File.Replace

A file needs to be replaced. With File.Replace, we replace the contents of one file with another. The original file is then deleted.

We could implement this logic with a series of file calls. But the File.Replace method is simpler. We can perform the task with a single call.

Example

This program uses the File.WriteAllText method to create 2 local text files. Because no absolute directory is specified, they are created in the directory local to the executable.

using System.IO;

class Program
{
    static void Main()
    {
        // Write to local file 1.
        File.WriteAllText("test1.txt", "test1");

        // Write to local file 2.
        File.WriteAllText("test2.txt", "test2");

        // Replace contents of file 1 with contents of file 2.
        // ... Also create file 3 as backup.
        File.Replace("test2.txt", "test1.txt", "test3.txt");
    }
}
test1.txt: test2
test3.txt: test1

Output notes

The contents of test1.txt are now equal to the original contents of test2.txt. And test3.txt contains the contents of test1.txt.

The File.Replace method provides a much-needed mechanism to automatically replace the contents of a file. Not only this, but it allows you to back up the original data.