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Working with Files
C
can read from and write to files using classes in the System.IO namespace.
The File class
The File class has methods for creating, reading, writing, and deleting files. To use it, add using System.IO; at the top of your file.
Write to a file
csharp
### File.WriteAllText("filename.txt", "Hello World!");
This creates filename.txt (or overwrites it) with the given text.
Read from a file
csharp
string content = File.ReadAllText("filename.txt");
Console.WriteLine(content); // Hello World!
Append to a file
csharp
### File.AppendAllText("filename.txt", " More text!");
Delete a file
csharp
if (File.Exists("filename.txt"))
{
### File.Delete("filename.txt");
}
Other common methods
| Method | What it does |
|---|---|
File.Exists(path) | true if the file exists |
File.Copy(src, dst) | copies a file |
File.Move(src, dst) | moves a file |
File.ReadAllLines(path) | reads all lines into a string array |
File.WriteAllLines(path, lines) | writes a string array as lines |
Catching errors
If a file doesn't exist and you try to read it, you'll get an exception. In a later module you'll learn to handle that with try...catch.
TL;DR
using System.IO;gives you file tools.File.WriteAllText/File.ReadAllTextare the basics.File.Exists,File.Delete,File.Copy,File.Movemanage files.- Missing files throw exceptions - handle them.