What's required for Windows to update the "file modified" timestamp?

Question

Obviously it gets updated during a write operation, but are there any non-destructive operations that also force an update? Basically looking to be able to do the equivalent of the *nix touch command, but in C# programmatically.

Answer 1

Use the function SetFileTime (C++) or File.SetLastWriteTime (C#) to set the last write time to the current time.

Answer 2

System.IO.File.SetLastWriteTime(string path, DateTime lastWriteTime);

Answer 3

From .NET, use the LastWriteTime property of the FileSystemInfo object. There is, in fact, a complete Touch app in example of that property in the MSDN.