File.OpenText() Method in C# with Examples Last Updated : 28 Apr, 2025 Summarize Comments Improve Suggest changes Share Like Article Like Report File.OpenText(String) is an inbuilt File class method which is used to open an existing UTF-8 encoded text file for reading.Syntax: public static System.IO.StreamReader OpenText (string path); Parameter: This function accepts a parameter which is illustrated below: path: This is the specified text file which is going to be opened for reading. Exceptions: UnauthorizedAccessException: The caller does not have the required permission.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.FileNotFoundException: The file specified in the path was not found.NotSupportedException: The path is in an invalid format. Return Value: Returns a StreamReader on the specified path.Below are the programs to illustrate the File.OpenText(String) method.Program 1: Before running the below code, a text file file.txt is created with some contents shown below- Below code open the text file file.txt for reading. C# // C# program to illustrate the usage // of File.OpenText(String) method // Using System and System.IO // namespaces using System; using System.IO; class Test { public static void Main() { // Specifying a text file string path = @"file.txt"; // Opening the file for reading using(StreamReader sr = File.OpenText(path)) { string s = ""; while ((s = sr.ReadLine()) != null) { // printing the file contents Console.WriteLine(s); } } } } Executing: GeeksforGeeks Program 2: Initially, a file file.txt is created with some contents shown below- This below code will overwrite the file contents with other specified contents then final contents will be printed. C# // C# program to illustrate the usage // of File.OpenText(String) method // Using System and System.IO // namespaces using System; using System.IO; class Test { public static void Main() { // Specifying a text file string path = @"file.txt"; // Checking the existence of file if (File.Exists(path)) { using(StreamWriter sw = File.CreateText(path)) { // Overwriting the file with below // specified contents sw.WriteLine("GFG is a CS portal."); } } // Opening the file for reading using(StreamReader sr = File.OpenText(path)) { string s = ""; while ((s = sr.ReadLine()) != null) { // printing the overwritten content Console.WriteLine(s); } } } } Executing: GFG is a CS portal. 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