How to: Read From a Text File (C# Programming Guide)

 

Updated: July 20, 2015

System_CAPS_ICON_note.jpg Note

For the latest documentation on C#, visit the C# Guide on docs.microsoft.com.

This example reads the contents of a text file by using the static methods ReadAllText and ReadAllLines from the System.IO.File class.

For an example that uses StreamReader, see How to: Read a Text File One Line at a Time.

System_CAPS_ICON_note.jpg Note

The files that are used in this example are created in the topic How to: Write to a Text File.

    class ReadFromFile
    {
        static void Main()
        {
            // The files used in this example are created in the topic
            // How to: Write to a Text File. You can change the path and
            // file name to substitute text files of your own.

            // Example #1
            // Read the file as one string.
            string text = System.IO.File.ReadAllText(@"C:\Users\Public\TestFolder\WriteText.txt");

            // Display the file contents to the console. Variable text is a string.
            System.Console.WriteLine("Contents of WriteText.txt = {0}", text);

            // Example #2
            // Read each line of the file into a string array. Each element
            // of the array is one line of the file.
            string[] lines = System.IO.File.ReadAllLines(@"C:\Users\Public\TestFolder\WriteLines2.txt");

            // Display the file contents by using a foreach loop.
            System.Console.WriteLine("Contents of WriteLines2.txt = ");
            foreach (string line in lines)
            {
                // Use a tab to indent each line of the file.
                Console.WriteLine("\t" + line);
            }

            // Keep the console window open in debug mode.
            Console.WriteLine("Press any key to exit.");
            System.Console.ReadKey();
        }
    }

Copy the code and paste it into a C# console application.

If you are not using the text files from How to: Write to a Text File, replace the argument to ReadAllText and ReadAllLines with the appropriate path and file name on your computer.

The following conditions may cause an exception:

  • The file doesn't exist or doesn't exist at the specified location. Check the path and the spelling of the file name.

Do not rely on the name of a file to determine the contents of the file. For example, the file myFile.cs might not be a C# source file.

System.IO
C# Programming Guide
File System and the Registry (C# Programming Guide)

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