Sets a date and time when the directory was last written to.
directoryInstance.LastWriteTime = newLastWriteTime
|string||newLastWriteTime||A date and time when the directory was last written to.|
directory dir = new directory("c:\somewhere...");
dir.LastWriteTime = "3/04/2016 4:13:00";
It's a wrapper of the System.IO.DirectoryInfo.LastWriteTime property.
The date and time string is converted to the C#'s DateTime type by the System.DateTime.Parse(String) method.
Links for reference