.exe GeeksforGeeks is a computer science portal.
After running the above code, a new file file.txt is created which is shown below: